MCS7780
USB 1.1 to IrDA Port
MosChip Semiconductor ♦ 3335 Kifer Rd, Santa Clara, CA 95051 ♦ Tel (408) 737-7141 ♦ Fax (408) 737-7708
General Description
The MCS7780 controller provides bridging between
the Universal Serial Bus (USB) input and an IrDA
wireless data communication port. This device
contains all the necessary logic to communicate
with the host computer via the USB Bus.
The MCS7780 operates in Bus-Powered mode,
and uses a reduced frequency (12MHz) crystal
oscillator. This combination of features allows
signicant cost savings in system design along
with straight forward implementation of IrDA port
functionality into PC peripherals using the host’s
USB port.
Ordering Information
Commercial Grade (0° C to +70° C)
MCS7780CS 28-SSOP Standard
MCS7780CS-GR 28-SSOP RoHS
Features
• USB Specication 1.1 Compliant.
• Supports all USB Standard Commands.
• Full Compliance to IrDA 1.4
• WHQL Certied
• Low-Power CMOS Design
• Powered from USB port
• Single 12 MHz Crystal
• IrDA Data Rates from 2.4 Kbps to 115.2
Kbps in SIR mode
• Supports MIR (Medium IR) at 1.152 Mbps
• Supports FIR (Fast IR) mode with Data
Rate of 4 Mbps
• Uses Standard IrDA Transceivers
• LED Driver capable of 650 mA @ 5V, 25%
Duty Cycle
• Low-Prole 28-Pin SSOP Package
Applications
• High-Speed IrDA Communications
• Cell Phone Interface Cable
Application Note
• AN-7780
Evaluation Board
• MCS7780-EVB
“IrReady Qualied”
in Demo Adapters
Customer boards require
IrDA qualication
MCS7780
USB 1.1 to IrDA Port
Page 2 Rev. 1.2
Block Diagram
PLL & Clock
Generator
USB
Interface
Serial
Interface
Engine
Descriptor
Table
IrDa
Digital Interface
FIFO
FIFO
DP
DM
XTAL1
XTAL2
TX, TX Diode
SD/MODE
RX Fast
RX Slow
MCS7780
USB 1.1 to IrDA Port
Page 3
Rev. 1.2
28-Pin SSOP Package
1
2
3
4
5
6
7
8
9
10
11
12
13
14
28
27
26
25
24
23
22
21
20
19
18
17
16
15
N.C.
N.C.
XTAL2
XTAL1
DGND
nRESET
N.C.
N.C.
N.C.
N.C.
3.3VA
DP
N.C.
N.C.
TXDIODEG
TXDIODE
N.C.
N.C.
RXFAST
TX
RXSLOW
SD/MODE
DGND
3.3V
AGND
DM
N.C.
N.C.
MCS7780CS
MCS7780
USB 1.1 to IrDA Port
Page 4 Rev. 1.2
Pin Descriptions
Pin Name Pin Type Description
TXDIODEG 1 PWR Optional LED Driver Output GND
TXDIODE 2 O Optional Transmit LED Driver Output
RXFAST 5 I Receive Data from IR module (Fast)
TX 6 O Transmit Data output to IR module
RXSLOW 7 I Receive Data from IR module (Slow)
SD/MODE 8 O Mode Control to IR module
DM 12 I/O USB Interface differential Data Negative
DP 17 I/O USB Interface differential Data Positive
nRESET 23 I Master Reset, (active low)
XTAL1 25 I 12 MHz Crystal/Clock Input
XTAL2 26 O 12 MHz Crystal/Clock Output
3.3VA 18 PWR USB Transceiver Power Supply
3.3V 10 PWR Digital Power Supply
AGND 11 PWR USB Transceiver Power Supply Ground
DGND 9, 24 PWR Digital Power Supply Ground
MCS7780
USB 1.1 to IrDA Port
Page 5
Rev. 1.2
Functional Description
The MCS7780 consists of two major functional blocks,
the USB controller, and the digital IR transceiver. The
USB controller provides Control, Bulk-In, and Bulk-Out
endpoints to the USB host. The digital IR transceiver
consists of transmit and receive interfaces that connect
to an analog IR front end.
This USB/lrDA Bridge Controller has full interface
capability to connect between a USB Bus, and an IrDA
compatible infrared transceiver device.
USB Interface
The USB Device Controller implements a USB protocol
engine. It has one conguration with a single interface.
Two Bulk endpoints with maximum packet size of 64
Bytes are used for data transfers. The MCS7780 uses
Vendor Specic commands for IR conguration and
control. Two vendor specic requests (“Write Word”
& “Read Word”) are dened for this purpose. The
vendor specic requests are piped through the Control
endpoint.
“Write Word” is a 2 phase transaction which can be
used to write a single 16-bit register. The setup phase
of this command supplies both the index and data
value to be written into the register. There is no data
phase in this transfer.
The “Read Word” request is used to read the register
contents of the MCS7780. It allows reading one 16-
bit register at a time. The setup phase species the
register address to be read and the data is returned in
the data phase.
Digital IR Transceiver
The Digital IR Transceiver is responsible for driving
the transmit diode and receiving the digital input from
an analog IR front end. The primary components are
the transmit modulator, the receive demodulator, the
FIFO, the analog transmit section, and the register
array.
By programming the registers in the register array, the
device’s operation is determined. Various registers
are used to specify operations such as the modulation
scheme, the Baud rate, the current frame size in the
FIFO, the RX input selection, etc.
In steady state transmit operation, the USB controller
is lling the FIFO with data while the Digital IR
Transceiver is emptying it via the transmit modulator.
In steady state receive operation, the USB controller is
emptying the FIFO while the RX demodulator is lling
the FIFO.
IR FRAMING
Framing involves adding wrappers around the
payload received from NDIS to make a valid IR frame.
MCS7780 uses a custom framing style to achieve low
gate count. The hardware and software together play
a role in making of SIR, MIR, and FIR frames.
MCS7780
USB 1.1 to IrDA Port
Page 6 Rev. 1.2
Mode Register: offset 0x00
Name Bit Access Default Description
FIR 0 * R/W 0 1 = Puts the device in Fast Infrared mode (4MHz).
0 = Device uses SIR/MIR mode based on Baud Rate register.
SIR 1 * R/W 01 = The SIR pulse width of 1.6 uS is used.
0 = The SIR pulse used is 3/16th of bit time.
BBTG 2 R/W 1 1 = Enables back to back transmission with no inter packet gap.
Invalid in SIR mode.
ASK 3 * Reserved Reserved
PARITY 4 * R/W 0 1 = Odd parity to be used by ASK.
0 = Even parity is used
RATE [7:5] * R/W 1 Baud Rate selector. (See Table Below)
PLLPWD 8 R/W 1 1 = Enable power down feature of the PLL
0 = power down feature of the PLL disabled.
DRIVER 9 R/W 0
1 = Upon initialization.
0 = Upon reset.
The Device Driver sets this bit as the rst step of initialization to
enable further access to the register set.
DTD 10 R/W 1
1 = Device determines the transfer direction automatically.
0 = The direction is controlled by software by writing a 1 (TX) or 0
(RX) in DIR bit of this register
DIR 11 R/W 0
1 = Transmit
0 = Receive
This bit is valid only when DTD = 0.
Software should check the CHGDIR bit before writing to this bit.
SIPEN 12 R/W 1
1 = Enables automatic hardware generation of SIP pulse.
0 = Disables the auto SIP generation.
Software must generate it through Vendor Specic commands.
SENDSIP 13 R/W 0 On detecting a transition from low to high on this bit,
the device generates a SIP.
CHGDIR 14 R 1
1 = Software is allowed to change the transfer direction by writing
to DIR bit.
0 = Direction change is not allowed.
Software polls until this bit goes high before changing direction.
RESET 15 R/W 1 0 = Resets the bridge and IR TOP modules.
This bit is self clearing.
* IR needs to be reset when this bit is changed.
Baud Rate Frequency Selected
0 2.4 Kbps
1 9.6 Kbps
2 19.2 Kbps
3 38.4 Kbps
4 57.6 Kbps
5 115.2 Kbps
6 0.576 Mbps
7 1.152 Mbps
MCS7780
USB 1.1 to IrDA Port
Page 7
Rev. 1.2
Framing Register: offset 0x01
Name Bit Access Default Description
STAL [7:0] R/W 0x00
The number of STAs to be used
* Bit-7 = 1, The 6 LSBs indicate the number of STAs to be used.
* Bit-7 = 0, Uses the values hard coded in the design.
IPG [15:8] R/W 0x00
Inter-packet gap
Specied in terms of number of bit times (MIR) or chip time (FIR).
* Bit-15 = 1, The 6 LSBs indicate the inter-packet gap to be used.
* Bit-15 = 0, Uses the values hard coded in the design.
* IR needs to be reset when this bit is changed.
MCS7780
USB 1.1 to IrDA Port
Page 8 Rev. 1.2
XCVR Register: offset 0x02
Name Bit Access Default Description
MODE0 0 R/W 0
Used to congure the transceiver.
The usage varies with the transceiver make and is reected in
the transceiver truth table.
STFIR 1 R/W 0
Used to congure the transceiver.
The usage varies with the transceiver make and is reected in
the transceiver truth table.
XCVR 2 R/W 0 1 = Puts the transceiver in Conguration Mode.
0 = Puts the transceiver in Data Transfer Mode.
RXFAST 3 R/W 0
1 = Causes the device to use RXFAST as the input pin for
receive from transceiver.
0 = Causes the device to use RXSLOW as the receive signal.
TXCUR [6:4] R/W 0 Sets the current control bits of the pad that drives TX-LED.
This controls the current supplied to TX-LED.
MODE1 7 R/W 0
Used to congure the transceiver.
The usage varies with the transceiver make and is reected in
the transceiver truth table.
SMODE0 8 R/W 1 Value of MODE0 to be congured to put it into shut down.
Varies with transceiver make.
SMODE1 9 R/W 0 Value of MODE1 to be congured to put it in shut down.
Varies with transceiver make.
INVTX 10 R/W 0 1 = inverts the data bits being fed into transceiver for transmit.
0 = the transmit line works as active high signal.
INVRX 11 R/W
1 = RXD line from transceiver is treated as an active low signal
0 = RXD line from transceiver is treated as an active high
signal.
EEDATA [15:12] R 0 Loaded from the EEPROM.
MCS7780
USB 1.1 to IrDA Port
Page 9
Rev. 1.2
The table below shows the usage of XCVR Register for various Transceivers.
Vendor Code
Dynamic Conguration
MODE0 MODE1 STC_FIR Latched From
Vishay
TDFU6614 0 1->0 0 0 TXD
Vishay
TDFU6102 0 1->0 0 0 TXD
SHARP
GP2W100YP 1 1->0 0 1 TXD
Agilent
3602/3600 2Can switch pins dynamically.
There is no latching mechanism
SIP Resister: offset 0x03
Name Bit Access Default Description
SIPON [6:0] R/W 0x4C Species pulse width of the SIP
in terms of number of 48 MHz clocks.
SIPOFF [15:7] R/W 0x154 The SIP low time.
Specied as of number of 48 MHz clocks.
MINRXPW Register: offset 0x04
Name Bit Access Default Description
MNRXW [15:0] R/W 0x00
Minimum pulse width of the signal to be received.
0 = Device uses the hard coded values.
X = non zero
Device uses the value specied from this register.
MCS7780
USB 1.1 to IrDA Port
Page 10 Rev. 1.2
TXPW Register: offset 0x05
Name Bit Access Default Description
TXPW [15:0] R/W 0x00
Pulse width of the signal transmitted.
0 = device uses the hard coded values
X = non zero value,
device uses the value specied from this register.
RFIFO2 Register: offset 0x06
Name Bit Access Default Description
TIMEOT [7:0] R/W 0x0A
Timeout specied in intervals of 50mS.
Used in SIR mode to abort a receive if idle for long
period specied by this register.
N => N*50 mS timeout.
TRSHD [14:8] R/W 0x40 FIFO Threshold
CLRFF 15 R/W 0
1 = Clear FIFO pointers
0 = FIFO pointers not cleared
This bit is self clearing
RESV Register: offset 0x07
Name Bit Access Default Description
IRINTX 0 R 0 1 = Indicates that transmit is in progress
0 = Indicates that transmit is not in progress
IRINRX 1 R 0 1 = Indicates that the receive is in progress
0 = Indicates that receive is not in progress
RESV [15:2] R/W 0x0A Reserved
MCS7780
USB 1.1 to IrDA Port
Page 11
Rev. 1.2
Absolute Maximum Ratings
Supply Voltage 3.8 Volts
Voltage at any pin GND - 0.3 to Vcc + 0.3
Operating Temperature -45° C to +90° C
Storage Temperature -65° C to +150° C
Package Dissipation 500 mW
ESD ±2000 Volts
Latch up 220 mA
DC Electrical Specications
Temp = 0° C to +70° C, Vcc = 3.3V ± 10% unless otherwise specied.
Symbol Parameter Min Max Unit Condition
Vcc Supply Voltage 3.0 3.6 V
VclkLClock input low level -0.5 0.6 V External
VclkHClock input high level 2.4 Vcc V External
ViLInput low level 1.08 V CMOS
ViHInput high level 2.1 V CMOS
VoLOutput low level 0.4 V IoL = 4 mA
VoHOutput high level 1.85 V IoH = 4 mA
IiLInput leakage current -10 +10 µA
Icc Operating current 12 19 mA
Cp Input pin Capacitance 5 pF
AC Electrical Specications
Temp = 0° C to +70° C, Vcc = 3.3V ± 10% unless otherwise specied.
Symbol Parameter Min Max Unit Condition
CLKA USB clock frequency 12 12 MHz ±50PPM
MCS7780
USB 1.1 to IrDA Port
Page 12 Rev. 1.2
A2
A1
L
c
E1
E
D
1
14
28
15
e
0.22 TYP
SYMBOL MILLIMETERS INCHES
MIN TYP MAX MIN TYP MAX
A1 0.05 0.21 0.020 0.08
A2 1.65 1.80 0.650 0.708
C 0.25
e 0.65 0.026
D 10.00 10.4 3.93 4.09
E 7.4 7.8 8.2
E1 5.2 5.4 2.05 2.12
L 0.55 0.75 0.95
28-Pin SSOP
Package Dimensions
MCS7780
USB 1.1 to IrDA Port
Page 13
Rev. 1.2
IMPORTANT NOTICE
MosChip Semiconductor Technology, LTD products are not authorized for use as critical components in life
support devices or systems. Life support devices are applications that may involve potential risks of death,
personal injury or severe property or environmental damages. These critical components are semiconductor
products whose failure to perform can be reasonably expected to cause the failure of the life support systems
or device, or to adversely impact its effectiveness or safety. The use of MosChip Semiconductor Technology
LTD’s products in such devices or systems is done so fully at the customer risk and liability.
As in all designs and applications it is recommended that the customer apply sufcient safeguards and guard
bands in both the design and operating parameters. MosChip Semiconductor Technology LTD assumes no
liability for customer’s applications assistance or for any customer’s product design(s) that use MosChip
Semiconductor Technology, LTD’s products.
MosChip Semiconductor Technology, LTD warrants the performance of its products to the current specications
in effect at the time of sale per MosChip Semiconductor Technology, LTD standard limited warranty. MosChip
Semiconductor Technology, LTD imposes testing and quality control processes that it deems necessary to
support this warranty. The customer should be aware that not all parameters are 100% tested for each device.
Sufcient testing is done to ensure product reliability in accordance with MosChip Semiconductor Technology
LTD’s warranty.
MosChip Semiconductor Technology, LTD believes the information in this document to be accurate and reliable
but assumes no responsibility for any errors or omissions that may have occurred in its generation or printing.
The information contained herein is subject to change without notice and no responsibility is assumed by
MosChip Semiconductor Technology, LTD to update or keep current the information contained in this document,
nor for its use or for infringement of patent or other rights of third parties. MosChip Semiconductor Technology,
LTD does not warrant or represent that any license, either expressed or implied, is granted to the user.
MCS7780
USB 1.1 to IrDA Port
Page 14 Rev. 1.2
Revision History
Revision Changes Date
1.0 Corrections Feb-2004
1.1 Corrected Package Dimensions 9-Dec-2005
1.2 Corrected Internal Register Details 3-Jan-2006