2013-2015 Microchip Technology Inc. DS00001571B-page 1
General Description
The CAP1298 is a multiple channel capacitive touch
sensor controller. It contains eight (8) individual capac-
itive touch sensor inputs with programmable sensitivity
for use in touch sensor applications. Each sensor input
is calibrated to compensate for system parasitic cap ac-
itance and automatically recalibrated to compensate
for gradual environmental changes.
In addition, the CAP1298 can be configured to detect
proximity on one or more channels with an optional sig-
nal guard to reduce noise sensitivity and to isolate the
proximity antenna from nearby conductive surfaces
that would otherwise attenuate the e-field.
The CAP1298 includes Multiple Pattern Touch recogni-
tion that allows the user to select a specific set of but-
tons to be touched simultaneously. If this pattern is
detected, a status bit is set and an interrupt is gener-
ated.
The CAP1298 has Active and Standby states, each
with its own sensor input configuration controls. The
Combo state allows a combination of sensor input con-
trols to be used which enables one or more sensor
inputs to operate as buttons while another sensor input
is operating as a proximity detector. Power consump-
tion in the Standby and Combo states is dependent on
the number of sensor inputs enabled as well as averag-
ing, sampling time, and cycle time. Deep Sleep is the
lowest power state available, drawing 5µA (typical) of
current. In this state, no sensor inputs are active, and
communications will wake the device.
Applications
• Desktop and Notebook PCs
• LCD Monitors
• Consumer Electronics
• Appliances
Features
• Eight (8) Capacitive Touch Sensor Inputs
- Programmable sensitivity
- Automatic recal i bration
- Calibrates for parasitic capacitance
- Individual thresholds for each button
• Proximity Detection
• Signal Guard
- Isolates the proximity antenna from attenua-
tion
- Reduces system noise sensitivity effects on
inputs
• Multiple Button Pattern Detection
• Power Button Support
• Press and Hold Feature for Volume-like Applica-
tions
• 3.3V or 5V Supply
• Analog Filtering for System Noise Sources
• RF Detection and Avoidance Filters
• Digital EMI Blocker
• 8kV ESD Rating on All Pins (HBM)
• Low Power Operation
- 5µA quiescent current in Deep Sleep
- 50µA quiescent current in Standby (1 sensor
input monitore d)
- Samples one or more channels in Standby
• SMBus / I2C Compliant Communication Interface
• Available in a 16-pin 3mm x 3mm QFN RoHS
compliant package
• Available in a 14-pin SOIC RoHS compliant pack-
age
CAP1298
8-Channel Capacitive Touch Sensor Controller with
Proximity Detection & Signal Guard
CAP1298
DS00001571B-page 2 2013-2015 Microchip Technology Inc.
TO OUR VALUED CUSTOMERS
It is our intention to provide our valued customers with the best documentation possible to ensure successful use of your Microchip
products. To this end, we will continue to improve our publications to better suit your needs. Our publications will be refined and
enhanced as new volumes and updates are introduced.
If you have any questions or comments regarding this publication, please contact the Marketing Communication s Department via
E-mail at docerrors@microchip.com. We welcome your feedback.
Most Current Data Sheet
To obtain the most up-to-date version of this data sheet, please register at our Worldwide Web site at:
http://www.microchip.com
You can determine the version of a data sheet by examining its literature number found on the bottom outside corner of any page.
The last character of the literature number is the version number, (e.g., DS30000000A is version A of document DS30000000).
Errata
An errata sheet, describing minor operational differe nces from the data sheet an d recommende d workarounds, may exist for cur-
rent devices. As device/documentation issues become known to us, we will publish an errata sheet. The errata will specify the
revision of silicon and revision of document to which it applies.
To determine if an errata sheet exists for a particular device, please check with one of the following:
• Microchip’s Worldwide Web site; http://www.microchip.com
• Your local Microchip sales office (see last page)
When contacting a sales office, please specify which device, revision of silicon and data sheet (include -literature number) you are
using.
Customer Notific at ion Syst em
Register on our web site at www.microchip.com to receive the most current information on all of our products.
2013-2015 Microchip Technology Inc. DS00001571B-page 3
CAP1298
Table of Contents
1.0 Introduction ..................................................................................................................................................................................... 4
2.0 Pin Description and Configuration .................................................................................................................................................. 8
3.0 Functional Description .................................................................................................................................................................. 21
4.0 Register Descriptions .................................................................................................................................................................... 58
5.0 Operational Characteristics ............................................................................ ............................................................................... 69
6.0 Package Outline ............................................................................................................................................................................ 85
Appendix A: Data Sheet Revision History ........................................................................................................................................... 91
The Microchip Web Site ...................................................................................................................................................................... 93
Customer Change Notification Service ............................................................................................................................................... 93
Customer Support ............................................................................................................................................................................... 93
Product Identification System ............................................................................................................................................................. 94
CAP1298
DS00001571B-page 4 2013-2015 Microchip Technology Inc.
1.0 INTRODUCTION
1.1 Block Diagram
1.2 Pin Diagrams
FIGURE 1-1: CAP1298 BLOCK DIAGRAM
FIGURE 1-2: CAP1298 14-PIN SOIC
SMBus
Protocol
SMCLK
SMDATA
VDD GND
ALERT#
Capacitive Touch Sensing Algorithm
CS1 CS2 CS3 CS4 CS6 CS7 CS8
CS5 /
SG
CAP1298
1
2
3
4
14
13
12
11
5
6
7
10
9
8
CS2
CS1
ALERT#
SMDAT
SMCLK
N/C
CS3
CS4
CS5/SG
CS6
CS7
CS8
GNDVDD
2013-2015 Microchip Technology Inc. DS00001571B-page 5
CAP1298
1.3 Pin Description
FIGURE 1-3: CAP1298 PIN DIAGRAM (16-PIN QFN)
TABLE 1-1: PIN DESCRIPTION FOR CAP1298
QFN Pin
#SOIC Pin # Pin Name Pin Function Pin Type Unused
Connection
1 3 ALERT# ALERT# - Active low alert / interrupt out-
put for SMBus alert OD Connect to
Ground
24SMDATA
SMDATA - Bi-directional, open-drain
SMBus or I2C data - requires pull-up
resistor DIOD n/a
35SMCLK
SMCLK - SMBus or I2C clock input -
requires pull-up resistor DI n/a
4 7 VDD Positive Power supply Power n/a
56N/C
Not internally connected n/a Connect to
Ground
6-N/C
Not internally connected n/a Connect to
Ground
7 8 GND Ground Power n/a
8 - GND Ground Power n/a
99CS8
Capacitive Touch Sensor Input 8 AIO Connect to
Ground
10 10 CS7 Capacitive Touch Sensor Input 7 AIO Connect to
Ground
1
2
3
4
12
11
10
9
16
15
14
13
5
6
7
8
VDD
SMCLK
SMDATA
CS7
GND
CS5 / SG
CS6
CS1
CS2
CS4
CS8
CS3
GND
N/C
N/C
Exposed pad
ALERT#
CAP1298
DS00001571B-page 6 2013-2015 Microchip Technology Inc.
APPLICATION NOTE: All digital pins are 5V tolerant pins.
The pin types are described in Table 1-2, "Pin Types".
11 11 CS6 Capacitive Touch Sensor Input 6 AIO Connect to
Ground
12 12 CS5 / SG CS5 - Capacitive Touch Sensor Input 5 AIO Connect to
Ground
SG - Signal Guard Output AIO Leave Open
13 13 CS4 Capacitive Touch Sensor Input 4 AIO Connect to
Ground
14 14 CS3 Capacitive Touch Sensor Input 3 AIO Connect to
Ground
15 1 CS2 Capacitive Touch Sensor Input 2 AIO Connect to
Ground
16 2 CS1 Capacitive Touch Sensor Input 1 AIO Connect to
Ground
Bottom
pad -Exposed
pad Not internally connected, but recommend
grounding --
TABLE 1-2: PIN TYPES
Pin Type Description
Power This pin is used to supply power or ground to the device.
DI Digital Input - This pin is used as a digital input. This pin is 5V tolerant.
AIO Analog Input / Output - This pin is used as an I/O for analog signals.
DIOD Digital Input / Open Drain Output - This pin is used as a digital I/O. When it is used as an
output, it is open drain and requires a pull-up resistor. This pin is 5V tolerant.
OD Open Drain Digital Output - This pin is used as a digital output. It is open drain and requires
a pull-up resistor. This pin is 5V tolerant.
TABLE 1-1: PIN DESCRIPTION FOR CAP1298 (CONTINUED)
QFN Pin
#SOIC Pin # Pin Name Pin Function Pin Type Unused
Connection
2013-2015 Microchip Technology Inc. DS00001571B-page 7
CAP1298
2.0 ELECTRICAL SPECIFICATIONS
Note 2-1 Stresses above those listed could cause permanent damage to the device. This is a stress rating
only and functional operation of the device at any other condition above those indicated in the
operation sections of this specification is not implied.
Note 2-2 For the 5V tolera nt pins that have a pull- up resistor, the voltage difference between V5VT_PIN and VDD
must never exceed 3.6V.
Note 2-3 The Pa ckage Power Dissi pation specification assumes a recommended the rmal via design consis ting
of a 2x2 matrix of 0.3mm (12mil) vias at 1.0mm pitch connected to the ground plane with a 1.6 x
1.6mm thermal landing.
Note 2-4 Junction to Ambient (JA) is dependent on the design of the thermal vias. Without thermal vias and
a thermal landing, the JA will be higher.
TABLE 2-1: ABSOLUTE MAXIMUM RATINGS
Voltage on VDD pin -0.3 to 6.5 V
Voltage on CS pins to GND -0.3 to 4.0 V
Voltage on 5V tolerant pins (V5VT_PIN) -0.3 to 5.5 V
Voltage on 5V tolerant pins (|V5VT_PIN - VDD|) (see Note 2-2)0 to 3.6 V
Input current to any pin except VDD +10 mA
Output short circuit current Continuous N/A
Package Power Dissipation up to TA = 85°C for 16-pin QFN
(see Note 2-3)0.5 W
Junction to Ambient (JA) (see Note 2-4)70 °C/W
Operating Ambient Temperature Range -40 to 125 °C
Storage Temperature Range -55 to 150 °C
ESD Rating, All Pins, HBM 8000 V
CAP1298
DS00001571B-page 8 2013-2015 Microchip Technology Inc.
TABLE 2-1: ELECTRICAL SPECIFICATIONS
VDD = 3V to 5.5V, TA = 0°C to 85°C, all Typical values at TA = 25°C unless otherwise noted.
Characteristic Symbol Min Typ Max Unit Conditions
DC Power
Supply Voltage VDD 3.0 5.5 V
Supply Current ISTBY_DEF 120 170 µA Standby state active
1 sensor input monitored
Default conditions (8 avg, 70ms
cycle time)
ISTBY_LP 50 µA Standby state active
1 sensor input monitored
1 avg, 140ms cycle time
IDSLEEP_3V 5TBDµA Deep Sleep state active
No communications
TA < 40°C
3.135 < VDD < 3.465V
IDD 500 750 µA Capacitive Sensing Active
signal guard disabled
Capacitive Touch Sensor Inputs
Maximum Base
Capacitance CBASE 50 pF Pad untouched
Minimum Detectable
Capacitive Shift CTOUCH 20 fF Pad touched - default conditions
Recommended Cap
Shift CTOUCH 0.1 2 pF Pad touched - Not tested
Power Supply
Rejection PSR ±3 ±10 counts
/ V
Untouched Current Counts
Base Capacitance 5pF - 50pF
Negative Delta Counts disabled
Maximum sensitivity
All other parameters default
Power-On and Brown-out Reset (see Section 4.2, "Reset" )
Power-On Reset
Voltage VPOR 1 1.3 V Pin States Defined
Power-On Reset
Release Voltage VPORR 2.85 V Rising VDD
Ensured by design
Brown-Out Reset VBOR 2.8 V Falling VDD
VDD Rise Rate
(ensures internal
POR signal) SVDD 0.05 V/ms 0 to 3V in 60ms
Power-Up Timer
Period tPWRT 10 ms
Brown-Out Reset
Voltage Delay tBORDC 1µsV
DD = VBOR - 1
2013-2015 Microchip Technology Inc. DS00001571B-page 9
CAP1298
Timing
Time to
Communications
Ready tCOMM_DLY 15 ms
Time to First
Conversion Ready tCONV_DLY 170 200 ms
I/O Pins
Output Low Voltage VOL 0.4 V ISINK_IO = 8mA
Output High Voltage VOH VDD -
0.4 VI
SOURCE_IO = 8mA
Input High Voltage VIH 2.0 V
Input Low Voltage VIL 0.8 V
Leakage Current ILEAK ±5 µA powered or unpowered
TA < 85°C
pull-up voltage < 3.6V if
unpowered
SG Pin
Capacitive Drive
Capability CBASE_SG 20 200 pF capacitance to ground
SMBus Timing
Input Capacitance CIN 5pF
Clock Frequency fSMB 10 400 kHz
Spike Suppression tSP 50 ns
Bus Free Time Stop
to Start tBUF 1.3 µs
Start Setup Time tSU:STA 0.6 µs
Star t H old Time t HD:STA 0.6 µs
Stop Setup Time tSU:STO 0.6 µs
Data Hold Time tHD:DAT 0 µs When transmitting to the master
Data Hold Time tHD:DAT 0.3 µs When receiving from the master
Data Setup Time tSU:DAT 0.6 µs
Clock Low Period tLOW 1.3 µs
Clock High Period tHIGH 0.6 µs
Clock / Data Fall
Time tFALL 300 ns Min = 20+0.1CLOAD ns
TABLE 2-1: ELECTRICAL SPECIFICATIONS (CONTINUED)
VDD = 3V to 5.5V, TA = 0°C to 85°C, all Typical values at TA = 25°C unless otherwise noted.
Characteristic Symbol Min Typ Max Unit Conditions
CAP1298
DS00001571B-page 10 2013-2015 Microchip Technology Inc.
Clock / Data Rise
Time tRISE 300 ns Min = 20+0.1CLOAD ns
Capacitive Load CLOAD 400 pF per bus line
TABLE 2-1: ELECTRICAL SPECIFICATIONS (CONTINUED)
VDD = 3V to 5.5V, TA = 0°C to 85°C, all Typical values at TA = 25°C unless otherwise noted.
Characteristic Symbol Min Typ Max Unit Conditions
2013-2015 Microchip Technology Inc. DS00001571B-page 11
CAP1298
3.0 COMMUNICATIONS
3.1 Communications
The CAP1298 communicates using the SMBus or I2C prot oco l .
3.2 System Management Bus
The CAP1298 communicates w ith a host controller, such as an MCHP SIO, through the SMBus. The SMBus is a two-
wire serial communication protocol be tween a computer host and its peripheral devices. A detailed timing dia gram is
shown in Figure 3-1. Stretching of the SMCLK signal is supported; however , the CAP1298 will not stretch the clock sig-
nal.
3.2.1 SMBUS START BIT
The SMBus Start bit is defined as a tra nsition of the SMBus Data line from a logic ‘1’ state to a logic ‘0’ state while the
SMBus Clock line is in a logic ‘1’ state.
3.2.2 SMBUS ADDRESS AND RD / WR BIT
The SMBus Address Byte consists of the 7 -bit clien t addre ss fol lowed by the RD / WR indicator bi t. If this RD / WR bit
is a logic ‘0’, then the SMBus Host is writing data to the client device. If this RD / WR bit is a logic ‘1’, then the SMBus
Host is reading data from the client device.
3.2.3 The CAP1298responds to SMBus address 0101_000(r/w). SMBUS DATA BYTES
All SMBus Data bytes are sent most significant bit first and composed of 8-bits of information.
3.2.4 SMBUS ACK AND NACK BITS
The SMBus client will acknowledge all data bytes that it receives. This is done by the client device pulling th e SMBus
Data line low after the 8th bit of each byte that is transmitted. This applies to both the Write Byte and Block Write proto-
cols.
The Host will NACK (not acknowledge) the last data byte to be received from the client by holding the SMBus data line
high after the 8th data bit has been sent. For the Block Read protocol, the Host will ACK each data byte that it receives
except the last data byte.
3.2.5 SMBUS STOP BIT
The SMBus Stop bit is defined as a transition of the SMBus Data line from a l ogic ‘0’ state to a logic ‘1’ state while the
SMBus clock line is in a logic ‘1’ state. When the CAP1298 detects an SMBus Stop bit and it has be en communicating
with the SMBus protocol, it will reset its client interface and prepare to receive further communications.
FIGURE 3-1: SMBUS TIMING DIAGRAM
SMDATA
SMCLK
TBUF
PS S - Start Co ndition P - Stop Condition PS
THIGH
TLOW THD:STA TSU:STO
THD:STA THD:DAT TSU:DAT TSU:STA
TFALL
TRISE
CAP1298
DS00001571B-page 12 2013-2015 Microchip Technology Inc.
3.2.6 SMBUS TIMEOUT
The CAP1298 includes an SMBus timeout feature. Following a 30ms period of inactivity on the SMBus where the
SMCLK pin is held low, the device will timeout and reset the SMBus interface.
The timeout function defaults to disabled. It can b e enabled by setting the TIMEOUT bit in the Config uration register
(see Section 5.6, "Configuration Registers").
3.2.7 SMBUS AND I2C COMPATIBILITY
The major differences between SMBus and I2C devices are highlighted here. For more information, refer to the SMBus
2.0 specification.
1. CAP1298supports I2C fast mode at 400kHz. This covers the SMBus max time of 100kHz.
2. Minimum frequency for SMBus communications is 10kHz.
3. The SMBus client pro tocol wil l reset if the clock is held low longer than 30ms (timeout con dition). This can be
enabled in the CAP1298 by setting the TIMEOUT bit in the Configuration register. I2C does not have a timeout.
4. The SMBus client protocol will reset i f both the clock a nd the data line are hig h for longer than 200u s (idle con-
dition). This can be enabled in the CAP1298by setting the TIMEOUT bit in the C onfiguration register. I2C does
not have an idle condition.
5. I2C devices do not support the Alert Response Addre ss functio nality (which is optional for SMBus).
6. I2C devices support block read and write differently. I2C protocol allows for unlimited number of bytes to be sent
in either direction. The SMBus protocol requires that an additional data byte indicating number of bytes to read /
write is transmitted. The CAP1298 supports I2C formatting only.
3.3 SMBus Protocols
The CAP1298 is SMBus 2.0 compatible and supports Write Byte, Read Byte, Send Byte, and Receive Byte as valid
protocols as shown below.
All of the below protocols use the convention in Table 3-1.
3.3.1 SMBUS WR ITE BYTE
The Write Byte is used to write one byte of data to a specific register as shown in Table 3-2.
3.3.2 SMBUS READ BYTE
The Read Byte protocol is used to read one byte of data from the registers as shown in Table 3-3.
TABLE 3-1: PROTOCOL FORMAT
Data Sent to
Device Dat a Sent to the
HOst
Data sent Data sent
TABLE 3-2: WRITE BYTE PROTOCOL
Start Slave
Address WR ACK Register
Address ACK Register
Data ACK Stop
1 ->0 0101_000 0 0 XXh 0 XXh 0 0 -> 1
2013-2015 Microchip Technology Inc. DS00001571B-page 13
CAP1298
3.3.3 SMBUS SEND BYTE
The Send Byte protocol is used to set the intern al address register pointer to the correct address location. No d ata is
transferred durin g the Send Byte protocol as shown in Table 3-4.
APPLICATION NOTE: The Send Byte protocol is not functional in Deep Sleep (i.e., DSLEEP bit is set).
3.3.4 SMBUS RECEIVE BYTE
The Receive Byte protocol is used to read data from a register when the intern al register address pointer is known to
be at the right location (e.g. set via Send Byte). This is use d for consecutive reads of the same register as shown in
Table 3-5.
APPLICATION NOTE: The Receive Byte protocol is not functional in Deep Sleep (i.e., DSLEEP bit is set).
3.4 I2C Protocols
The CAP1298 supports I2C Block Read and Block Write.
The protocols listed below use the convention in Table 3-1.
3.4.1 BLOCK READ
The Block Read is used to read multiple data bytes from a group of contiguous registers as shown in Table 3-6.
APPLICATION NOTE: When using the Block Read protocol, the internal address pointer will be automatically
incremented after every data byte is received. It will wrap from FFh to 00h.
TABLE 3-3: READ BYTE PROTOCOL
Start Slave Address WR ACK Register
Address ACK Start Client Address RD ACK Register
Data NACK Stop
1->0 0101_000 0 0 XXh 0 1 ->0 0101_000 1 0 XXh 1 0 -> 1
TABLE 3-4: SEND BYTE PROTOCOL
Start Slave Address WR ACK Register Address ACK Stop
1 -> 0 0101_000 0 0 XXh 0 0 -> 1
TABLE 3-5: RECEIVE BYTE PROTOCOL
Start Slave Address RD ACK Register Data NACK Stop
1 -> 0 0101_000 1 0 XXh 1 0 -> 1
TABLE 3-6: BLOCK READ PROTOCOL
Start Slave
Address WR ACK Register
Address ACK Start Slave Address RD ACK Register Data
1->0 0101_000 0 0 XXh 0 1 ->0 0101_000 1 0 XXh
ACK REGISTER
DATA ACK REGISTER
DATA ACK REGISTER
DATA ACK . . . REGISTER
DATA NACK STOP
CAP1298
DS00001571B-page 14 2013-2015 Microchip Technology Inc.
3.4.2 BLOCK WRITE
The Block Write is used to write multiple data bytes to a group of contiguous registers as shown in Table 3-7.
APPLICATION NOTE: When using the Block Write protocol, the internal address pointer will be automatically
incremented after every data byte is received. It will wrap from FFh to 00h.
0 XXh 0 XXh 0 XXh 0 . . . XXh 1 0 -> 1
TABLE 3-7: BLOCK WRITE PROTOCOL
Start Slave
Address WR ACK Register
Address ACK Register
Data ACK
1 ->0 0101_000 0 0 XXh 0 XXh 0
Register
Data ACK Register
Data ACK . . . Register
Data ACK Stop
XXh 0 XXh 0 . . . XXh 0 0 -> 1
TABLE 3-6: BLOCK READ PROTOCOL
2013-2015 Microchip Technology Inc. DS00001571B-page 15
CAP1298
4.0 GENERAL DESCRIPTION
The CAP1298 is a multiple channel capacitive touch sensor. It contains eight (8) individual capacitive touch sensor
inputs with programmable sensitivity for use in touch sensor applications. Each sensor input is calibrated to compensate
for system parasitic capacitance and automatically recalibrated to compensate for gradual environmental changes.
In addition, the CAP1298 can be configured to detect proximity on one or mo re channels with an optiona l signal guard
to reduce noise sensitivity.
The CAP1298includes Multiple Pattern Touch recognition tha t allows the user to select a specific set of buttons to be
touched simultaneously. If this pattern is detected, a status bit is set and an interrupt is generated.
The CAP1298 has Active and Standby states, each with its own sensor input config uration controls. The Combo state
allows a combination of sensor input controls to be used which enables one or more sensor inputs to operate as buttons
while another sensor input is op erating as a proximity detector. Power consumption in the Standby and Comb o states
is dependent on the number of sensor inputs enabled as well as averaging, sampling time, and cycle time. Deep Sleep
is the lowest power state available, drawing 5µA (typical) of current. In this state, no sensor inputs are active, and com-
munications will wake the device.
The device communicates with a host controller using SMBus / I2C. The host controller may poll the device for updated
information at any time or it may configure the device to flag an interru pt whenever a touch is detected on any se nsor
pad.
A typical system diagram is shown in Figure 4-1.
FIGURE 4-1: SYSTEM DIAGRAM FOR CAP1298
CAP1298
CS7
SMDATA
SMCLK
Embedded
Controller
ALERT#
CS8
CS3
CS2
CS1
CS4 CS6 Touch
Button
Touch
Button
Touch
Button
Touch
Button
Touch
Button
Touch
Button
SG*
Proximity
Sensor
VDDGND
3.0V to 5.5V
* CS5 / SG is a multi-function pin. If not
using the signal guard shown here, CS5
can be another touch button.
10kOhm
resistors 3.0V to 5.5V
1.0uF0.1uF
CAP1298
DS00001571B-page 16 2013-2015 Microchip Technology Inc.
4.1 Power States
The CAP1298 has 4 power states depending on the status of the STBY, COMBO, and DSLEEP bits. When the device
transitions between power states, previously detected to uches (for channels that are being de-activated) ar e cleared
and the sensor input status bits are reset.
1. Active - The normal mode of operati on. The device is monito ring capacitive sensor inputs enabled in the Active
state.
2. S t andby - When the STBY bit is set, the device is monitoring the capacitive sensor inputs enabled in the S tandby
state. Interrupts can still be generated based on the enabled channels. The device will still respond to communi-
cations normally and can be returned to the Active state of operation by clearing the STBY bit. Power consump-
tion in this state is dependent on the number of sensor inputs enabled as well as averaging, sampling time, and
cycle time.
3. Combo - When the COMBO bit is set, the device is monitoring capacitive sensor inputs enabled in the Active
state as well as inputs enabled in the St andby state (hence the name “Combo”). Interrupts can still be generated
based on the enabled channels. The device wil l still respond to communications normally and can be returned
to the Active state of operation by clearing the COMBO bit. Power consumption in this state is dependent on the
number of sensor inputs enabled as well as averaging, sampling time, and cycle time .
4. Deep Sleep - When the DSLEEP bit is set, the device is in its lowest power state. It is not monitoring any capac-
itive sensor inputs. While in Deep Slee p, the CAP12 98 can be awa kened by SMBus communications targeting
the device. This will not cause the DSLEEP to be cleare d so the device will return to Deep Sleep once all com-
munications have stopped. The device can be returned to the Active state of operation by clearing the DSLEEP
bit.
4.2 Reset
The Power-On Reset (POR) circuit holds the device in reset until VDD has reached an acceptable level, Power-on Reset
Release V oltage (VPORR), for minimum operation. The power-up timer (PWRT) is used to extend the start-up period until
all device operation conditions have been met. The power-up timer starts after VDD reaches VPORR. POR and PORR
with slow rising VDD is shown in Figure 4-2.
The Brown-Out Reset (BOR) circuit ho lds the de vice in reset w hen VDD falls to a minimum level, VBOR for longer than
the BOR reset delay (tBORDC). After a BOR, when VDD rises above VPORR, the power-up timer is started again and must
finish before reset is released, as shown in Figure 4-2.
4.3 Capacitive Touch Sensing
The CAP1298 contains eight (8) independent capacitive touch sensor inputs. Each sensor input has dynamic range to
detect a change of capacitance due to a touch. Additionally, each sensor input can be con figured to be automati cally
and routinely recalibrated.
4.3.1 CAPACITIVE TOUCH SENSING SETTINGS
Controls for managing capacitive touch se nsor inputs are determined by the power state.
FIGURE 4-2: POR AND PORR WITH SLOW RISING VDD AND BOR WITH FALLING VDD
VDD
VBOR
TPWRT
GND
Undefined
SYSRST
VPOR
VPORR
TBORDC TPWRT
2013-2015 Microchip Technology Inc. DS00001571B-page 17
CAP1298
4.3.1.1 Active State Sensing Settin gs
The Active state is used for normal operation. Sensor inputs being monitored are determined by the Sensor Input Enable
Register(see Section 5.7, "Sensor Input Enable Register" ). Sensitivity is controlled by the Sen sitivity Control Register
(see Section 5.5, "Sensitivity Control Register"). Averaging, sample time, and cycle time are controlled by the Averaging
and Sampling Configuration Register (see Section 5.10, "Averaging and Sampling Configuration Register"). Each chan-
nel can have a separate touch detection threshold, as defined in the Sensor Input Threshold registers (see Section 5.19,
"Sensor Input Threshold Registers").
4.3.1.2 Standby State Sensing Settings
The S tandby state is used for standby operation. In general, fewer sensor inputs are enabled, and they are programmed
to have more sensitivity. Sensor inputs being monitored are determined by the St andby Channel Register (see Section
5.21, "Standby Channel Register"). Sensitivity is controlled by the Standby Sensitivity Register (see Section 5.23,
"Standby Sensitivity Register"). Averaging, sample time, and cycle time are controlled by the Averaging and Sampling
Configuration Register (see Section 5.22, "Standby Configuration Register"). There is one touch detection threshold,
which applies to all sensors enabled in Standby, as defined in the Standby Threshold Register (see Section 5.24,
"Standby Threshold Register").
4.3.1.3 Combo State Sensing Settings
The Combo state is used when a combination of proximity detection and normal button operation is required. When the
COMBO bit is set, the sensing cycle includes sensor inputs enabled in the Active state as well as sensor inputs enabled
in the S t andby st ate. Sensor inputs enabled in the Active state will use the Active settings described in Section 4. 3. 1.1 ,
"Active State Sensing Settings". Sensor inputs enabled in the Standby state will use the Standby settings described in
Section 4.3.1.2, "S tandby S tate Sensing Settings". If a sensor input is enabled in both the Active state and in the Standby
state, the Active state settings will be used in Combo state. The programmed cycle time is determined by STBY_CY_-
TIME[1:0].
The Combo state also has two gain settings. When the COMBO bit is set, the GAIN[1:0] control only applies to the sen-
sors enabled in the Active state, and the C_GAIN[1:0] control applies to the sensors enabled in the Standby state.
4.3.2 SENSING CYCLE
Except when in Deep Sleep, the device automatically initiates a sensing cycle and repeats the cycle every time it fin-
ishes. The cycle polls through each enabled sensor input starting with CS1 and extending through CS8. As each capac-
itive touch sensor input is polled, its measurement is compared against a baseline “not touched” measurement. If the
delta measurement is large enough to exceed the applicable threshold, a touch is detected and an interrupt can be gen-
erated (see Section 4.9.2, "Capacitive Sensor Input Interrupt Behavior").
The sensing cycle time is programmable (see Section 5.10, "Averaging and Sampling Configuration Register" and Sec-
tion 5.22, "S tandby Configuration Register"). If all enabled inputs can be sampled in less than the cycle time, the device
is placed into a l ower power state for th e remaind er of th e sensin g cycle. If the number of active sensor i nputs cannot
be sampled within the specified cycle time, the cycle time is extended and the device is not placed in a lower power
state.
4.4 Sensor Input Calibration
Calibration sets the Base Count Registers(Secti on 5.25, "Sensor Inpu t Base Count Registers") wh ich contain the “not
touched” values used for touch detection comparisons. Calibration automati cally occurs after a power-on reset (POR),
when sample time is ch anged, whe n th e gain is cha nge d, w hen the ca lib rati on sen siti vity i s change d, and whenever a
sensor input is newly enabled (for example , when transitioning from a powe r state in which it was disabled to a power
state in which it is enabled). During calibration, the analog sensing circuits are tuned to the capacitance of the untouched
pad. Then, samples are taken from each sensor input so th at a base count can be established. After calibration, the
untouched delta counts are zero.
APPLICATION NOTE: During the calibration routine, the sensor inputs will not detect a press for up to 200ms and
the Sensor Base Count Register values will be invalid. In addition, any press on the
corresponding sensor pads will invalidate the calibration.
The host controller can force a calibration for selected sensor inputs at any time using the Calibration Activate and S tatus
RegisterSection 5.10.1, "Calibration Activate and S tatus Register". When a bit is set, the corresponding capacitive touch
sensor input will be calibrated (both analog and digital). The bit is automatically cleared once the calibration routine has
successfully finished.
CAP1298
DS00001571B-page 18 2013-2015 Microchip Technology Inc.
If analog calibration fails for a se nsor input, the corresponding bit is not cleared in the Calibration Activate and Status
Register, and the ACAL_FAIL bit is set in the Genera l S t at us Register( Section 5.2, "Status Registers"). An interrupt can
be generated. Analog calib ration will fail if a noise bit is set or if the calibration value is at the ma ximum or minimum
value. If digital calibration fails to generate base counts for a sensor input in the operating range, which is +12.5% from
the ideal base count (see TABLE 4-1:), indicating the base capacitance is out of range, the corresponding BC_OUTx bit
is set in the Base Count Out of Limit R egister(Section 5.17, "Base Count Out of Limit Register"), and the BC_OUT bit
is set in the General Status Register (Section 5.2, "Status Registers"). An interrupt can be generated. By default, when
a base count is out of limit, analog calibration is repeated for the sensor input; alternatively, the sensor input can be
sampled using the out of limit base count(Section 5.6, "Configuration Registers"). Calibration sensitivity can be adjusted
for each sensor input based on capacitive touch pad capacitance.
During normal operation there are various opti ons for recalibrating the capacitive touch sensor inputs. Recalibration is
a digital adjustment of the base counts so that the untouched delta count is zero. After a recalibration, if a sensor input’s
base count ha s shi fted +12.5% from the ideal base count, a full calibration will be performed on the sensor input.
4.4.1 AUTOMATIC RECALIBRATION
Each sensor input is regularly recalibrated at a programmable rate(see CAL_CFG[2:0] in Section 5.18 , "Recalibrati on
Configuration Register" ). By default, the recali bration routine stores the average 64 previous measurements and peri-
odically updates the base “not touched” setting for the capacitive touch sensor input.
APPLICATION NOTE: Automatic recalibration only works when the delta count is below the active sensor input
threshold. It is disabled when a touch is detected.
4.4.2 NEGATIVE DELTA COUNT RECALIBRATION
It is possible that the device loses sensitivity to a touch. This may happen as a result of a noisy environment, reca libr a-
tion when the pad is touched but delta counts do not exceed the threshold, or other environmental changes. When this
occurs, the base untouched sensor input may generate negative delta count values. The NEG_DELTA_CNT[1:0]
bits(see Section 5.18, "Recalibration Configuration Register") can be set to force a recalibration after a specified number
of consecutive negative delta readings . After a de layed recalibration (see Section 4.4.3, "Delayed Recal ibration") the
negative delta count recalibration can correct after the touch is released.
APPLICATION NOTE: During this recalibration, the device will not respond to touches.
4.4.3 DELAYED RECALIBRATION
It is possible that a “stuck button” occurs when something is placed on a button which cau ses a touch to be detected
for a long period. By setting the MAX_ DUR_EN bit(see Section 5.6, "Configuration Re gisters"), a recalibration can be
forced when a touch is he ld on a button for longer than the duration specifie d in the MAX_DUR[3:0 ] bits (see Section
5.8, "Sensor Input Configuration Register").
Note 4-1 Delayed recalibration only works when the delta count is above the active sensor input threshold. If
enabled, it is invoked when a sensor pad touch is held longer than the MAX_DUR bit settings.
Note 4-2 For the power button, which requires that the button be held longer than a regular button, the time
specified by the MAX_DUR[3:0] bits is added to the time required to trigger th e qualifying event. This
will prevent the power button from being recalibrated during the time it is supposed to be held.
TABLE 4-1: IDEAL BASE COUNTS
Ideal Base Count Sample Time
3,200 320us
6,400 640us
12,800 1.28ms
25,600 2.56ms
2013-2015 Microchip Technology Inc. DS00001571B-page 19
CAP1298
4.5 Proximity Detection
Each sensor input can be configured to detect changes in capacitance due to proximity of a touch. This circuitry detects
the change of capacitance that is generated as an object approaches, but does not physically touch, the enabled sensor
pad(s). Generally, sensor inputs used to detect proximity have physically larger pads than standard buttons. In addition,
gain should be increased to increase sensitivity. To imp ro v e the signal, the signal guard feature may be used.
4.5.1 SIGNAL GUARD
The signal guard isolates the signal from virtual grounds, as shown in Figure 4-3. It can be used to isolate the proximity
antenna from nearby conductive surfaces that would otherwise attenuate the e-field.
4.6 Power Button
The CAP1298 has a “power button” feature. In general, buttons are set for q uick respo nse to a touch, especially when
buttons are used for number keypads. However, there are cases where a quick response is not desired, such as when
accidentally brushing the power button causes a device to turn off or on unexpectedly.
The power button feature allows a sensor input to be designated as the “power button” (see Section 5.26, "Power Button
Register"). The power button is configured so that a touch mu st be held on the button for a designated perio d of time
before an interrupt is generated; different times can be selected for the St andby and the Active states (see Section 5.27,
"Power Button Configuration Register"). The feature can also be enabled / disabled for both states separately.
APPLICATION NOTE: For the power button feature to work in the Standby and/or Active states, the sensor input
must be enabled in the applicable state. If the power button feature is enabled for both
Standby and Active and the COMBO bit is set, the Standby power button settings will be
used.
After the designated power button has been held for the designated time, an interrupt is generated and the PWR bit is
set in the General Status Register (see Section 5.2, "Status Registers").
4.7 Multiple Touch Pattern Detection
The multiple touch pattern (MTP) detection circuitry can be used to detect lid closure or othe r similar e vents. An event
can be flagged based on either a minimum number of sensor inputs or on specific sensor inputs simultaneously exceed-
ing an MTP threshold or having their Noise Flag Status Register bits set. An interrupt can also be generated. During an
MTP event, all touches are blocked (see Section 5.15, "Multiple Touch Pattern Configuration Register").
FIGURE 4-3: SIGNAL GUARD
CAP129X Device
CS pin
SIGNAL_GUARD
CS pin
Touch Pad
Touch Pad
CAP1298
DS00001571B-page 20 2013-2015 Microchip Technology Inc.
4.8 Noise Controls
4.8.1 LOW FREQUENCY NOISE DETECTION
Each sensor input has a low freque ncy noise detector that will sense if low frequency no ise is injected onto the input
with sufficient power to corrupt the readings. By default, i f this occurs, the device wil l reject the corrupted samplesee
DIS_ANA_NOISE bit in Section 5.6.1, "Configuration - 20h") and the correspon din g bit is set to a logic ‘1’ in the No ise
Flag Status register (see SHOW_RF_NOISE bit in Section 5.6.2, "Configuration 2 - 44h").
4.8.2 RF NOISE DETECTION
Each sensor input contains an integrated RF noise detector . This block will detect injected RF noise on the CS pin. The
detector threshold is dependent upon the noise frequency. By default, if RF noise is detected on a CS line, that sample
is removed and not compared against the threshold (see DIS_RF_NOISE bit in Section 5.6.2, "Configuration 2 - 44h").
4.8.3 NOISE STATUS AND CONFIGURATION
The Noise Flag Status (see Section 5.3, "Noise Flag Status Registers") bits can be used to indicate RF and/or other
noise. If the SHOW_RF_NOISE bit in the Configuration Register (see Section 5.6, "Configuration R egisters") is set to
0, the Noise Flag Status bit for the capacitive sensor input is set if any analog noise is detected. If the
SHOW_RF_NOISE bit is set to 1, the Noise Flag Status bits will only be set if RF noise is detected.
The CAP1208 offers optional noise filtering contro ls for both analog and digital noise.
For analog noise, there are options for whether the data should be considered invalid. By default, the DIS_ANA_NOISE
bit (see Section 5.6.1, "Configuration - 20h") will block a touch on a sensor input if low frequency analog noise is
detected; the sample is discarded. By defau lt, the DIS_RF_NOISE bit (see Section 5.6.2, "Configuration 2 - 44h") wi ll
block a touch on a sensor input if RF noise is detected; the sample is discarded.
For digital noise, sensor input noise thresholds can be set (see Section 5.20, "Sensor Input Noise Threshold Register").
If a capacitive touch sensor inpu t exceeds the Sensor Noise Threshold but does not exceed the touch threshold (Sensor
Threshold (see Section 5.19, "Sensor Input Threshold Registers") in the Active state or Sensor Standby Threshold in
the Standby state (Section 5.24, "Standby Threshold Register")), it is determined to be cause d by a noise spike. The
DIS_DIG_NOISE bit (see Section 5.6.1, "Configuration - 20h") can be set to discard samples that indicate a noise spike
so they are not used in the automatic recalibration routine (see Section 4.4.1, "Automatic Recalibration").
4.9 Interrupts
Interrupts are indicated by the setting of the INT bit in the Main Control Register(see Section 5.1, "Main Control Regis-
ter") and by assertion of the ALERT# pin. The ALERT# pin is cleared when the INT bit is cleared by the user . When the
INT bit is cleared by the user, status bits may be cleared (see Section 5.2, "Status Registers").
4.9.1 ALERT# PIN
The ALERT# pin is an active low output that is driven when an interrupt event is detected.
4.9.2 CAPACITIVE SENSOR INPUT INTERRUPT BEHAVIOR
Each sensor input can be programmed to enable / disable interrupts(see Section 5.11, "Interrupt Enable Register").
When enabled for a sensor input and the sensor input is not the designated power button, interrupts are generated in
one of two ways:
1. An interrupt is generated when a touch is detected and, as a user selectable option, when a release is detected
(by default - see INT_REL_n in Section 5.6.2, "Configuration 2 - 44h"). See FIGURE 4-5:.
2. If the repeat rate is ena bled then, so long as the tou ch is he ld, another in te rrupt will be g ene rate d ba sed on the
programmed repeat rate (see FIGURE 4-4:).
When the repeat rate is enabled for a sensor input (see Section 5.12, "Repeat Rate Enable Register"), the device uses
an additional control called MPRESS that determines whe ther a touch is flagged as a simple “touch” or a “press and
hold” (see Section 5.9, "Sensor Input Configuration 2 Register"). The MPRESS[3:0] bits set a minimum press timer.
When the button is touched, the timer begin s. If the sensor pad is released befo re the minimum press timer expires, it
is flagged as a touch and an interrupt (if enabled) is generated upon release. If the sensor input detects a touch for lon-
ger than this timer value, it is flagged as a “press and hold” event. So long as the touch is held, interrupts will be gener-
ated at the programmed repeat rate (see Section 5.8, "Sensor Input Configuration Register") and upon release (if
enabled).
2013-2015 Microchip Technology Inc. DS00001571B-page 21
CAP1298
If a sensor input is the designated power button, an interrupt is not generated as soon as a touch is detected and repeat
rate is not applicable. See Section 4.9.3, "Interrupts for the Power Button ".
APPLICATION NOTE: FIGURE 4-4: and FIGURE 4-5: show default operation which is to generate an interrupt upon
sensor pad release.
APPLICATION NOTE: The host may need to poll the device twice to determine that a release has been detected.
4.9.3 INTERRUPTS FOR THE POWER BUTTON
Interrupts are automatically enabled for the power button when the feature is enabled (see Section 4.6, "Power Button").
A touch must be held on the power button for the desig nated period of time before an interrupt is generated.
FIGURE 4-4: SENSOR INTERRUPT BEHAVIOR - REPEAT RATE ENABLED
FIGURE 4-5: SENSOR INTERRUPT BEHAVIOR - NO REPEAT RATE ENABLED
Touch Detected
INT bit
Button Status
Write to INT bit
Sensing Cycle
(35ms)
Min Press Setting
(280ms)
Interrupt on
Touch
Button Repeat Rate
(175ms) Button Repeat Rate
(175ms)
Interrupt on
Release
(optional)
ALERT# pin
CAP1298
DS00001571B-page 22 2013-2015 Microchip Technology Inc.
4.9.4 INTERRUPTS FOR MULTIPLE TOUCH PATTERN DETECTION
An interrupt can be generated when the MTP pattern is matched (see Section 5.15, "Multiple Touch Pattern Configura-
tion Register").
4.9.5 INTERRUPTS FOR SENSOR INPUT CALIBRATION FAILURES
An interrupt can be generated when the ACAL_FAIL bit is set, indicating the failure to complete analog calibration of
one or more sensor inputs(see Section 5.2, "Status Registers"). This interrupt can be enabl ed by setting the ACAL_-
FAIL_INT bit (see Section 5.6, "Configuration Registers").
An interrupt can be generated when the BC_OUT bit is set, indicating the base count is out of limit for one or more sen-
sor inputs(see Section 5.2, "S tatus Registers"). This interrupt can be enabled by setting the BC_OUT_INT bit (see Sec-
tion 5.6, "Configuration Registers" ).
4.9.6 INTERRUPTS FOR RESET
When the CAP1298 comes out of reset, an interrupt is generated, and the RESET bit is set.
2013-2015 Microchip Technology Inc. DS00001571B-page 23
CAP1298
5.0 REGISTER DESCRIPTION
The registers shown in Table 5-1 are accessible through the communications protocol. An entry of ‘-’ indicates that the
bit is not used and will always read ‘0’.
TABLE 5-1: REGISTER SET IN HEXADECIMAL ORDER
Register
Address R/W Register Name Function Default
Value Page
00h R/W Main Control Controls power states and indicates
an interrupt 00h Page 26
02h R/W General Status Stores general status bits 00h Page 28
03h R Sensor Input Status Returns the state of the sampled
capacitive touch sensor inputs 00h Page 28
0Ah R Noise Flag Status Stores the noise flags for sensor
inputs 00h Page 29
10h R Se nsor Input 1 Delta
Count Stores the delta count for CS1 00h Page 30
11h R Sensor Input 2 Delta
Count Stores the delta count for CS2 00h Page 30
12h R Se nsor Input 3 Delta
Count Stores the delta count for CS3 00h Page 30
13h R Se nsor Input 4 Delta
Count Stores the delta count for CS4 00h Page 30
14h R Se nsor Input 5 Delta
Count Stores the delta count for CS5 00h Page 30
15h R Se nsor Input 6 Delta
Count Stores the delta count for CS6 00h Page 30
16h R Se nsor Input 7 Delta
Count Stores the delta count for CS7 00h Page 30
17h R Se nsor Input 8 Delta
Count Stores the delta count for CS8 00h Page 30
1Fh R/W Sensitivity Control Controls the sensitivity of the
threshold and delta counts and data
scaling of the base counts 2Fh Page 30
20h R/W Configuration Controls general functionality 20h Page 32
21h R/W Sensor Input Enable Controls which sensor inputs are
monitored in Active FFh Page 33
22h R/W Sensor Input
Configuration Controls max duration and auto-
repeat delay A4h Page 34
23h R/W Sensor Input
Configuration 2 Controls the MPRESS (“press and
hold”) setting 07h Page 35
24h R/W Averaging and
Sampling Config Controls averaging and sampling
window for Active 39h Page 36
CAP1298
DS00001571B-page 24 2013-2015 Microchip Technology Inc.
26h R/W Calibration Activate
and Status Forces calibration for capacitive
touch sensor inputs and indicates
calibration failure 00h Page 38
27h R/W Interrupt Enable Determines which capacitive sensor
inputs can generate interrupts FFh Page 39
28h R/W Repeat Rate Enable Enables repeat rate for specific
sensor inputs FFh Page 39
29h R/W Signal Guard Enable Enables the signal guard for specific
sensor inputs 00h Page 40
2Ah R/W Multiple Touch
Configuration Determines the number of
simultaneous touches to flag a
multiple touch condition 80h Page 40
2Bh R/W Multiple Touch Pattern
Configuration Determines the multiple touch
pattern (MTP) configuration 00h Page 41
2Dh R/W Multiple Touch Pattern Determines the pattern or number of
sensor inputs used by the MTP
circuitry FFh Page 42
2Eh R Base Count Out of
Limit Indicates whether sensor inputs
have a base count out of limit 00h Page 43
2Fh R/W Recalibration
Configuration Determin es recalibration timi ng and
sampling window 8Ah Page 43
30h R/W Sensor Input 1
Threshold Stores the touch detection th reshold
for Active for CS1 40h Page 45
31h R/W Sensor Input 2
Threshold Stores the touch detection th reshold
for Active for CS2 40h Page 45
32h R/W Sensor Input 3
Threshold Stores the touch detection th reshold
for Active for CS3 40h Page 45
33h R/W Sensor Input 4
Threshold Stores the touch detection th reshold
for Active for CS4 40h Page 45
34h R/W Sensor Input 5
Threshold Stores the touch detection th reshold
for Active for CS5 40h Page 45
35h R/W Sensor Input 6
Threshold Stores the touch detection th reshold
for Active for CS6 40h Page 45
36h R/W Sensor Input 7
Threshold Stores the touch detection th reshold
for Active for CS7 40h Page 45
37h R/W Sensor Input 8
Threshold Stores the touch detection th reshold
for Active for CS8 40h
38h R/W Sensor Input Noise
Threshold Stores controls for selecting the
noise threshold for all sensor inputs 01h Page 45
Standby Configuration Registers
40h R/W Standby Channel Controls which sensor inputs are
enabled for Standby 00h Page 46
TABLE 5-1: REGISTER SET IN HEXADECIMAL ORDER (CONTINUED)
Register
Address R/W Register Name Function Default
Value Page
2013-2015 Microchip Technology Inc. DS00001571B-page 25
CAP1298
41h R/W Standby Configuration Controls averaging and sensing
cycle time for Standby 39h Page 46
42h R/W Standby Sensitivity Controls sensitivity settings used fo r
Standby 02h Page 48
43h R/W Standby Threshold Stores the touch dete ction threshold
for Standby 40h Page 49
44h R/W Configuration 2 Stores additional configuration
controls for the device 40h Page 32
Base Count Registers
50h R Sensor Input 1 Base
Count Stores the reference co unt value for
sensor input 1 C8h Page 49
51h R Sensor Input 2 Base
Count Stores the reference co unt value for
sensor input 2 C8h Page 49
52h R Sensor Input 3 Base
Count Stores the reference co unt value for
sensor input 3 C8h Page 49
53h R Sensor Input 4 Base
Count Stores the reference co unt value for
sensor input 4 C8h Page 49
54h R Sensor Input 5 Base
Count Stores the reference co unt value for
sensor input 5 C8h Page 49
55h R Sensor Input 6 Base
Count Stores the reference co unt value for
sensor input 6 C8h Page 49
56h R Sensor Input 7 Base
Count Stores the reference co unt value for
sensor input 7 C8h Page 49
57h R Sensor Input 8 Base
Count Stores the reference co unt value for
sensor input 8 C8h Page 49
Power Button Registers
60h R/W Power Button Specifies the power button 00h Page 50
61h R/W Power Button
Configuration Configures the power button feature 22h Page 50
Calibration Sensitivity Configuration Registers
80h R/W Calibration Sensitivity
Configuration 1 Stores calibration sensitivity settings
for proximity 00h Page 52
81h R/W Calibration Sensitivity
Configuration 2 Stores calibration sensitivity settings
for proximity 00h Page 52
Calibration Registers
B1h R Sensor Input 1
Calibration Stores the upper 8-bit calibration
value for CS1 00h Page 51
B2h R Sensor Input 2
Calibration Stores the upper 8-bit calibration
value for CS2 00h Page 51
TABLE 5-1: REGISTER SET IN HEXADECIMAL ORDER (CONTINUED)
Register
Address R/W Register Name Function Default
Value Page
CAP1298
DS00001571B-page 26 2013-2015 Microchip Technology Inc.
During power-on reset (POR), the default values are stored in the registers. A POR is initiated when power is first
applied to the part and the voltage on the VDD supply surpasses the POR level as specified in the electrical character-
istics.
When a bit is “set”, this means it’s at a logic ‘1’. When a bit is “cleared”, this means it’s at a logic ‘0’.
5.1 Main Control Register
The Main Contro l re gi ster controls the primary p ow e r state of the device (see Section 4.1, "Power States").
B3h R Sensor Input 3
Calibration Stores the upper 8-bit calibration
value for CS3 00h Page 51
B4h R Sensor Input 4
Calibration Stores the upper 8-bit calibration
value for CS4 00h Page 51
B5h R Sensor Input 5
Calibration Stores the upper 8-bit calibration
value for CS5 00h Page 51
B6h R Sensor Input 6
Calibration Stores the upper 8-bit calibration
value for CS6 00h Page 51
B7h R Sensor Input 7
Calibration Stores the upper 8-bit calibration
value for CS7 00h Page 51
B8h R Sensor Input 8
Calibration Stores the upper 8-bit calibration
value for CS8 00h Page 51
B9h R Sensor Input
Calibration LSB 1 Stores the 2 LSBs of the calib ration
value for CS1 - CS4 00h Page 51
BAh R Sensor Input
Calibration LSB 2 Stores the 2 LSBs of the calib ration
value for CS5 - CS8 00h Page 51
ID Registers
FDh R Product ID Stores a fixed value that identifies
the CAP1298 71h Page 52
FEh R Manufacturer ID Stores a fixed value that identifies
MCHP 5Dh Page 53
FFh R Revision Stores a fi xed value that represents
the revision number 00h Page 53
TABLE 5-2: MAIN CONTROL REGISTER
Addr R/W Register B7 B6 B5 B4 B3 B2 B1 B0 Default
00h R/W Main Control GAIN[1:0] STBY DSLEEP C_GAIN[1:0] COMBO INT 00h
TABLE 5-1: REGISTER SET IN HEXADECIMAL ORDER (CONTINUED)
Register
Address R/W Register Name Function Default
Value Page
2013-2015 Microchip Technology Inc. DS00001571B-page 27
CAP1298
If more than one power state bit is set, the actual power state will be as shown in Table 5-3, "Power S tate Bit Overrides".
Bits 7 - 6 - GAIN[1:0] - Controls the analog gain used by the capacitive touch sensing circuitry. As the gain is increased,
the effective sensitivity is likewise increased as a smaller delta capacitance is required to generate the same delta count
values. The sensiti vity se ttings may need to be adjusted alon g wi th th e gain settin gs such that data overflow doe s not
occur.
APPLICATION NOTE: The GAIN[1:0] settings apply to both Standby and Active states, unless the COMBO bit is
set. When the COMBO bit is set, this control only applies to the sensors enabled in the
Active state, and the C_GAIN[1:0] control applies to the sensors enabled in the Standby
state.
APPLICATION NOTE: Whenever the gain settings change, the device will recalibrate all sensor inputs as if they
had no base count.
Bit 5 - STBY - Enables Standby.
• ‘0’ (default) - The device is not in the Standby state.
• ‘1’ - The device is in the S tandby state. Cap acitive touch sensor input scanning is limited to the sensor inputs set in
the Standby Channel register (see Section 5.21, "Standby Channel Register"). The status registers will not be
cleared until read. Sensor inputs that are no longer sampled will flag a release and then remain in a non-touched
state.
Bit 4 - DSLEEP - Enables Deep Sleep.
• ‘0’ (default) - The device is not in the Deep Sleep state.
• ‘1’ - The device is in the Deep Sleep state. All sensor input scanning is disabled. The status registers are automat-
ically cleared and the INT bit is cleared..
Bits 3 - 2 - C_GAIN[1:0] - When the COMBO bit is set, this bit controls the analog gain used for capacitive touch sensor
inputs enabled in the Standby state. As the gain is increased, the effective sensitivity is likewise increased as a smaller
delta capacitance is required to generate the same delta count values. The Standby sensitivity settings may need to be
adjusted along with the gain settings such that data overflow does not occur.
TABLE 5-3: POWER STATE BIT OVERRIDES
DSLEEP COMBO STBY Power State
0 0 0 Active
0 0 1 Standby
0 1 X Combo
1 X X DSleep
TABLE 5-4: GAIN AND C_GAIN BIT DECODE
GAIN[1:0] or C_GAIN[1:0] Capacitive Touch Sensor Input Gain
10
00 1
01 2
10 4
11 8
CAP1298
DS00001571B-page 28 2013-2015 Microchip Technology Inc.
APPLICATION NOTE: The C_GAIN[1:0] setting is only used if the COMBO bit is set. When the COMBO bit is set,
this control only applies to the sensors enabled in the Standby state, and the GAIN[1:0]
control applies to the sensors enabled in the Active state.
Bit 1 - COMBO - Enables Combo state (see Sectio n 4.3.1.3, "Combo State Sensing Settings").
• ‘0’ (default) - The device is not in the Combo state.
• ‘1’ - The device is in the Combo state. The device is monitoring sensor inputs enabled in the Active state (see Sec-
tion 5.7, "Sensor Input Enable Register") as well as those enabled in the Standby state (see Secti o n 5. 21,
"Standby Channel Register"). The status registers will not be cleared until read. Sensor inputs that are no longer
sampled will flag a release and then remain in a non-touched state.
Bit 0 - INT - Indicates that there is an interrupt (see Section 4.9, "Interrupts"). When this bit is set, it asserts the ALER T#
pin. If a channel detects a touch but interrupts are not enabled for that channel (see Section 5.1 1, "Interrupt Enable Reg-
ister"), no action is taken. This bit i s cleared b y writing a logic ‘0 ’ to it. When this bit is cleared, the AL ERT# pin will be
deasserted, and all status registers will be cleared if the condition has been removed.
• ‘0’ - No interrupt pending.
• ‘1’ - An interrupt condition occurred, and the ALERT# pin has been asserted.
5.2 Sta tus Registers
All status bits are cleared when the device enters Deep Sleep (DSLEEP = ‘1’ - see Section 5.1, "Main Control Register").
5.2.1 GENERAL STATUS - 02H
Bit 6 - BC_OUT - Indicates that the base count is out of limit for one or more enabled sensor inputs (see Section 4 .4,
"Sensor Input Calibration"). This bit will not be cleared until all enabled sensor inputs have base counts within the limit.
• ‘0’ - All enabled sensor inputs have base counts in the operating range.
• ‘1’ - One or more enabled sensor inputs has the base count out of limit. A status bit is set in the Base Count Out of
Limit Register (see Section 5.17, "Base Count Out of Limit Register").
Bit 5 - ACAL_F AIL - Indicates analog calibration failure for one or more enabled sensor inputs (see Section 4.4, "Sensor
Input Calibration"). This bit will not be clea red until all enabled sens or inpu ts have successfully completed analog cali-
bration.
• ‘0’ - All enabled sensor inputs were successfully calibrated.
• ‘1’ - One or more enabled sensor inputs failed analog calibration. A status bit is set in the Calibration Active Regis-
ter (see Section 5.10.1, "Calibration Activate and S tatus Register").
Bit 4 - PWR - Indicates that the designated power button has been held for the designated time (see Section 4.6, "Power
Button"). This bit will cause the INT bit to be set. This bit is cleared when th e INT bit is cleared if there is no longer a
touch on the power button.
• ‘0’ - The power button has not be en held for the required time or is not enabled.
• ‘1’ - The power button has been held for the required time.
Bit 3 - RESET - Indicates that the device has come out of reset. This bit is set when the device exits a POR state. This
bit will cause the INT bit to be set and is cleared when the INT bit is cleared.
Bit 2 - MULT - Indicates that the device is b locking detected touche s due to the Multi ple Touch detection circuitry (see
Section 5.14, "Multiple Touch Configuration Register"). T his bit will not cause the INT bit to be set and hence will not
cause an interrupt.
TABLE 5-5: STATUS REGISTERS
Addr R/W Register B7 B6 B5 B4 B3 B2 B1 B0 Default
02h R General Status - BC_
OUT ACAL
_FAIL PWR RESET MULT MTP TOUCH 00h
03h R Sensor Input
Status CS8 CS7 CS6 CS5 CS4 CS3 CS2 CS1 00h
2013-2015 Microchip Technology Inc. DS00001571B-page 29
CAP1298
Bit 1 - MTP - Indicates that the device has detected a number of sensor inputs that exceed the MTP threshold either via
the pattern recognition or via the number of sensor inputs (see Section 5.15, "Multiple Touch Pattern Configuration Reg-
ister"). This bit will cause the INT bit to be set if the MTP_ALERT bit is also set. This bi t is cleared when the IN T bit is
cleared if the condition that caused it to be se t has been removed.
Bit 0 - TOUC H - Indi ca te s that a to u ch w as de tected. This bit is set if any bit in the Sensor Input Status register is set.
5.2.2 SENSOR INPUT STATUS - 03H
The Sensor Input Status Register stores status bits that indicate a touch has been detected. A value of ‘0’ in any bit
indicates th at no to u ch ha s be en detected. A value of ‘1’ in any bit indicates that a touch has been detected.
All bits are cleared when the INT bit is cleared and if a touch on the respective capacitive touch sensor input is no longer
present. If a touch is still detected, the bits will not be cleared (but this will not cause the interru pt to be asserted).
Bit 7 - CS8 - Indicates that a touch was detected on Sensor Input 8.
Bit 6 - CS7 - Indicates that a touch was detected on Sensor Input 7.
Bit 5 - CS6 - Indicates that a touch was detected on Sensor Input 6.
Bit 4 - CS5 - Indicates that a touch was detected on Sensor Input 5.
Bit 3 - CS4 - Indicates that a touch was detected on Sensor Input 4.
Bit 2 - CS3 - Indicates that a touch was detected on Sensor Input 3.
Bit 1 - CS2 - Indicates that a touch was detected on Sensor Input 2.
Bit 0 - CS1 - Indicates that a touch was detected on Sensor Input 1.
5.3 Noise Flag Status Registers
The Noise Flag St atus registers store status bits that can be used to indicate that the analog block detected noise above
the operating region of the analog detector or the RF noise detector (see Section 4 .8.3, "Noise Status and Configura-
tion"). These bits indicate that the most recentl y received data from the sensor input is invalid and shou ld not be used
for touch detection. So long a s the bit is set for a particular channel, the delta count value is reset to 00 h and thus no
touch is detected.
These bits are not sticky and will be cleared automatically if the analog block does not report a noise error.
APPLICATION NOTE: If the MTP detection circuitry is enabled, these bits count as sensor inputs above the MTP
threshold (see Section 4.7, "Multiple Touch Pattern Detection") even if the corresponding
delta count is not. If the corresponding delta count also exceeds the MT P threshold , it is not
counted twice.
APPLICATION NOTE: Regardless of the state of the Noise Status bits, if low frequency noise is detected on a
sensor input, that sample will be discarded unless the DIS_ANA_NOISE bit is set. As well,
if RF noise is detected on a sensor input, that sample will be discarded unless the
DIS_RF_NOISE bit is set.
TABLE 5-6: NOISE FLAG S TATUS REGISTERS
AddrR/W Register B7 B6B5B4B3B2B1B0Default
0Ah R Noise Flag
Status CS8_
NOISE CS7_
NOISE CS6_
NOISE CS5_
NOISE CS4_
NOISE CS3_
NOISE CS2_
NOISE CS1_
NOISE 00h
CAP1298
DS00001571B-page 30 2013-2015 Microchip Technology Inc.
5.4 Sensor Input Delta Count Registers
The Sensor Input Delta Count registers store the delta count that is compared against the threshold used to determine
if a touch has been dete cted. The count value represents a change in input due to the capacitance associated with a
touch on one of the sensor inputs and is referenced to a calibrated base “not touched” count value. The delta is an
instantaneous change and is updated once per sensor input per sensing cycle (see Section 4.3.2, "Sensing Cycle").
The value presented is a standard 2’s complement number . In addition, the value is capped at a value of 7Fh. A reading
of 7Fh indicates that the sensitivity settings are too high and should be adjusted accordingly (see Section 5.5).
The value is also capped at a neg ative value of 80h for negative delta counts which may result upon a release.
5.5 Sensitivity Control Register
The Sensitivity Control register controls the sensitivity of a touch detection.
Bits 6-4 DELTA_SENSE[2:0] - Controls the sensitivity of a touch detection for sensor inputs enabled in the Active state.
The sensitivity settings act to scale the relative delta count value higher or lower based on the system parameters. A
setting of 000b is the most sensitive while a setting of 1 11b is the least sensitive. At the more sensitive settings, touches
are detected for a smaller delta capacitance corresponding to a “lighter” touch. These settings are more sensitive to
noise, however, and a noisy environment may flag more false touches with higher sensitivity levels.
APPLICATION NOTE: A value of 128x is the most sensitive setting available. At the most sensitive settings, the
MSB of the Delta Count register re presents 64 out of ~25,000 which co rresponds to a touch
of approximately 0.25% of the base capacitance (or a C of 25fF from a 10pF base
capacitance). Conversely, a value of 1x is the least sensitive setting available. At these
TABLE 5-7: SENSOR INPUT DELTA COUNT REGISTERS
AddrR/W Register B7B6B5B4B3B2B1B0Default
10h R Sensor Input 1
Delta Count Sign 64 32 16 8 4 2 1 00h
11h R Sensor Input 2
Delta Count Sign 64 32 16 8 4 2 1 00h
12h R Sensor Input 3
Delta Count Sign 64 32 16 8 4 2 1 00h
13h R Sensor Input 4
Delta Count Sign 64 32 16 8 4 2 1 00h
14h R Sensor Input 5
Delta Count Sign 64 32 16 8 4 2 1 00h
15h R Sensor Input 6
Delta Count Sign 64 32 16 8 4 2 1 00h
16h R Sensor Input 7
Delta Count Sign 64 32 16 8 4 2 1 00h
17h R Sensor Input 8
Delta Count Sign 64 32 16 8 4 2 1 00h
TABLE 5-8: SENSITIV IT Y CONTROL REGISTER
Addr R/W Register B7 B6 B5 B4 B3 B2 B1 B0 Default
1Fh R/W Sensitivity Control - DELTA_SENSE[2:0] BASE_SHIFT[3:0] 2Fh
2013-2015 Microchip Technology Inc. DS00001571B-page 31
CAP1298
settings, the MSB of the Delta Count register corresponds to a delta count of 8192 counts
out of ~25,000 which corresponds to a touch of approximately 33% of the base capacitance
(or a C of 3.33pF from a 10pF base capacitance).
Bits 3 - 0 - BASE_SHIFT[3:0] - Controls the scaling and data presentation of the Base Count registers. The higher the
value of these bits, the larger the range and the lower the resolution of the data presented. The scale factor represents
the multiplier to the bit-weighting presented in these register descriptions.
APPLICATION NOTE: The BASE_SHIFT[3:0] bits normally do not need to be updated. These settings will not affect
touch detection or sensitivity. These bits are sometimes helpful in analyzi ng the Cap Sensing
board performance and stability.
TABLE 5-9: DELTA_SENSE BIT DECODE
DELTA_SENSE[2:0] Sensitivity Multiplier
210
0 0 0 128x (most sensitive)
001 64x
0 1 0 32x (default)
011 16x
100 8x
101 4x
110 2x
1 1 1 1x - (least sensitive)
TABLE 5-10: BASE_SHIFT BIT DECODE
BASE_SHIFT[3:0] Data Scaling Facto r
32 1 0
00 0 0 1x
00 0 1 2x
00 1 0 4x
00 1 1 8x
01 0 0 16x
01 0 1 32x
01 1 0 64x
0 1 1 1 128x
1 0 0 0 256x
All others 256x
(default = 1111b)
CAP1298
DS00001571B-page 32 2013-2015 Microchip Technology Inc.
5.6 Configuration Registers
The Configuration registers control general global functiona lity that affects the entire device.
5.6.1 CONFIGURATION - 20H
Bit 7 - TIMEOUT - Enables the timeout and idle functi onality of the SMBus protocol.
• ‘0’ (default) - The SMBus timeout and idle function ality are disabled. The SMBus interface will not time out if the
clock line is held low. Likewise, it will not reset if both the data and clock lines are held high for longer than 200us.
• ‘1’ - The SMBus timeout and idle functionality are enabled . The SMBus interface will reset if the clock line is held
low for longer than 30ms. Likewise, it will reset if both the data and clock lines are held high for longer than 200us.
Bit 5 - DIS_DIG_NOISE - Determines whether the digital noise threshold (see Section 5.20, "Sensor Input Noise Thresh-
old Register") is used by the device. Setting this bit disables the feature.
• ‘0’ - The digital noise threshold is used. If a delta count value exceeds the noise threshold but does not exceed the
touch threshold, the sample is discarded and not used for the automatic recalibration routin e.
• ‘1’ (default) - The noise threshold is disabled. Any delta count that is less than the touch threshold is used for the
automatic recalibration routine.
Bit 4 - DIS_ANA_NOISE - Determines whether the analog noise filter is enabled. Setting this bit disables the feature.
• ‘0’ (default) - If low frequency noise is detected by the analog block, the delta count on the corresponding channel
is set to 0. Note that this does not require that Nois e Status bits be set.
• ‘1’ - A touch is not blocked even if low frequency noise is detected.
Bit 3 - MAX_DUR_EN - Determines whether the maximum duration recalibration is enabled.
• ‘0’ (default) - The maximum duration recalibration functionality is disabled. A touch may be held indefinitely and no
recalibration will be performed on any sensor input.
• ‘1’ - The maximum duration recalibration functionality is enabled. If a touch is held for longer than the MAX_DUR
bit settings (see Section 5.8), the recalibration routine will be restarted (see Section 4.4.3, "Delayed Recalibra-
tion").
5.6.2 CONFIGURATION 2 - 44H
Bit 6 - BC_OUT_RECAL - Controls whether to retry analog calibration when the base count is out of limit for one or more
sensor inputs.
• ‘0’ - When the BC_OUTx bit is set for a sensor input, the out of limit base count will be used for the sensor input.
• ‘1’ (default) - When the BC_OUTx bit is set for a sensor input (see Section 5.17, "Base Count Out of Limit Regis-
ter"), analog calibration will be repeated on the sensor input.
Bit 5 - BLK_PWR_CTRL - Dete rmines whether the device will re duce power consump tion while waitin g between con-
version time completion and the end of the sensing cycle.
• ‘0’ (default) - The device will reduce power consumption during the time between the end of the last conversion
and the end of the sensing cycle.
• ‘1’ - The device will not reduce power consumption during the time between the end of the last conversion and the
end of the sensing cycle.
TABLE 5-11: CONFIGURATION REGISTERS
Addr R/W Register B7 B6 B5 B4 B3 B2 B1 B0 Default
20h R/W Configuration TIME
OUT -DIS_
DIG_
NOISE
DIS_
ANA_
NOISE MAX_
DUR_EN - - - 20h
44h R/W Configuration
2-BC_
OUT_
RECAL
BLK_
PWR_
CTRL
BC_
OUT_
INT
SHOW_
RF_
NOISE
DIS_
RF_
NOISE
ACAL
_FAIL
_INT
INT_
REL_
n40h
2013-2015 Microchip Technology Inc. DS00001571B-page 33
CAP1298
Bit 4 - BC_OUT_INT - Controls the interrupt behavior when the base count is out of limit for one or more sensor inputs.
• ‘0’ (defaul t) - An inte rru pt is no t ge n era t ed whe n th e BC _O U T bi t i s set (see Section 5.2, "Status Registers").
• ‘1’ - An interrupt is generated when the BC_OUT bit is set.
Bit 3 - SHOW_RF_NOISE - Determines whether the Noise Status bits will show RF Noise as the only input source.
• ‘0’ (default) - The Noise S t atus registers will show both RF noise and low frequency noise if either is detected on a
capacitive touch sensor input.
• ‘1’ - The Noise S t atus registers will only show RF noise if it is detected on a capacitive touch sensor input. Low fre-
quency noise will still be detected and tou ches will be blocked normally; however, the status bits will not be
updated.
Bit 2 - DIS_RF_NOISE - Determines whether the RF noise filter is enabled. Setting this bit disables the feature.
• ‘0’ (default) - If RF noise is detected by the analog block, the delta count on the corresponding channel is set to 0.
Note that this does not require that Noise Status bits be set.
• ‘1’ - A touch is not blocked even if RF noise is detected.
Bit 1 - ACAL_F AIL_INT - Controls the interrupt behavior when analog calibration fails for one or more sensor inputs (see
Section 4.4, "Sensor Input Calibration").
• ‘0’ (default) - An interrupt is not generated when the ACAL_FAIL bit is set (see Section 5.2, "Status Registers").
• ‘1’ - An interrupt is generated when the ACAL_FAIL bit is set
Bit 0 - INT_REL_n - Controls the interrupt behavior when a release is detected on a button (see Section 4.9.2, "Capac-
itive Sensor Input Interrupt Behavior").
• ‘0’ (default) - An interrupt is generated when a press is detected and again when a release is detected and at the
repeat rate (if enabled - see Section 5.12).
• ‘1’ - An interrupt is generated when a press is detected and at the repeat rate but not when a release is detected.
5.7 Sensor Input Enable Register
The Sensor Input Enable register determine s whether a capacitive touch sensor input is included in the sensing cycle
in the Active state.
For all bits in this register:
• ‘0’ - The specified input is not included in the sensing cycle in the Active state.
• ‘1’ (default) - The specified input is included in the sensing cycle in the Active state.
Bit 7 - CS8_EN - Determines whether the CS8 input is monitored in the Active state.
Bit 6 - CS7_EN - Determines whether the CS7 input is monitored in the Active state.
Bit 5 - CS6_EN - Determines whether the CS6 input is monitored in the Active state.
Bit 4 - CS5_EN - Determines whether the CS5 input is monitored in the Active state.
Bit 3 - CS4_EN - Determines whether the CS4 input is monitored in the Active state.
Bit 2 - CS3_EN - Determines whether the CS3 input is monitored in the Active state.
Bit 1 - CS2_EN - Determines whether the CS2 input is monitored in the Active state.
Bit 0 - CS1_EN - Determines whether the CS1 input is monitored in the Active state.
TABLE 5-12: SENSOR INPUT ENABLE REGISTER
AddrR/WRegister B7 B6B5B4B3B2B1B0Default
21h R/W Sensor Input
Enable CS8_EN CS7_EN CS6_EN CS5_EN CS4_EN CS3_EN CS2_EN CS1_EN FFh
CAP1298
DS00001571B-page 34 2013-2015 Microchip Technology Inc.
5.8 Sensor Input Configuration Register
The Sensor Input Configuration Register controls timings associated with the capacitive sensor inputs.
Bits 7 - 4 - MAX_DUR[3:0] - (default 1010b) - Determines the maximum time that a sensor pad is allowed to be touched
until the capacitive touch sensor input is recalibrated (see Section 4.4.3, "Delayed Recalibration"), as shown in Table 5-
14.
Bits 3 - 0 - RPT_RATE[3:0] - (default 0100b) Determines the time duration between interrupt assertions when auto
repeat is enabled (see Section 4.9.2, "Capacitive Sensor Input Interrupt Behavior"). The resolution is 35ms and the
range is from 35ms to 560ms as shown in Table 5-15.
TABLE 5-13: SENSOR INPUT CONFIGURATION REGISTER
AddrR/W Register B7B6B5B4B3B2B1B0Default
22h R/W Sensor Input
Configuration MAX_DUR[3:0] RPT_RATE[3:0] A4h
TABLE 5-14: MAX_DUR BIT DECODE
MAX_DUR[3:0] Time before Recalibration
32 1 0
0 0 0 0 560ms
0 0 0 1 840ms
0 0 1 0 1120ms
0 0 1 1 1400ms
0 1 0 0 1680ms
0 1 0 1 2240ms
0 1 1 0 2800ms
0 1 1 1 3360ms
1 0 0 0 3920ms
1 0 0 1 4480ms
1 0 1 0 5600ms (default)
1 0 1 1 6720ms
1 1 0 0 7840ms
1 1 0 1 8906ms
1 1 1 0 10080ms
1 1 1 1 11200ms
2013-2015 Microchip Technology Inc. DS00001571B-page 35
CAP1298
5.9 Sensor Input Configuration 2 Register
Bits 3 - 0 - M_PRESS[3:0] - (default 0111b) - Determines the minimum amount of time that sensor inputs configured to
use auto repeat must detect a sensor pad touch to detect a “press and hold” event (see Section 4.9.2, "Capacitive Sen-
sor Input Interrupt Behavior"). If the sensor input detects a touch for longe r than the M_PRESS[3:0 ] settings, a “press
and hold” event is detected. If a sensor input detects a touch for less than or equal to the M_PRESS[3:0] settings, a
touch event is detected.
The resolution is 35ms and the range is from 35ms to 560ms as shown in Table 5-17.
TABLE 5-15: RPT_RATE BIT DECODE
RPT_RATE[3:0] Interrupt Repeat Rate
3210
0000 35ms
0001 70ms
0 0 1 0 105ms
0 0 1 1 140ms
0 1 0 0 175ms (default)
0 1 0 1 210ms
0 1 1 0 245ms
0 1 1 1 280ms
1 0 0 0 315ms
1 0 0 1 350ms
1 0 1 0 385ms
1 0 1 1 420ms
1 1 0 0 455ms
1 1 0 1 490ms
1 1 1 0 525ms
1 1 1 1 560ms
TABLE 5-16: SENSOR INPUT CONFIGURATION 2 RE GISTER
AddrR/W Register B7B6B5B4B3B2B1B0Default
23h R/W Sensor Input
Configuration 2 - - - - M_PRESS[3:0] 07h
CAP1298
DS00001571B-page 36 2013-2015 Microchip Technology Inc.
5.10 Averaging and Sampling Configuration Register
The Averaging and Sampling Configuration register controls the number of samples t aken and the target sensing cycle
time for sensor inputs enabled in the Active state.
Bits 6 - 4 - AVG[2:0] - Determines the number of samples that are taken for all channels enabled in the Active state
during the sensing cycle as shown in Table 5-19. All samples are taken consecutively on the same channe l before the
next channel is samp led and the resu lt is averaged over the numbe r of samples measured before updating the mea-
sured results.
For example, if CS1, CS2, and CS3 are sampled during the sensing cycle, and the AVG[2:0] bits are set to take 4 sam-
ples per channel, then the full sensing cycle will be: CS1, CS1, CS1, CS1, CS2, CS2, CS2, CS2, CS3, CS3, CS3, CS3.
TABLE 5-17: M_PRESS BIT DECODE
M_PRESS[3:0] M_PRESS Settings
3210
0000 35ms
0001 70ms
0 0 1 0 105ms
0 0 1 1 140ms
0 1 0 0 175ms
0 1 0 1 210ms
0 1 1 0 245ms
0 1 1 1 280ms (default)
1 0 0 0 315ms
1 0 0 1 350ms
1 0 1 0 385ms
1 0 1 1 420ms
1 1 0 0 455ms
1 1 0 1 490ms
1 1 1 0 525ms
1 1 1 1 560ms
TABLE 5-18: AVERAGING AND SAMPLING CONFIGURATION REGISTER
Addr R/W Register B7 B6 B5 B4 B3 B2 B1 B0 Default
24h R/W Averaging and
Sampling
Config - AVG[2:0] SAMP_TIME[1:0] CYCLE_TIME
[1:0] 39h
2013-2015 Microchip Technology Inc. DS00001571B-page 37
CAP1298
Bits 3 - 2 - SAMP_TIME[1:0] - Determines the time to take a single sample as shown in Table 5-20. Sample time affects
the magnitude of the base co unts, as shown in Table 4 -1, "Ideal Base Counts".
Bits 1 - 0 - CYCLE_TIME[1:0] - Determines the desired sensing cycle time for channels enabled in the Active state, as
shown in Table 5-21. All enabled channels are sampled at the beginning of the sensing cycle. If additional time is
remaining, the device is placed into a lower power state for the remainder of the sensing cycl e.
TABLE 5-19: AVG BIT DECODE
AVG[2:0] Number Of Samples Taken Per
Measurement
210
000 1
001 2
010 4
0 1 1 8 (default)
100 16
101 32
110 64
1 1 1 128
TABLE 5-20: SAMP_TIME BIT DECODE
SAMP_TIME[1:0] Sample Time
10
0 0 320us
0 1 640us
1 0 1.28ms (default)
1 1 2.56ms
TABLE 5-21: CYCLE_TIME BIT DECODE
CYCLE_TIME[1:0] Progr a mmed Sensing Cycle Time
10
00 35ms
0 1 70ms (default)
1 0 105ms
1 1 140ms
CAP1298
DS00001571B-page 38 2013-2015 Microchip Technology Inc.
APPLICATION NOTE: The programmed sensing cycle time (CYCLE_TIME[1:0]) is only maintained if the actual time
to take the samples is less than the programmed cycle time. The AVG[2:0] bits will take
priority, so the sensing cycle time will be extended as necessary to accommodate the
number of samples to be measured.
5.10.1 CALIBRATION ACTIVATE AND STATUS REGISTER
The Calibration Activate and Status Register serves a dual function:
1. It forces the selected sensor inputs to be calibrated, affecting both the analog and digital blocks (see Section 4.4,
"Sensor Input Calibration"). When one or more bits are set, the device performs the calibration routine on the
corresponding sensor inputs. When the analog calibration routine is finished, the CALX[9:0] bits are updated (see
Section 5.28, "Sensor Input Calibration Registers"). If the analog calibrat ion routine completed successfully for a
sensor input, the corresponding bit is automatically cleared.
APPLICATION NOTE: In the case above, bits can be set by host or are automatically set by the device whenever
a sensor input is newly enabled (such as coming out of Deep Sleep, after power-on reset,
when a bit is set in the Sensor Enable Channel Enable register (21h) and the device is in
the Active state, or when a bit is set in the Standby Channel Enable Register (40h) and the
device is in the Standby state).
2. It serves as an indicator of an analog calibration fail ure. If any of the bits could not be cleared, the ACAL_FAIL
bit is set (see Section 5.2, "Status Registers"). A bit will fail to clear if a noise bit is set or if the calib ration val ue
is at the maximum or minimum value.
APPLICATION NOTE: In the case above, do not check the Calibration Activate and Status bits for failures unless
the ACAL_FAIL bit is set. In addition, if a sensor input is newly enabled, do not check the
Calibration Activate and Status bits until time has elapsed to complete calibration on the
sensor input. Otherwise, the ACAL_FAIL bit may be set for one sensor input, but the newly
enabled sensor input may still be set to ‘1’ in the Calibration Activate and Status, not because
it failed, but because it has not been calibrated yet.
For all bits in this register:
• ‘0’ - No action needed.
• ‘1’ - Writing a ‘1’, forces a calibration on the corresponding sensor input. If the ACAL_F AIL flag is set and this bit is
set (see application note above), the sensor input could not complete analog calibration.
Bit 7 - CS8_CAL - Bit for CS8 input.
Bit 6 - CS7_CAL - Bit for CS7 input.
Bit 5 - CS6_CAL - Bit for CS6 input.
Bit 4 - CS5_CAL - Bit for CS5 input.
Bit 3 - CS4_CAL - Bit for CS4 input.
Bit 2 - CS3_CAL - Bit for CS3 input.
Bit 1 - CS2_CAL - Bit for CS2 input.
Bit 0 - CS1_CAL - Bit for CS1 input.
APPLICATION NOTE: Writing a ‘0’ to clear a ‘1’ may cause a planned calibration to be skipped, if the calibration
routine had not reached the sensor input yet.
TABLE 5-22: CALIBRATION ACTIVATE AND STATUS REGISTER
AddrR/WRegisterB7 B6B5B4B3B2B1B0Default
26h R/W Calibration
Activate
and Status CS8_
CAL CS7_
CAL CS6_
CAL CS5_
CAL CS4_
CAL CS3_
CAL CS2_
CAL CS1_
CAL 00h
2013-2015 Microchip Technology Inc. DS00001571B-page 39
CAP1298
5.11 Interrupt Enable Register
The Interrupt Enable register determines whe ther a sensor pad touch or release (if ena bled) causes an interrupt (see
Section 4.9, "Interrupts").
For all bits in this register:
• ‘0’ - The ALERT# pin will not be asserted if a touch is detected on the specified sensor input.
• ‘1’ (default) - The ALERT# pin will be asserted if a touch is detected on the specified sensor input.
Bit 7 - CS8_INT_EN - Enables the ALERT# pin to be asserted if a touch is detected on CS8 (associated with the CS8
status bit).
Bit 6 - CS7_INT_EN - Enables the ALERT# pin to be asserted if a touch is detected on CS7 (associated with the CS7
status bit).
Bit 5 - CS6_INT_EN - Enables the ALERT# pin to be asserted if a touch is detected on CS6 (associated with the CS6
status bit).
Bit 4 - CS5_INT_EN - Enables the ALERT# pin to be asserted if a touch is detected on CS5 (associated with the CS5
status bit).
Bit 3 - CS4_INT_EN - Enables the ALERT# pin to be asserted if a touch is detected on CS4 (associated with the CS4
status bit).
Bit 2 - CS3_INT_EN - Enables the ALERT# pin to be asserted if a touch is detected on CS3 (associated with the CS3
status bit).
Bit 1 - CS2_INT_EN - Enables the ALERT# pin to be asserted if a touch is detected on CS2 (associated with the CS2
status bit).
Bit 0 - CS1_INT_EN - Enables the ALERT# pin to be asserted if a touch is detected on CS1 (associated with the CS1
status bit).
5.12 Repeat Rate Enable Register
The Repeat Rate Enable register enables the repeat rate of the sensor inputs as described in Section 4.9.2, "Capacitive
Sensor Input Interrupt Behavior" .
For all bits in this register:
• ‘0’ - The repeat rate for the speci fied sensor input is disabled. It will only generate an interrupt when a touch is
detected and when a release is detected (if enabled) no matter how long the touch is held.
• ‘1’ (default) - The repeat rate for the specified sensor input is enabled. In the case of a “touch” event, it will gener-
ate an interrupt when a touch is detected and a releas e is detected (as determined by the INT_REL_n bit - see
Section 5.6, "Configuration Registers"). In the case of a “press and hold” event, it will generate an interrupt when a
touch is detected and at the repeat rate so long as the touch is held.
Bit 7 - CS8_RPT_EN - Enables the repeat rate for capacitive touch sensor input 8.
TABLE 5-23: INTERRUPT ENABLE REGISTER
AddrR/WRegisterB7B6B5B4B3B2B1B0Default
27h R/W Interrupt
Enable CS8_
INT_EN CS7_
INT_EN CS6_
INT_EN CS5_
INT_EN CS4_
INT_EN CS3_
INT_EN CS2_
INT_EN CS1_
INT_EN FFh
TABLE 5-24: REPEAT RATE ENABLE REGISTER
AddrR/WRegisterB7B6B5B4B3B2B1B0Default
28h R/W Repeat Rate
Enable CS8_
RPT_EN CS7_
RPT_EN CS6_
RPT_EN CS5_
RPT_EN CS4_
RPT_EN CS3_
RPT_EN CS2_
RPT_EN CS1_
RPT_EN FFh
CAP1298
DS00001571B-page 40 2013-2015 Microchip Technology Inc.
Bit 6 - CS7_RPT_EN - Enables the repeat rate for capacitive touch sensor input 7.
Bit 5 - CS6_RPT_EN - Enables the repeat rate for capacitive touch sensor input 6.
Bit 4 - CS5_RPT_EN - Enables the repeat rate for capacitive touch sensor input 5.
Bit 3 - CS4_RPT_EN - Enables the repeat rate for capacitive touch sensor input 4.
Bit 2 - CS3_RPT_EN - Enables the repeat rate for capacitive touch sensor input 3.
Bit 1 - CS2_RPT_EN - Enables the repeat rate for capacitive touch sensor input 2.
Bit 0 - CS1_RPT_EN - Enables the repeat rate for capacitive touch sensor input 1.
5.13 Signal Guard Enable Register
The Signal Guard Enable register enables the signal guard for the specified sensor inputs as described in Section 4.5.1,
"Signal Guard". When the signal guard is enabled, CS5 is disabled.
For all bits in this register:
• ‘0’ (default) - The signal guard is disa bled for the specified sensor input.
• ‘1’ - The signal guard is enabled for the specified sensor input.
Bit 7 - CS8_SG_EN - Enables the signal guard for capacitive touch sensor input 8.
Bit 6 - CS7_SG_EN - Enables the signal guard for capacitive touch sensor input 7.
Bit 5 - CS6_SG_EN - Enables the signal guard for capacitive touch sensor input 6.
Bit 3 - CS4_SG_EN - Enables the signal guard for capacitive touch sensor input 4.
Bit 2 - CS3_SG_EN - Enables the signal guard for capacitive touch sensor input 3.
Bit 1 - CS2_SG_EN - Enables the signal guard for capacitive touch sensor input 2.
Bit 0 - CS1_SG_EN - Enables the signal guard for capacitive touch sensor input 1.
5.14 Multiple Touch Configuration Register
The Multiple Touch Configuration register controls the settings for the multiple touc h detection circuitry. These settings
determine the number of simultaneous buttons that may be pressed before additional buttons are blocked and the MUL T
status bit is set.
Bit 7 - MULT_BLK_EN - Enables the multiple button blocking circuitry.
• ‘0’ - The multiple touch circuitry is disabled. The device will not block multiple touches.
• ‘1’ (default) - The multiple touch circuitry is enabled. The device will flag the number of touches equal to pro-
grammed multiple touch threshold and block all others. It will remember which sensor inputs are valid and block all
others until that sensor pad has been released. Once a sensor pad has been released, the N detected touches
TABLE 5-25: SIG NAL GUARD ENABLE REGISTER
AddrR/WRegisterB7B6B5B4B3B2B1B0Default
29h R/W Signal
Guard
Enable CS8_
SG_EN CS7_
SG_EN CS6_
SG_EN -CS4_
SG_EN CS3_
SG_EN CS2_
SG_EN CS1_
SG_EN 00h
TABLE 5-26: MULTIPLE TOUCH CONFIGURATION
Addr R/W Register B7 B6 B5 B4 B3 B2 B1 B0 Default
2Ah R/W Multiple Touch
Config MULT_
BLK_
EN - - - B_MULT_T[1:0] - - 80h
2013-2015 Microchip Technology Inc. DS00001571B-page 41
CAP1298
(determined via the sensing cycle order of CS1 - CS8) will be flagged and all others blocked.
Bits 3 - 2 - B_MUL T_T[1:0] - Determines the number of simultaneous touches on all sensor pads before a Multiple Touch
Event is detected and sensor inputs are blocked. The bit decode is given by Table 5-27.
5.15 Multiple Touch Pattern Configuration Register
The Multiple Touch Pattern Configuration register controls the settings for the multiple touch pattern detection circuitry.
This circuitry works like the multiple touch detection circuitry with the following differences:
1. The detection threshold is a percentage of the touch detection threshold as defined by the MTP_TH[1:0] bits
whereas the multiple touch circuitry uses the touch detection threshold.
2. The MTP detection circuitry either w ill detect a specific pattern of sensor inputs as determined by the Multiple
Touch Pattern register settings or it will use the Multiple Touch Pattern register settings to determine a minimum
number of sensor inputs that will cause the MTP circuitry to flag an event (see Section 5.16, "Multiple Touch Pat-
tern Register"). When using pattern recognition mode, if all of the sensor inputs set by the Multiple Touch Pattern
register have a delta count greater than the MTP threshold or have their corresponding Noise Flag Status bits
set, the MTP bit will be set. When using the absolute number mode, if the number of sensor inputs with thresholds
above the MTP threshold or with Noise Fla g Status bits set i s equal to or greater t han th is numb er, the MTP bit
will be set.
3. When an MTP event occurs, all touches are blocked and an interrupt is generated.
4. All sensor inputs will remain blocked so long as the requisite number of sensor inputs are above the MTP thresh-
old or have Noise Flag S tatus bits set. Once this condition is removed, touch detection will be restored. Note that
the MTP status bit is only cleared by writing a ‘0’ to the INT bit once the condition has been removed.
Bit 7 - MTP_EN - Enables the multiple touch pattern detection circuitry.
• ‘0’ (default) - The MTP detection circuitry is disabled.
• ‘1’ - The MTP detection circuitry is enabled.
Bits 3 - 2 - MTP_TH[1:0] - Determine the MTP threshold, as shown in Table 5-29. This threshold is a percentage of sen-
sor input threshold (see Section 5.19, "Sensor Input Threshold Regi sters") for inputs enabled in the Active state or of
the standby threshold (see Secti on 5.24, "Standby Thre shold Register") for inputs enabled in the Standby state.
TABLE 5-27: B_MULT_T BIT DECODE
B_MULT_T[1:0] Number of Simultaneous Touches
10
0 0 1 (default)
01 2
10 3
11 4
TABLE 5-28: MULTIPLE TOUCH PATTERN CONFIGURATION
Addr R/W Register B7 B6 B5 B4 B3 B2 B1 B0 Default
2Bh R/W Multiple Touch
Pattern Config MTP_ EN - - - MTP_TH[1:0] COMP_
PTRN MTP_
ALERT 00h
CAP1298
DS00001571B-page 42 2013-2015 Microchip Technology Inc.
Bit 1 - COMP_PTRN - Determines whether the MTP detection circuitry will use the Multiple Touch Pattern register as a
specific pattern of sensor inputs or as an absolute number of sensor inputs.
• ‘0’ (default) - The MTP detection circuitry will use the Multiple Touch Pattern register bit settings as an absolute
minimum number of sensor inputs that must be above the threshold or have Noise Flag Status bits set. The num-
ber will be equal to the number of bits set in the register.
• ‘1’ - The MTP detection circuitry will use pattern recognition. Each bit set in the Multiple Touch Pattern register
indicates a specific sensor input that must have a delta count greater than the MTP threshold or have a Noise Flag
Status bit set. If the criteria are met, the MTP status bit will be set.
Bit 0 - MTP_ALERT - Enables an interrupt if an MTP event occurs. In either condition, the MTP status bit will be set.
• ‘0’ (default) - If an MTP event occurs, the ALERT# pin is not asserted.
• ‘1’ - If an MTP event occurs, the ALERT# pin will be asserted.
5.16 Multiple Touch Pattern Register
The Multiple Touch Pattern register acts as a pattern to identify an expected sensor input profile for diagnostics or other
significant events. There are two methods for how the Multiple Touch Pattern register is used: as specific sensor inputs
or number of sensor input that must exceed the MTP threshold or have Noise Flag Status bit s set. Which method is used
is based on the COMP_PTRN bit (see Section 5.15). The methods are descri bed below.
1. Specific Sensor Inputs: If, during a single sensing cycle, the specific sensor inputs above the MTP threshold or
with Noise Flag Status bits set match those bits set in the Multiple Touch Pattern register, an MTP event is
flagged.
2. Number of Sensor Inputs: If, during a single sensing cycle, the number of sensor inputs with a delta count above
the MTP threshold or with Noise Flag S t atus bits set is equal to or greater than the number of pattern bits set, an
MTP event is flagged.
For all bits in this register:
• ‘0’ - The specified sensor input is not considered a part of the pattern.
• ‘1’ - The specified sensor input is considered a part of the pattern, or the absolute number of sensor inputs that
must have a delta count greater than the MTP threshold or have the Noise Flag Status bit set is increased by 1.
Bit 7 - CS8_PTRN - Determines whether CS8 is considered as part of the Multiple Touch Pattern.
Bit 6 - CS7_PTRN - Determines whether CS7 is considered as part of the Multiple Touch Pattern.
TABLE 5-29: MTP_TH BIT DECODE
MTP_TH[1:0] Threshold Divide Setting
10
0 0 12.5% (default)
0125%
1 0 37.5%
1 1 100%
TABLE 5-30: MULTIPLE TOUCH PATTERN REGISTER
Addr R/W Register B7 B6 B5 B4 B3 B2 B1 B0 Default
2Dh R/W Multiple
Touch
Pattern CS8_
PTRN CS7_
PTRN CS6_
PTRN CS5_
PTRN CS4_
PTRN CS3_
PTRN CS2_
PTRN CS1_
PTRN FFh
2013-2015 Microchip Technology Inc. DS00001571B-page 43
CAP1298
Bit 5 - CS6_PTRN - Determines whether CS6 is considered as part of the Multiple Touch Pattern.
Bit 4 - CS5_PTRN - Determines whether CS5 is considered as part of the Multiple Touch Pattern.
Bit 3 - CS4_PTRN - Determines whether CS4 is considered as part of the Multiple Touch Pattern.
Bit 2 - CS3_PTRN - Determines whether CS3 is considered as part of the Multiple Touch Pattern.
Bit 1 - CS2_PTRN - Determines whether CS2 is considered as part of the Multiple Touch Pattern.
Bit 0 - CS1_PTRN - Determines whether CS1 is considered as part of the Multiple Touch Pattern.
5.17 Base Count Out of Limit Register
The Base Count Out of Limit Register indicates which sensor inputs have base counts out of limit (see Section 4.4, "Sen-
sor Input Calibration"). When these bi ts are set, the BC_OUT bi t i s set (s ee Section 5.2, "Status Registers").
For all bits in this register:
• ‘0’ - The base count for the specified sensor input is in the operating range.
• ‘1’ - The base count of the specified sens or input is not in the operating range.
Bit 7 - BC_OUT_8 - Indicates whether CS8 has a base count ou t of limit.
Bit 6 - BC_OUT_7 - Indicates whether CS7 has a base count ou t of limit.
Bit 5 - BC_OUT_6 - Indicates whether CS6 has a base count ou t of limit.
Bit 4 - BC_OUT_5 - Indicates whether CS6 has a base count ou t of limit.
Bit 3 - BC_OUT_4 - Indicates whether CS6 has a base count ou t of limit.
Bit 2 - BC_OUT_3 - Indicates whether CS3 has a base count ou t of limit.
Bit 1 - BC_OUT_2 - Indicates whether CS2 has a base count ou t of limit.
Bit 0 - BC_OUT_1 - Indicates whether CS1 has a base count ou t of limit.
5.18 Recalibration Configuration Register
The Recalibration Configuration register controls some recalibration routine settings (see Section 4.4, "Sensor Input
Calibration") as well as advanced controls to program the Sensor Input Threshold register settings.
Bit 7 - BUT_LD_TH - Enables setting all Sensor Input Threshold registers by writing to the Sensor Input 1 Thresho ld
register.
• ‘0’ - Each Sensor Input X Threshold register is updated individually.
• ‘1’ (default) - Writing the Sensor Input 1 Threshold register will automatically overwrite the Sensor Input Threshold
registers for all sensor inputs (Sensor Input Threshold 1 through Sensor Input Threshold 8). The individual Sensor
Input X Threshold registers (Sensor Input 2 Thresh old through Sensor Input 8 Threshold) can be individually
updated at any time.
TABLE 5-31: BASE COUNT OUT OF LIMIT REGISTER
AddrR/WRegisterB7B6B5B4B3B2B1B0Default
2Eh R Base Count
Out of Limit BC_
OUT_
8
BC_
OUT_
7
BC_
OUT_
6
BC_
OUT_
5
BC_
OUT_
4
BC_
OUT_
3
BC_
OUT_
2
BC_
OUT_
100h
TABLE 5-32: RECALIBRATION CONFIGURATION REGISTERS
Addr R/W Register B7 B6 B5 B4 B3 B2 B1 B0 Default
2Fh R/W Recalibration
Configuration BUT_
LD_TH NO_CLR
_INTD NO_CLR
_NEG NEG_DELTA_
CNT[1:0] CAL_CFG[2:0] 8Ah
CAP1298
DS00001571B-page 44 2013-2015 Microchip Technology Inc.
Bit 6 - NO_CLR_INTD - Controls whether the accumulation of intermediate data is cleared if the noise status bit is set.
• ‘0’ (default) - The accumulation of interme diate data is cleared if the noise status bit is set.
• ‘1’ - The accumulation of intermediate data is not cleared if the noise status bit is set.
APPLICATION NOTE: Bits 5 and 6 should both be set to the same value. Either both should be set to ‘0’ or both
should be set to ‘1’.
Bit 5 - NO_CLR_NEG - Controls whether the consecutive negative delta counts counter is cleared if the noise status bit
is set.
‘0’ (default) - The consecutive negative delta counts counter is cleared if the noise status bit is set.
‘1’ - The consecutive negative delta counts counter is not cleared if the noise status bit is set.
Bits 4 - 3 - NEG_DELTA_CNT[1:0] - Determines the number of negative delta counts necessary to trigger a digital reca-
libration (see Section 4.4.2, "Negative Delta Count Recalibration"), as shown in Table 5-33.
Bits 2 - 0 - CAL_CFG[2:0] - Determines the update time and nu mber of samp les of th e automatic recalibratio n routine
(see Section 4.4.1, "Automatic Recalibration"). The settings apply to all sensor inputs universally (though individual sen-
sor inputs can be configured to support recalibration - see Section 5.10.1).
Note 5-1 Recalibration Samples refers to the number of samples that are measured and averaged before the
Base Count is updated however does not control the base count update period.
TABLE 5-33: NEG_DELTA_CNT BIT DECODE
NEG_DELTA_CNT[1:0] Nu mber of Consecutive Negative Delta Count Values
10
00 8
0 1 16 (default)
10 32
1 1 None (disabled)
TABLE 5-34: CAL_CFG BIT DECODE
CAL_CFG[2:0] Recalibration Samples
(see Note 5-1) Up date Time (see
Note 5-2)
210
0 0 0 16 16
001 32 32
0 1 0 64 64 (default)
0 1 1 128 128
100 256 256
1 0 1 256 1024
1 1 0 256 2048
1 1 1 256 4096
2013-2015 Microchip Technology Inc. DS00001571B-page 45
CAP1298
Note 5-2 Update Time refers to the amount of time (in sensing cycle periods) that elapses before the Base
Count is updated. The time will dep end upon the number of channe ls enabled, the averaging setting,
and the programmed sensing cycle time.
5.19 Sensor Input Threshold Registers
The Sensor Input Threshol d reg isters store the de lta threshol d that is used to determi ne if a tou ch has been detected.
When a touch occurs, the input signal of the corresponding sensor pad changes due to the capacitance associated with
a touch. If the sensor input change exceeds the threshold settings, a touch is detected.
When the BUT_LD_TH bit is set (see Section 5.18 - bit 7), writing data to the Sensor Input 1 Threshold register will
update all of the Sensor Input Threshold registe rs (31h - 37h inclusive).
5.20 Sensor Input Noise Threshold Register
The Sensor Input Noise Threshold register controls the value of a secondary internal threshold to detect noise and
improve the automatic recalibration routine. If a capacitive touch sensor input exceeds the Sensor Input Noise Threshold
but does not exceed the sensor input threshold, it is determined to be caused by a noise spike. That sample is not used
by the automatic recalibration routine. This fe ature can be disabled by setting the DIS_DIG_NOISE bit.
Bits 1-0 - CS1_BN_TH[1:0] - Controls the noise threshold for all capacitive touch sensor inputs, as shown in Table 5-3.
The threshold is proportional to the threshold setting.
TABLE 5-1: SENSOR INPUT THRESHOLD REGISTERS
AddrR/W Register B7B6B5B4B3B2B1B0Default
30h R/W Sensor Input 1
Threshold -6432168421 40h
31h R/W Sensor Input 2
Threshold -6432168421 40h
32h R/W Sensor Input 3
Threshold -6432168421 40h
33h R/W Sensor Input 4
Threshold -6432168421 40h
34h R/W Sensor Input 5
Threshold -6432168421 40h
35h R/W Sensor Input 6
Threshold -6432168421 40h
36h R/W Sensor Input 7
Threshold -6432168421 40h
37h R/W Sensor Input 8
Threshold -6432168421 40h
TABLE 5-2: SENSOR INPUT NOISE THRESHOLD REGISTER
AddrR/W Register B7B6B5B4B3B2B1B0Default
38h R/W Sensor Input
Noise Threshold ------
CS_BN_TH
[1:0] 01h
CAP1298
DS00001571B-page 46 2013-2015 Microchip Technology Inc.
5.21 Standby Channel Register
The S tandby Channel register controls which (if any) capacitive touch sensor inputs are enabled in Standby (see Section
4.3.1.2, "Standby State Sensing Settings").
For all bits in this register:
• ‘0’ (default) - The specified channel will not be monitored in Standby.
• ‘1’ - The specified channel will be monitored in Standby. It will use the standby threshold setting, and the standby
averaging and sensitivity settings.
Bit 7 - CS8_STBY - Controls whether the CS8 channel is enabled in Standby.
Bit 6 - CS7_STBY - Controls whether the CS7 channel is enabled in Standby.
Bit 5 - CS6_STBY - Controls whether the CS6 channel is enabled in Standby.
Bit 4 - CS5_STBY - Controls whether the CS5 channel is enabled in Standby.
Bit 3 - CS4_STBY - Controls whether the CS4 channel is enabled in Standby.
Bit 2 - CS3_STBY - Controls whether the CS3 channel is enabled in Standby.
Bit 1 - CS2_STBY - Controls whether the CS2 channel is enabled in Standby.
Bit 0 - CS1_STBY - Controls whether the CS1 channel is enabled in Standby.
5.22 Standby Configuration Register
The S tandby Configuration register controls averaging and sensing cycle time for sensor inputs enabled in S tandby . This
register allows the user to change averaging and sample times on a limited number of sensor inputs in Standby and still
maintain normal functionality in the Active state.
TABLE 5-3: CSX_BN_TH BIT DECODE
CS_BN_TH[1:0] Percent Threshold Setting
10
0025%
0 1 37.5% (default)
1050%
1 1 62.5%
TABLE 5-4: STANDBY CHANNEL REGISTER
AddrR/W Register B7 B6 B5B4B3B2B1B0Default
40h R/W Standby
Channel CS8_
STBY CS7_
STBY CS6_
STBY CS5_
STBY CS4_
STBY CS3_
STBY CS2_
STBY CS1_
STBY 00h
TA BLE 5-5: STANDBY CONFIGURATION REGISTER
Addr R/W Register B7 B6 B5 B4 B3 B2 B1 B0 Default
41h R/W Standby
Configuration AVG_
SUM STBY_AVG[2:0] STBY_SAMP_
TIME[1:0] STBY_CY_TIME
[1:0] 39h
2013-2015 Microchip Technology Inc. DS00001571B-page 47
CAP1298
Bit 7 - AVG_SUM - Determines whether the sensor inputs enabled in Standby will average the programmed number of
samples or whether they will accumulate for the progra mmed number of samp les.
• ‘0’ - (default) - The Standby enabled sensor input delta count values will be base d on the average of the pro-
grammed number of samples when compared against the threshold.
• ‘1’ - The Standby enabled sensor input delta count values will be based on the summation of the progra mmed
number of samples when compared against the threshold. Caution should be used with this setting as a touch
may overflow the delta count registers and may result in false readings.
Bits 6 - 4 - STBY_AVG[2:0] - Determines the number of samples that are taken for all Standby enabled channels during
the sensing cycle as shown in Table 5-6. All samples are taken consecutively on the same channel before the next chan-
nel is sampled and the result is averaged over the number of samples measured before updating the measured results.
Bit 3 - 2 - STBY_SAMP_TIME[1:0] - Determines the time to take a single sample for sensor inputs enabled in Standby
as shown in Table 5-7.
Bits 1 - 0 - STBY_CY_TIME[2:0] - Determines the desired sensing cycle time for sensor inputs enabled during S t andby,
as shown in Table 5-8. This control is al so used to determine programmed cycle time in the Combo state (see Section
4.3.1.3, "Combo State Sensing Settings" ). All enabled channels are sampled a t the beginning of the sensing cycle. If
additional time is remaining, the device is placed into a lower power state for the remainder of the sensing cycle.
TABLE 5-6: STBY_AVG BIT DECODE
STBY_AVG[2:0] Number Of Samples Tak en Per
Measurement
210
000 1
001 2
010 4
0 1 1 8 (default)
100 16
101 32
110 64
1 1 1 128
TABLE 5-7: STBY_SAMP_TIME BIT DECODE
STBY_SAMP_TIME[1:0] Sampling Time
10
0 0 320us
0 1 640us
1 0 1.28ms (default)
1 1 2.56ms
CAP1298
DS00001571B-page 48 2013-2015 Microchip Technology Inc.
APPLICATION NOTE: The programmed sensing cycle time (STDBY_CY_TIME[1:0] is only maintained if the actual
time to take the samples is less than the programmed cycle time. The STBY_AVG[2:0] bits
will take priority, so the sensing cycle time will be extended as necessary to accommodate
the number of samples to be measured.
5.23 Standby Sensitivity Register
The Standby Sensitivity register contro ls the sensitivity for sensor inputs enabled in Standby.
Bits 2 - 0 - STBY_SENSE[2:0] - Controls the sensitivity for sensor inputs that are enabled in Standby. The sensitivity
settings act to scale the relative delta count value higher or lower based on the system parameters. A setting of 000b is
the most sensitive while a setting of 111b is the least sensitive. At the more sensitive settings, touches are detected for
a smaller delta capacitance corresponding to a “lighter” touch. These setting s are more sensit ive to noise, how ever , and
a noisy environment may flag more false touches than higher sensitivity levels.
APPLICATION NOTE: A value of 128x is the most sensitive setting available. At the most sensitivity settings, the
MSB of the Delta Count register re presents 64 out of ~25,000 which co rresponds to a touch
of approximately 0.25% of the base capacitance (or a C of 25fF from a 10pF base
capacitance). Conversely a value of 1x is the least sensitive setting available. At these
settings, the MSB of the Delta Count register corresponds to a delta count of 8192 counts
out of ~25,000 which corresponds to a touch of approximately 33% of the base capacitance
(or a C of 3.33pF from a 10pF base capacitance).
TABLE 5-8: STBY_CY_TIME BIT DECODE
STBY_CY_TIME[1:0] Programmed Sensing Cycle Time
10
00 35ms
0 1 70ms (default)
1 0 105ms
1 1 140ms
TABLE 5-9: STANDBY SENSITIVITY REGISTER
AddrR/W Register B7 B6B5B4B3B2B1B0Default
42h R/W Standby
Sensitivity - - - - - STBY_SENSE[2:0] 02h
TABLE 5-10: STBY_SENSE BIT DECODE
STBY_SENSE[2:0] Sensitivity Multip lier
210
0 0 0 128x (most sensitive)
001 64x
0 1 0 32x (default)
2013-2015 Microchip Technology Inc. DS00001571B-page 49
CAP1298
5.24 Standby Threshold Register
The S tandby Threshold register stores the delta threshold that is used to determine if a touch has been detected. When
a touch occurs, the input signal of the corresponding sensor pad changes due to the capacitance associated with a
touch. If the sensor input change exceeds the threshold settings, a touch is detected.
5.25 Sensor Input Base Count Registers
011 16x
100 8x
101 4x
110 2x
1 1 1 1x - (least sensitive)
TABLE 5-11: STANDBY THRESHOLD REGISTER
AddrR/W Register B7B6B5B4B3B2B1B0Default
43h R/W Standby
Threshold -6432168421 40h
TABLE 5-12: SENSOR INPUT BASE COUNT REGISTERS
AddrR/W Register B7B6B5B4B3B2B1B0Default
50h R Sensor Input 1
Base Count 128 64 32 16 8 4 2 1 C8h
51h R Sensor Input 2
Base Count 128 64 32 16 8 4 2 1 C8h
52h R Sensor Input 3
Base Count 128 64 32 16 8 4 2 1 C8h
53h R Sensor Input 4
Base Count 128 64 32 16 8 4 2 1 C8h
54h R Sensor Input 5
Base Count 128 64 32 16 8 4 2 1 C8h
55h R Sensor Input 6
Base Count 128 64 32 16 8 4 2 1 C8h
56h R Sensor Input 7
Base Count 128 64 32 16 8 4 2 1 C8h
57h R Sensor Input 8
Base Count 128 64 32 16 8 4 2 1 C8h
TABLE 5-10: STBY_SENSE BIT DECODE (CONTINUED)
STBY_SENSE[2:0] Sensitivity Multip lier
210
CAP1298
DS00001571B-page 50 2013-2015 Microchip Technology Inc.
The Sensor Input Base Count registers store the calibrated “not touched” input value from the capacitive touch sensor
inputs. These registers are periodically updated by the calibration and recalibration routines.
The routine uses an internal adder to add the current count value for each reading to the sum of the previous readings
until sample size has been reached. At this point, the upper 16 bits are taken and used as the Sensor Input Base Count.
The internal adder is then reset and the recalibration routine continues.
The data presented is determined by the BASE_SHIFT[3:0] bits (see Section 5.5).
5.26 Power Button Register
The Power Button Reg ister indicates the sensor i nput that has been designated as the power button (see Section 4.6,
"Power Button").
Bits 2 - 0 - PWR_BTN[2:0] - When the power button feature is enabled, this control indicates the sensor input to be used
as the power button. The decode is shown in Table 5-14.
5.27 Power Button Configuration Register
The Power Button Configu ration Register con trols the len gth of ti me th at the designated powe r button must indi cate a
touch before an interrupt is generated and the power status indicator is set (see Section 4.6, "Power Button").
TABLE 5-13: POWER BUTTON REGISTER
AddrR/W Register B7B6B5B4B3B2B1B0Default
60h R/W Power Button - - - - - PWR_BTN[2:0] 00h
TABLE 5-14: PWR_BTN BIT DECODE
PWR_BTN[2:0] Senso r Inp ut Designated as Power Button
210
000 CS1
001 CS2
010 CS3
011 CS4
100 CS5
101 CS6
110 CS7
111 CS8
TABLE 5-15: POWER BUTTON CONFIGURATION REGISTER
AddrR/WRegister B7 B6B5B4B3 B2 B1 B0Default
61h R/W Power Button
Configuration -STBY_
PWR_
EN STBY_PWR_
TIME [1:0] -PWR_
EN PWR_TIME [1:0] 22h
2013-2015 Microchip Technology Inc. DS00001571B-page 51
CAP1298
Bit 6 - STBY_PWR_EN - Enables the power button feature in the Standby state.
• ‘0’ (default) - The Standby power button circuitry is disabled.
• ‘1’ - The Standby power button circuitry is enabled.
Bits 5 - 4 - STBY_PWR_TIME[1:0] - Determines the ove rall time, as shown in Table 5-16, that the power button must
be held in the Standby state, in order for an interrupt to be generated and the PWR bit to be set.
Bit 2 - PWR_EN - Enables the power button feature in the Active state.
• ‘0’ (default) - The power button circuitry is disabled in the Active state.
• ‘1’ -The power button circuitry is enabled in the Active state.
Bits 1 - 0 - PWR_TIME[1:0] - Determines the overall time, as shown i n Table 5-16, th at th e power b utto n must be he ld
in the Active state, in order for an interrupt to be generated and the PWR bit to be set.
5.28 Sensor Input Calibration Registers
TABLE 5-16: POWER BUTTON TIME BITS DECODE
PWR_TIME[1:0] / STBY_PWR_TIME[1:0] Power Button Touch Hold Time
10
0 0 280ms
0 1 560ms
1 0 1.12 sec (default)
1 1 2.24 sec
TABLE 5-17: SENSOR INPUT CALIBRATION REGISTERS
Addr Register R/W B7 B6 B5 B4 B3 B2 B1 B0 Default
B1h Sensor Input 1
Calibration R CAL1_9 CAL1_8 CAL1_7 CAL1_6 CAL1_5 CAL1_4 CAL1_3 CAL1_2 00h
B2h Sensor Input 2
Calibration R CAL2_9 CAL2_8 CAL2_7 CAL2_6 CAL2_5 CAL2_4 CAL2_3 CAL2_2 00h
B3h Sensor Input 3
Calibration R CAL3_9 CAL3_8 CAL3_7 CAL3_6 CAL3_5 CAL3_4 CAL3_3 CAL3_2 00h
B4h Sensor Input 4
Calibration R CAL4_9 CAL4_8 CAL4_7 CAL4_6 CAL4_5 CAL4_4 CAL4_3 CAL4_2 00h
B5h Sensor Input 5
Calibration R CAL5_9 CAL5_8 CAL5_7 CAL5_6 CAL5_5 CAL5_4 CAL5_3 CAL5_2 00h
B6h Sensor Input 6
Calibration R CAL6_9 CAL6_8 CAL6_7 CAL6_6 CAL6_5 CAL6_4 CAL6_3 CAL6_2 00h
B7h Sensor Input 7
Calibration R CAL7_9 CAL7_8 CAL7_7 CAL7_6 CAL7_5 CAL7_4 CAL7_3 CAL7_2 00h
B8h Sensor Input 8
Calibration R CAL8_9 CAL8_8 CAL8_7 CAL8_6 CAL8_5 CAL8_4 CAL8_3 CAL8_2 00h
CAP1298
DS00001571B-page 52 2013-2015 Microchip Technology Inc.
The Sensor Input Calibratio n registers hold the 10-bit value that represents the last calibration value. The value rep-
resents the capacit ance applied to the internal sensing circuits to balance the capacit ance of the sensor input pad. Min-
imum (000h) and maximum (3FFh) values indicate analog calibration failure (see Section 4.4, "Sensor Input
Calibration").
5.29 Calibration Sensitivity Configuration Registers
CALSENx[1:0] - Controls the gain used by the calibration routine to enable sensor inputs to be more sensitive for prox-
imity detection. Gain is based on capacitance touch pad capacitance ranges, as shown in Table 5-19. Since each sensor
input can have a different pad capacitance, each sensor input has a control.
5.30 Product ID Register
B9h Sensor Input
Calibration
LSB 1 R CAL4_1 CAL4_0 CAL3_1 CAL3_0 CAL2_1 CAL2_0 CAL1_1 CAL1_0 00h
BAh Sensor Input
Calibration
LSB 2 R CAL8_1 CAL8_0 CAL7_1 CAL7_0 CAL6_1 CAL6_0 CAL5_1 CAL5_0 00h
TAB LE 5-18: CALIB RATION SENSITIVITY CONFIGURATION REGISTERS
AddrRegisterR/WB7B6B5B4B3B2B1B0Default
80h Calibration
Sensitivity
Config 1 R/W CALSEN4[1:0] CALSEN3[1:0] CALSEN2[1:0] CALSEN1[1:0] 00h
81h Calibration
Sensitivity
Config 2 R/W CALSEN8[1:0] CALSEN7[1:0] CALSEN6[1:0] CALSEN5[1:0] 00h
TABLE 5-19: CALSENX BIT DECODE
CALSENx[1:0] Gain Capacitive Touch Pad Capacitan c e
Range
10
0 0 1 5-50pF (default)
012 0-25pF
1 0 4 0-12.5pF
TAB LE 5-20: PRODUCT ID REGISTER
AddrR/W Register B7B6B5B4B3B2B1B0Default
FDh R Product ID
CAP1298 01110001 71h
T
ABLE 5-17: SENSOR INPUT CALIBRATION REGISTERS (CONTINUED)
Addr Register R/W B7 B6 B5 B4 B3 B2 B1 B0 Default
2013-2015 Microchip Technology Inc. DS00001571B-page 53
CAP1298
The Product ID register stores a unique 8-bit value that identifies the device.
5.31 Manufacturer ID Register
The Vendor ID register stores an 8-bit value that represents MCHP.
5.32 Revision Register
The Revision register stores an 8-bit value that represents the part revision.
TABLE 5-21: VENDOR ID REGISTER
AddrR/W Register B7B6B5B4B3B2B1B0Default
FEh RManufacturer ID01011101 5Dh
TABLE 5-22: REVISION REGISTER
AddrR/W Register B7B6B5B4B3B2B1B0Default
FFhR Revision 00000000 00h
CAP1298
DS00001571B-page 54 2013-2015 Microchip Technology Inc.
6.0 PACKAGE INFORMATION
6.1 CAP1298 Package Drawings
FIGURE 6-1: CAP1298 14-LEAD PLASTIC SMALL OUTLINE, NARROW, 3.90 MM BODY (SOIC)
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
2013-2015 Microchip Technology Inc. DS00001571B-page 55
CAP1298
FIGURE 6-1: CAP1298 14-LEAD PLASTIC SMALL OUTLINE, NARROW, 3.90 MM BODY (SOIC)
Note: For the most current package drawings, please see the Microchip Packaging Specification located at
http://www.microchip.com/packaging
CAP1298
DS00001571B-page 56 2013-2015 Microchip Technology Inc.
FIGURE 6-1: CAP1298 14-LEAD PLASTIC SMALL OUTLINE, NARROW, 3.90 MM BODY (SOIC)
1RWH )RUWKHPRVWFXUUHQWSDFNDJHGUDZLQJVSOHDVHVHHWKH0LFURFKLS3DFNDJLQJ6SHFLILFDWLRQORFDWHGDW
KWWSZZZPLFURFKLSFRPSDFNDJLQJ
2013-2015 Microchip Technology Inc. DS00001571B-page 57
CAP1298
FIGURE 6-2: CAP1298 16-PIN QFN 3MM X 3MM
CAP1298
DS00001571B-page 58 2013-2015 Microchip Technology Inc.
FIGURE 6-3: CAP1298 PACKAGE DIMENSIONS - 16-PIN QFN 3MM X 3MM
2013-2015 Microchip Technology Inc. DS00001571B-page 59
CAP1298
FIGURE 6-4: CAP1298 PCB LAND PATTERN AND STENCIL - 16-PIN QFN 3MM X 3MM
CAP1298
DS00001571B-page 60 2013-2015 Microchip Technology Inc.
6.2 Package Marking
FIGURE 6-5: CAP1298 PACKAGE MARKING
3 6 W W
N N N A
PIN1
CAP1298Ͳ1ͲSLͲTR CAP1298Ͳ2ͲSLͲTR CAP1298Ͳ1ͲA4ͲTR CAP1298Ͳ2ͲA4ͲTR
36W
NNNA
e3
TOP
BOTTOM
Bottommarkingnotallowed
PBͲFREE/GREENSYMBOL
(Ni/PdPPͲLF)
PIN1
2x0.6
Line1–DeviceCode,Week
Line2–AlphanumericTraceabilityCode
W
Lines1Ͳ2:
Line3:
CenterHorizontalAlignment
AsShown
H5W
NNNA
e3
TOP
BOTTOM
Bottommarkingnotallowed
PBͲFREE/GREENSYMBOL
(Ni/PdPPͲLF)
PIN1
2x0.6
Line1–DeviceCode,Week
Line2–AlphanumericTraceabilityCode
W
Lines1Ͳ2:
Line3:
CenterHorizontalAlignment
AsShown
Line1–DeviceCode,Week
Line2–AlphanumericTraceabilityCode
Line1–DeviceCode,Week
Line2–AlphanumericTraceabilityCode
H 5 W W
N N N A
PIN1
PbͲFreeJEDEC®designatorforMatteTin(Sn)
PbͲFreeJEDEC®designatorforMatteTin(Sn)
2013-2015 Microchip Technology Inc. DS00001571B-page 61
CAP1298
APPENDIX A: DEVICE DELT A
A.1 Delta from CAP1128 / CAP1188 to CAP1298
1. Revision ID set to 00h.
2. Pinout changed. RESET, WAKE, and ADDR_COMM pins removed. LED pins removed. SPI pins / muxing also
removed. Added GND pin as ground slug is no longer used for ground connection.
3. Reduced package size from a 20-pin 4mm x 4mm QFN to a 16-pin 3mm x 3mm QFN.
4. Added Power Button feature (see Se ction 4.6, "Power Button").
5. Added ACAL_FAIL bit to flag analog calibration failures (see Section 5.2, "Status Registers") and ACAL_-
FA IL_INT bit to control analog calibration failure interrupts (see Section 5.6, "Configuration Registers").
6. Added BC_OUT bit to flag calibration failures regarding base counts out of limit (see Section 5.2, "Status Regis-
ters") and BC_OUT_RECAL and BC_OUT_INT bit to control base count out of limit behavior and interrupts (see
Section 5.6, "Configuration Registers"). Added Base Count Out of Limit Register to indicate which sensor inputs
have base counts outside the operating range (see Section 5.17, "Base Count Out of Limit Register").
7. New Combo state has been added which allows some sensors programmed to use the Active state settings and
other sensors programmed to use the Standby state settings to function at the same time (see Section 4.3.1.3,
"Combo State Sensing Settings").
8. Added an option for a signal guard that is overloaded with the CS5 pin. This signal guard is configured to power
a ground shield for improved signa l in certain applications (see Se ction 4.5.1, "Signal Guard").
9. Increased supply voltage range for 5V operation.
10. Increased operating temperature range from 0°C - 85°C to -40°C to 125°C.
11. LEDs removed.
12. SMBus address fixed at 0101_000(r/w).
13. Removed SPI communications protocol option.
14. Removed RESET pin function.
15. Removed WAKE pin function.
16. Removed ALERT pin configuration.
17. Register set changes are shown in Table A-1, "Register Delta".
TABLE A-1: REGISTER DELTA
Address Register Delta Delta Default
00h
Page 26 Added bits - Main
Control Register Added C_GAIN[1:0] and COMBO bits.
Changed function of GAIN[1:0] bits if
COMBO bit is set. 00h
02h
Page 28 Added bits - General
Status Register
Added bit 4 PWR for new Power Button
feature. Added bit 5 ACAL_FAIL to
indicate analog calibration fa ilure. Added
bit 6 BC_OUT. Removed bit 4 LED
status.
00h
04h Removed - LED Status
Register removed register n/a
20h
Page 32 Removed bit -
Configuration Register Removed bit 6 WAKE_CFG. 20h
26h
Page 38
Renamed Calibration
Activate and Status
Register and added
functionality
In addition to forcing a calibration, the
register also indicates the status of
calibration for each sensor input. 00h
29h
Page 40 New - Signal Guard
Enable Register new register for Signal Guard feature 00h
CAP1298
DS00001571B-page 62 2013-2015 Microchip Technology Inc.
2Eh
Page 43 New - Base Count Out
of Limit Register new register for calibration status 00h
44h
Page 32 Added and removed
bits - Configuration 2
Register
Added bit 1 ACAL_FAIL_INT. Changed
bit 4 from BLK_POL_MIR to
BC_OUT_INT. Changed bit 6 from
ALT_POL to BC_OUT_RECAL.
Removed bit 7 INV_LINK_TRAN.
40h
60h
Page 50 New - Power Button
Register new register for Power Button feature 00h
61h
Page 50 New - Power Button
Configuration Register new register for configuring the Power
Button feature 00h
71h Removed - LED Output
Type Register removed register n/a
72h Removed - Sensor
Input LED Linking
Register removed register n/a
73h Removed - LED
Polarity Register removed register n/a
74h Removed - LED Output
Control Register removed register n/a
77h Removed - Linked LED
Transition Control
Register removed register n/a
79h Removed - LED Mirror
Control Register removed register n/a
80h
Page 52 Added - Calibration
Sensitivity Config 1 new register for proximity 00h
81h
Page 52 Changed - Calibration
Sensitivity Config 2 Changed from LED Behavior register to
new register for proximity 00h
82h Removed - LED
Behavior Register 2 removed register n/a
84h Removed - LED Pulse
1 Period removed register n/a
85h Removed - LED Pulse
2 Period removed register n/a
86h Removed - LED
Breathe Period
Register removed register n/a
88h Removed - LED Config
Register removed register n/a
90h Removed - LED Pulse
1 Duty Cycle Register removed register n/a
91h Removed - LED Pulse
2 Duty Cycle Register removed register n/a
TA BLE A-1: REGISTER DELTA (CONTINUED)
Address Register Delta Delta Default
2013-2015 Microchip Technology Inc. DS00001571B-page 63
CAP1298
92h Removed - LED
Breathe Duty Cycle
Register removed register n/a
93h Removed - LED Direct
Duty Cycle Register removed register n/a
94h Removed - LED Direct
Ramp Rates Register removed register n/a
95h Removed - LED Off
Delay removed register n/a
FDh
Page 52 Changed - Product ID New product ID for CAP1298 71h
FFh
Page 53 Changed - Revision
Register Revision changed. 00h
TA BLE A-1: REGISTER DELTA (CONTINUED)
Address Register Delta Delta Default
CAP1298
DS00001571B-page 64 2013-2015 Microchip Technology Inc.
7.0 REVISION HISTORY
TABLE 7-1: REVISION HISTORY
Revision Level and Date Section/Figure/Entry Correction
DS00001571B (08-25-15) Added 14-lead SOIC packages, SOIC pinout
diagrams, package marking.
Updated ordering information.
CAP1298 Revision A replaces the previous SMSC version Revision 1.0
2013-2015 Microchip Technology Inc. DS00001571B-page 65
CAP1298
THE MICROCHIP WEB SITE
Microchip provides online support via our WWW site at www.microchip.com. This web site is used as a me ans to make
files and information easily available to customers. Accessible by using your favorite Internet browser , the web site con-
tains the following information:
•Product Support – Data sheets and errata, application notes and sample programs, design resources, user’s
guides and hardware support documents, latest software releases and archived software
•General Technical Support – Frequently Asked Questions (FAQ), technical support requests, online discussion
groups, Microchip consultant program member listing
•Business of Mic r oc hi p – Product selector and ordering guides, latest Microchip press releases, listing of semi-
nars and events, listings of Microchip sales offices, distributors and factory representatives
CUSTOMER CHANGE NOTIFICATION SERVICE
Microchip’s customer notification service helps keep customers current on Microchip products. Subscribers will receive
e-mail notification whenever there are changes, updates, revisions or errata related to a specified product family or
development tool of interest.
To register, access the Microc hip web site at www.microchip.com. Under “Supp ort”, cli ck on “Customer Ch ange Notifi-
cation” and follow the registration instructions.
CUSTOMER SUPPORT
Users of Microchip products can receive assistance through several channels:
• Distributor or Representative
• Local Sales Office
• Field Application Engineer (FAE)
• Technical Support
Customers should contact their distributor, representative or field application engineer (FAE) for support. Local sales
offices are also available to help customers. A listing of sales offices and locations is i ncluded in the back of this docu-
ment.
Technical support is available through the web site at: http://www.microchip.com/support
CAP1298
DS00001571B-page 66 2013-2015 Microchip Technology Inc.
PRODUCT IDENTIFICATION SYSTEM
To order or obtain information, e.g., on pricing or delivery, refer to the factory or the listed sales office.
Device: CAP1298
Tape and Reel
Option TR Tape and Reel
Package:(2) A4 16-pin QFN
SL 14-pin SOIC
Examples:
a) CAP1298-1-A4-TR
0b0101_000[r/w] Ad dress
16-pin QFN package
b) CAP1298-2-SL-TR
0b0101_001[r/w] Ad dress
14-pin SOIC package
Note 1: Tape and Reel identifier only appears in the
catalog part number description. This iden-
tifier is used for ordering purposes and is
not printed on the device package. Chec k
with your Microchip Sales Office for pack-
age availability with the Tape and Reel
option.
2: For other small form-factor package avail-
ability and marking information, please
visit www.microchip.com/packaging or
contact your local sales office.
PART NO. [X] XX
Package Address
Option
Device
[XX]
Tape and Reel
Option
-
-
2013-2015 Microchip Technology Inc. DS00001571B-page 67
CAP1298
Information contained in this publication regarding device applications and the like is provided only for your convenience and may be
superseded by updates. It is your responsibility to ensure that your application meets with your specifications. MICROCHIP MAKES NO
REPRESENTATIONS OR WARRANTIES OF ANY KIND WHETHER EXPRESS OR IMPLIED, WRITTEN OR ORAL, STATUTORY OR
OTHERWISE, RELA TED TO THE INFORMA TION, INCLUDING BUT NOT LIMITED TO ITS CONDITION, QUALITY, PERFORMANCE,
MERCHANT ABILITY OR FITNESS FOR PURPOSE. Microchip disclaims all liability arising from this information and its use. Use of Micro-
chip devices in life support and/or safety applications is entirely at the buyer ’s risk, and the buyer agrees to defend, indemnify and hold
harmless Microchip from any and all damages, claims, suits, or expe nses resulting from such use. No licenses are conveyed, implic itly or
otherwise, under any Microchip intellectual propert y righ t s unless ot herwise stated.
Trademarks
The Microchip name and logo, the Microchip logo, dsPIC, FlashFlex, flexPWR, JukeBlox, KEELOQ, KEELOQ logo, Kleer, LANCheck,
MediaLB, MOST, MOST logo, MPLAB, OptoLyzer , PIC, PICST AR T, PIC32 logo, RightTouch, S pyNIC, SST, SST Logo, SuperFlash and
UNI/O are registered trademarks of Microchip Technology Incorporated in the U.S.A. and other countries.
The Embedded Control Solutions Company and mTouch are registered trademarks of Microchip Technology Incorporated in the U.S.A.
Analog-for-the-Digital Age, BodyCom, chipKIT, chipKIT logo, CodeGuard, dsPICDEM, dsPICDEM.net, ECAN, In-Circuit Serial
Programming, ICSP, Inter-Chip Connectivity, KleerNet, KleerNet logo, MiWi, MPASM, MPF, MPLAB Certified logo, MPLIB, MPLINK,
MultiTRAK, NetDetach, Omniscient Code Generation, PICDEM, PICDEM.net, PICkit, PICtail, RightTouch logo, REAL ICE, SQI, Serial
Quad I/O, Total Endurance, TSHARC, USBCheck, VariSense, ViewSpan, WiperLock, Wireless DNA, and ZENA are trademarks of
Microchip Technology Incorporated in the U.S.A. and other countries.
SQTP is a service mark of Microchip Technology Incorporated in the U.S.A.
Silicon Storage Technology is a registered trademark of Microchip Technology Inc. in other countries.
GestIC is a registered trademark of Microchip Technology Germany II GmbH & Co. KG, a subsidiary of Microchip Technology Inc., in
other countries.
All other trademarks mentioned herein are property of their respective companies.
© 2013-2015, Microchip Technology Incorporated, Printed in the U.S.A., All Rights Reserved.
ISBN: 9781632776792
Note the following details of the code protection feature on Microchip devices:
• Microchip products meet the specification contained in their particular Microchip Data Sheet.
• Microchip believes that its family of products is one of the most secure families of its kind on the market today, when used in the
intended manner and under normal conditions.
• There are dishonest and possibly illegal methods used to breach the code protection feature. All of these methods, to our
knowledge, require using the Microchip products in a manner outside the operating specifications contained in Microchip’s Dat a
Sheets. Most likely, the person doing so is engaged in theft of intellectual property.
• Microchip is willing to work with the customer who is concerned about the integrity of their code.
• Neither Microchip nor any other semiconductor manufacturer can guarantee the security of their code. Code protection does not
mean that we are guaranteeing the product as “unbreakable.”
Code protection is constantly evolving. We at Microchip are committed to continuously improving the code protection features of our
products. Attempts to break Microchip’ s code protection feature may be a violation of the Digit al Millennium Copyright Act. If such acts
allow unauthorized access to your software or other copyrighted work, you may have a right to sue for relief under that Act.
Microchip received ISO/TS-16949:200 9 certif ication for its worldwide
headquarters, design and wafer fabrication facilities in Chandler and
Tempe, Arizona; Gresham, Oregon and design centers in California
and India. The Company’s quality system processes and procedures
are for its PIC® MCUs and dsPIC® DSCs, KEELOQ® code hopping
devices, Serial EEPROMs, microperi pherals, nonvola tile memo ry and
analog product s. In addition, Microchip ’s quality system for the design
and manufacture of development systems is ISO 9001:2000 certified.
QUALITYMANAGEMENTS
YSTEM
CERTIFIEDBYDNV
== ISO/TS16949==
2013-2015 Microchip Technology Inc. DS00001571B-page 68
AMERICAS
Corporate Office
2355 West Chandler Blvd.
Chandler, AZ 85224-6199
Tel: 480-792-7200
Fax: 480-792-7277
Technical Support:
http://www.microchip.com/
support
Web Address:
www.microchip.com
Atlanta
Duluth, GA
Tel: 678-957-9614
Fax: 678-957-1455
Austin, TX
Tel: 512-257-3370
Boston
Westborough, MA
Tel: 774-760-0087
Fax: 774-760-0088
Chicago
Itasca, IL
Tel: 630-285-0071
Fax: 630-285-0075
Cleveland
Independence, OH
Tel: 216-447-0464
Fax: 216-447-0643
Dallas
Addison, TX
Tel: 972-818-7423
Fax: 972-818-2924
Detroit
Novi, MI
Tel: 248-848-4000
Houston, TX
Tel: 281-894-5983
Indianapolis
Noblesville, IN
Tel: 317-773-8323
Fax: 317-773-5453
Los Angeles
Mission Viejo, CA
Tel: 949-462-9523
Fax: 949-462-9608
New York, NY
Tel: 631-435-6000
San Jose, CA
Tel: 408-735-9110
Canada - Toronto
Tel: 905-673-0699
Fax: 905-673-6509
ASIA/PACIFIC
Asia Pacific Office
Suites 3707-14, 37th Floor
Tower 6, The Gateway
Harbour City, Kowloon
Hong Kong
Tel: 852-2943-5100
Fax: 852-2401-3431
Australia - Sydney
Tel: 61-2-9868-6733
Fax: 61-2-9868-6755
China - Beijing
Tel: 86-10-8569-7000
Fax: 86-10-8528-2104
China - Chengdu
Tel: 86-28-8665-5511
Fax: 86-28-8665-7889
China - Chongqing
Tel: 86-23-8980-9588
Fax: 86-23-8980-9500
China - Dongguan
Tel: 86-769-8702-9880
China - Hangzhou
Tel: 86-571-8792-8115
Fax: 86-571-8792-8116
China - Hong Kong SAR
Tel: 852-2943-5100
Fax: 852-2401-3431
China - Nanjing
Tel: 86-25-8473-2460
Fax: 86-25-8473-2470
China - Qingdao
Tel: 86-532-8502-7355
Fax: 86-532-8502-7205
China - Shanghai
Tel: 86-21-5407-5533
Fax: 86-21-5407-5066
China - Shenyang
Tel: 86-24-2334-2829
Fax: 86-24-2334-2393
China - Shenzhen
Tel: 86-755-8864-2200
Fax: 86-755-8203-1760
China - Wuhan
Tel: 86-27-5980-5300
Fax: 86-27-5980-5118
China - Xian
Tel: 86-29-8833-7252
Fax: 86-29-8833-7256
ASIA/PACIFIC
China - Xiamen
Tel: 86-592-2388138
Fax: 86-592-2388130
China - Zhuhai
Tel: 86-756-3210040
Fax: 86-756-3210049
India - Bangalore
Tel: 91-80-3090-4444
Fax: 91-80-3090-4123
India - New Delhi
Tel: 91-11-4160-8631
Fax: 91-11-4160-8632
India - Pune
Tel: 91-20-3019-1500
Japan - Osaka
Tel: 81-6-6152-7160
Fax: 81-6-6152-9310
Japan - Tokyo
Tel: 81-3-6880- 3770
Fax: 81-3-6880-3771
Korea - Daegu
Tel: 82-53-744-4301
Fax: 82-53-744-4302
Korea - Seoul
Tel: 82-2-554-7200
Fax: 82-2-558-5932 or
82-2-558-5934
Malaysia - Kuala Lumpur
Tel: 60-3-6201-9857
Fax: 60-3-6201-9859
Malaysia - Penang
Tel: 60-4-227-8870
Fax: 60-4-227-4068
Philippines - Manila
Tel: 63-2-634-9065
Fax: 63-2-634-9069
Singapore
Tel: 65-6334-8870
Fax: 65-6334-8850
Taiwan - Hsin Chu
Tel: 886-3-5778-366
Fax: 886-3-5770-955
Taiwan - Kaohsiung
Tel: 886-7-213-7828
Taiwan - Taipei
Tel: 886-2-2508-8600
Fax: 886-2-2508-0102
Thailand - Bangkok
Tel: 66-2-694-1351
Fax: 66-2-694-1350
EUROPE
Austria - Wels
Tel: 43-7242-2244-39
Fax: 43-7242-2244-393
Denmark - Copenhagen
Tel: 45-4450-2828
Fax: 45-4485-2829
France - Paris
Tel: 33-1-69-53-63-20
Fax: 33-1-69-30-90-79
Germany - Dusseldorf
Tel: 49-2129-3766400
Germany - Karlsruhe
Tel: 49-721-625370
Germany - Munich
Tel: 49-89-627-144-0
Fax: 49-89-627-144-44
Italy - Milan
Tel: 39-0331-742611
Fax: 39-0331-466781
Italy - Venice
Tel: 39-049-7625286
Netherlands - Drunen
Tel: 31-416-690399
Fax: 31-416-690340
Poland - Warsaw
Tel: 48-22-3325737
Spain - Madrid
Tel: 34-91-708-08-90
Fax: 34-91-708-08-91
Sweden - Stockholm
Tel: 46-8-5090-4654
UK - Wokingham
Tel: 44-118-921-5800
Fax: 44-118-921-5820
Worldwide Sales and Service
07/14/15
Mouser Electronics
Authorized Distributor
Click to View Pricing, Inventory, Delivery & Lifecycle Information:
Microchip:
CAP1298-1-A4-TR DM160223