_______________General Description
The MAX194 Evaluation System (MAX194EVC16-DIP)
includes the MAX194 evaluation kit and Maxim’s
68HC16 module. Evaluation software supplied with the
kit demonstrates the use of the MAX194 (or the
MAX195) with Motorola’s high-speed QSPI serial inter-
face. Complete source code is included. The EV sys-
tem requires an IBM PC with a serial port and a 5 1/4"
disk drive.
The stand-alone MAX194 Evaluation Kit (MAX194
EVKIT-DIP) is an assembled and tested PC board that
embodies the standard application circuit. Separate
power, digital, and analog ground planes minimize
noise. Jumpers allow several operating modes. The
board generates its own interface timing signals, or can
be connected to a user-provided serial interface.
____________________________Features
♦Proven PC Board Layout
♦Complete Source Code Provided
♦Shutdown-Mode Evaluation
♦High-Speed Serial Interface
♦Convenient Test Points Provided On-Board
♦Operates from a Single 9V to 15V DC Power
Supply
♦Evaluates Both the 14-Bit MAX194 and the 16-Bit
MAX195
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
________________________________________________________________ Maxim Integrated Products 1
PART TEMP. RANGE BOARD TYPE
MAX194EVC16-DIP 0°C to +70°C Through-Hole
______________Ordering Information
___________________________________________________________________EV System
MAX194EVKIT-DIP 0°C to +70°C Through-Hole
68HC16MODULE 0°C to +70°C Through-Hole
Note: PC board labeled MAX195 for both MAX194 EV kit and MAX195 EV kit.
68HC16 MODULE MAX194/MAX195 EV BOARD
{
{
19-0349; Rev 1; 3/95
For pricing, delivery, and ordering information, please contact Maxim Direct at 1-888-629-4642,
or visit Maxim’s website at www.maxim-ic.com.
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
2 _______________________________________________________________________________________
___MAX194 EV System Quick Start
This section applies only to the use of the MAX194 EV
kit with the 68HC16 module.
1) Copy the files from the distribution disk to your hard
disk. Store the MAX194 EV kit software in its own
directory.
2) Carefully align the 40-pin header of the MAX194 EV
kit with the 40-pin connector of the µC module.
Gently press them together. The two boards should
be flush against each other. Note: The MAX194 EV
kit is not supported by the 80C32 module.
3) Make sure the jumpers are configured in accor-
dance with Table 1.
4) Connect a 9V to 15V DC power source to the µC
module, using a small screwdriver. The terminal
block is located next to the on/off switch, in the
upper right corner of the µC module. Plus and
minus are marked on the board.
5) Connect a cable from the computer’s serial port to
the µC module. If using a 9-pin serial port, use a
straight-through 9-pin female-to-male cable. If the
available serial port uses a 25-pin connector, use a
standard 25-pin to 9-pin adapter.
6) To start up the MAX194 software on the IBM PC, set
the current directory to match the directory where
the Maxim software is stored, and then type the pro-
gram name “MAX194”.
7) The program will ask which serial port is connected
to the µC module. Press the space bar until the cor-
rect port is highlighted, then press ENTER. The
MAX194 program will switch to terminal-emulation
mode.
8) At this point, apply power to the 68HC16 module.
The LED should light, and within 5 seconds the pro-
gram will display a logon banner. Note that the LED
is a status indicator, not a power light. It flashes to
indicate module readiness.
9) To download and run the RAM resident code on the
µC module, press ALT+L (that is, hold down the
ALT key as you strike the L key). The program
prompts for the file name. Press the ENTER key to
download and run the file KIT194.S19 on the
68HC16 module.
The KIT194.S19 RAM resident program offers a menu
of commands listed in Table 2.
To evaluate the MAX195, replace U1 with the MAX195.
Table 1. Jumper Configuration when Used
with 68HC16 Module
Table 2. List of Commands Available in
KIT194.S19
JUMPER STATE FUNCTION
JU1 Closed Ground the SCLK pin
JU3 QSPI Conversion clock comes from QSPI clock
JU4 QSPI Chip-select is driven by QSPI PCS0
JU5 QSPI Conversion start is driven by QSPI PCS0
JU6 Open
Open = Normal Operation.
Closed = Reset; do not close this jumper
when using the µC module, because the
µC drives the reset pin.
JU7 68HC16 module selects bipolar/
unipolar/shutdown modes
AUTO
COMMAND FUNCTION
?List available commands.
RRead the MAX194.
—Perform continuous conversions.
O
Oscilloscope demonstration—observe system
timing relationships by operating the MAX194
at full speed without processing data.
!Reset the MAX194.
BSelect bipolar mode.
USelect unipolar mode.
HSelect hexadecimal output.
DSelect decimal output.
LToggle low-power mode on/off.
TSet power-up delay and sleep time.
SCollect a fixed number of samples.
________EV System Component List
QUANTITY DESCRIPTION
1
MAX194 Evaluation Kit (MAX194EVKIT-DIP)1
68HC16 C Module (68HC16MODULE)
Stand-Alone MAX194
_________________EV Kit Quick Start
This section applies only to the use of the MAX194 EV
kit by itself, without the µC module.
1) Make sure the jumpers are configured in accor-
dance with Table 3.
2) Connect the oscilloscope’s channel A probe to the
EOC test point on header J2, and the channel B
probe to the DOUT test point. Ground the scope
probes to the DGND test point or to the GND power
pad. Trigger on the positive edge of channel A.
Set the time base to 2µs per division, and set the
vertical gain to 2V per division.
3) Apply +12V DC to the terminals labeled +12V and
GROUND. The board draws less than 30mA of
supply current.
4) Momentarily close JU6 to reset the MAX194 EV kit.
Leave JU6 open for normal operation.
5) Apply a 0V to 4V signal source between the termi-
nals labeled INPUT+ and INPUT-. The conversion
codes may be observed on the oscilloscope’s
channel A. See the appropriate data sheet for
timing information.
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
_______________________________________________________________________________________ 3
Stand-Alone EV Kit
____________________Component List
DESIGNATION QTY DESCRIPTION
C1, C2, C4, C5, C19,
C20, C23–C26, C29 11 0.1µF ceramic capacitors
C3 11µF ceramic capacitor
C6, C7 215µF, 20V low-ESR capacitors
Sanyo OS-CON 20SA14
C8–C11, C13–C16, C21 910µF, 25V tantalum capaci-
tors
C12, C18, C27 3100µF, 25V electrolytic
capacitors
C17, C171 20.01µF ceramic capacitors
C22 147µF low-ESR capacitor
Sanyo OS-CON 6SA47M
D1, D2 21N5819 Schottky diodes
J1 12x20 female data connector
J2 110-pin header
JU1, JU6 22-pin headers
JU3, JU7 23-way headers
JU4, JU5 23-pin headers
R1, R2 210Ω, 5% resistors
R3, R8 2680Ω, 5% resistors
R4, R41 222Ω, 5% resistors
R5, R51 247kΩ, 5% resistors
R6, R10, R11, R13, R61 51kΩ, 5% resistors
R7 110kΩ, 5% resistor
R9 110MΩ, 5% resistor
U1 1Maxim MAX194
U2 1Maxim MAX874
U3 179L05 negative linear
regulator
U4 1Optional crystal oscillator
U5, U8 2Maxim MAX400
U6 178L05 positive linear
regulator
U7 1ICL7662 inverter
Table 3. Jumper Configuration for Stand-
Alone MAX194 EV Kit
JUMPER STATE FUNCTION
JU1 Closed Ground the SCLK pin
JU3 OSC Conversion clock comes from crystal
oscillator module
JU4 GND Tie CS to GND, enabling data output on
DOUT
JU5 CONT Tie CONV to EOC, continuous-conver-
sion mode
JU6 Open Open = Normal Operation
Closed = Reset
JU7 UNI Select unipolar mode
Evaluates: MAX194/MAX195
__Detailed Description of Software
EPROM Resident Program
A small bootstrap program is stored in the EPROM locat-
ed on the 68HC16 board. The EPROM resident program
initializes the 68HC16, tests the static RAM, configures
the chip-select logic, establishes serial communications
with the host, and downloads program KIT194 into RAM.
It starts operating on power-up or whenever the RESET
button is pressed. After RESET, it tests the RAM, then
waits to receive a serial character on its serial port before
transmitting its identification banner.
RAM Resident Program
KIT194.S19 is a 68HC16 RAM-resident program that is
transferred from disk to the static RAM on the 68HC16
module. When the KIT194 program is running, it offers
the commands listed in Table 2.
Personal Computer Program
MAX194.EXE, which runs on an IBM-compatible com-
puter, is a terminal program that establishes communi-
cation with the 68HC16 module and allows the user to
download and run the Maxim-provided RAM resident
program. The serial communication baud rate is initiat-
ed at 1200 baud (default setting) to ensure proper
operation with basic systems.
The MAX194.EXE program provides several commands
that are associated with the host computer. These com-
mands are listed in Table 4.
The MAX194.EXE program can store the text of a termi-
nal session in a log file. To begin recording the terminal
session, press ALT+O [the letter O]. The program will
ask for a file name. Press ENTER to accept the default
file name, or type in a different name. If a file with that
name already exists, the old file will be erased. To close
the file, press ALT+C. The log file will contain the com-
plete text of the terminal session from the time the file is
opened until it is closed.
Using the QSPI to Read the MAX194
The 68HC16 module uses its Queued Serial Peripheral
Interface (QSPI) in master mode to read the MAX194.
The MAX194 EV kit software uses the algorithm
described below. Refer to the example program of
Listing 1, which assigns QSPI entries 0 and 1 and pro-
grammable chip-select PCS0 to the MAX194. Note:
This interface scheme requires that the QSPI clock be
active during the MAX194 reset (see Reset and
Calibration Procedure section).
1) Initialize the QSPI parameters as follows:
2) Verify that EOC is low before starting the conversion.
3) Start the QSPI transfer.
4) Wait until QSPI transfer is complete. The CPU may
perform other tasks while waiting.
5) Extract the significant bits from QSPI RAM. Bits
B13–B06 are located in QSPI receive RAM entry
RR0 bits 7–0, and bits B05–B00 are located in entry
RR1 bits 9–4. RR1 bits 3–2 are the sub-LSB bits of
the MAX194 (see Table 5).
MAX194 Evaluation System/Evaluation Kit
4 _______________________________________________________________________________________
Table 4. Commands Available in
MAX194.EXE Terminal Program
KEY COMMAND
ALT+L Load and run resident code on 68HC16.
ALT+X Exit to DOS.
ALT+P Change port (COM1, COM2).
ALT+R Send RESET command to 68HC16.
ALT+O Open a log file.
ALT+C Close the log file.
ALT+B Display baud rate menu.
ALT+1 1200 baud
ALT+4 4800 baud
ALT+9 9600 baud
19200 baudALT+2
PARAMETER VALUE EXPLANATION
SPBR 51.68MHz serial clock
CPOL 0 Serial clock is low when idle
CPHA 1CPOL ≠CPHA, data valid on
falling clock edge
BITS $0A
Ten bits per QSPI transfer. Use
two consecutive QSPI transfers
to read the MAX194.
DSCKL 2
Delay 119ns between CS and first
clock in the first QSPI transfer to
satisfy MAX194 tDA.
COMD.0 $D0
Control RAM for first QSPI trans-
fer: CONT = 1, BITSE = 1, DTL =
0, DSCK = 1, PSC0 = 0
COMD.1 $40
Control RAM for second QSPI
transfer: CONT = 0, BITSE = 1,
DTL = 0, DSCK = 0, PSC0 = 0
NEWQP 0Index of first queue entry to
execute
ENDQP 1Index of last valid queue entry
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
_______________________________________________________________________________________ 5
Listing 1. Sample Code for 68HC16 Interface
Evaluates: MAX194/MAX195
Using Bit-Pushing to Read the MAX194
The MAX194 may be interfaced using a bit-pushing
algorithm, such as the following:
1) Verify that EOC is low before starting the conversion.
2) Assert CONV low to begin conversion.
3) Wait until EOC becomes high. Conversion has
begun.
4) Set CONV high.
5) Wait until EOC becomes low. Conversion is com-
plete.
6) Assert SCLK low.
7) Assert CS low.
8) Clear the 16-bit result register.
9) Repeat 16 times:
9-1. Set SCLK high.
9-2. Rotate the 16-bit result register left.
9-3. Read DOUT into least significant bit of the
result register.
9-4. Assert SCLK low.
10) Set CS high.
Reset and Calibration Procedure
When the MAX194 is installed in an environment with an
unregulated temperature, thermal variation can cause
DC offset errors. Transients on the power supply or ref-
erence during the power-on calibration are also a
source of DC offset error. These errors can be eliminat-
ed by performing re-calibration, as outlined below:
1) Assert the MAX194 RESET pin low.
2) Run the conversion clock until EOC becomes high.
3) Set the MAX194 RESET pin high.
4) Run the conversion clock until EOC becomes low.
For best accuracy, a typical application circuit should
allow time for the power supply and ambient tempera-
ture to settle before re-calibrating the MAX194. Refer to
the Calibration section of the MAX194 data sheet.
_Detailed Description of Hardware
Jumper Options
Several jumper blocks allow different configurations of
the MAX194. Jumper functions are listed in Table 6.
See the Voltage Reference and Measuring Supply
Current sections.
Data Connector Interface
The 68HC16 module and MAX194 communicate
through the QSPI port on the 40-pin data connector.
Table 7 lists the function of each pin.
MAX194 Evaluation System/Evaluation Kit
6 _______________________________________________________________________________________
Table 6. Jumper Settings
JUMPER POSITION FUNCTION
Closed Ground the SCLK pin.
JU1
Open Allows the SCLK pin to be driven by
the user.
“OSC” Conversion clock is driven by crystal
oscillator U4.
“EXT” Conversion clock is driven by the
EXTCLK input pad.
“QSPI” Conversion clock is driven by the
QSPI serial clock.
“QSPI” Connects CS to QSPI chip-select
PCS0.
JU4
“GND” Connects CS to ground; data output
is always enabled.
“QSPI” Connects CONV to QSPI chip-select
PCS0.
JU5
“CONT” Connects CONV to EOC for continu-
ous conversion mode.
Open Normal operating mode.
JU6 Closed
Momentary closure resets and
re-calibrates the MAX194. Do not
close this jumper if the µC module is
connected.
“SHDN” Select shutdown mode.
“AUTO”
Lets 68HC16 drive the BP/UP/SHDN
pin. If no µC is connected, bipolar
input mode is selected.
“UNI” Select unipolar mode.
JU7
Open Select bipolar mode.
JU3
Table 5. QSPI Receive Format for MAX194
ADDR 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RR0 x x x x x x x x B13 B12 B11 B10 B9 B8 B7 B6
RR1 x x x x x x B5 B4 B3 B2 B1 B0 sub sub x x
Analog Input Buffer
The analog input to the MAX194 may be buffered by
U8. A MAX400 is used because of its low VOS drift. The
feedback circuit consists of four passive components:
R41, R61, C171, and R51. R41 isolates the op-amp’s
output from the dynamic capacitive load at the AIN
input. R61 makes the network accurate at the reference
input (without R61, the reference voltage would appear
at the output of the op amp). C171 compensates the
high-frequency response by making R51 dominate at
high frequencies.
Input offset may be improved by adding a 1000pF to
0.01µF ceramic capacitor at site C28.
Voltage Reference
The voltage reference U2 provides a 4.096V reference,
which is buffered by U5. The buffer isolates the refer-
ence from the MAX194’s capacitive switching load. To
eliminate the buffer circuit, cut traces JU8 and JU9 and
connect a wire from JU9 pin 1 to the VREF pad.
Reference Buffer
The reference input to the MAX194 may be buffered by
U5. The MAX400 op amp is used because of its low
VOS drift. By using a bipolar (instead of CMOS) op
amp, the substrate can be connected to the quiet ana-
log ground, reducing the noise coupled through the
power supplies. The feedback circuit consists of four
passive components: R4, R6, C17, and R5. R4 isolates
the op-amp’s output from the heavy capacitive load
that bypasses the VREF pin. R6 makes the network
accurate at the reference input (without R6, the refer-
ence voltage would appear at the output of the op
amp). C17 compensates the high-frequency response
by making R5 dominate at high frequencies.
The reference buffer U5 draws its power through the
lowpass filter formed by R3 and C18. The filter provides
the necessary power-supply rejection. U5 is powered
by the unregulated input supply to ensure enough
headroom to buffer the 4.096V reference.
Layout, Power Supplies, and Grounding
Good PC board layout necessary to achieve specified
performance, and an analog ground plane is essential
for optimum performance. The PC board layout artist
must be provided with explicit instructions, preferably a
pencil sketch of the placement of sensitive analog com-
ponents and the routing of ground connections. See
the EV kit PC board layout for an example. Use the fol-
lowing guidelines:
1) At the schematic level, keep the analog power sup-
plies and grounds separate from all other power
supplies and grounds. Digital power may be con-
nected to analog power through a 10Ωseries resis-
tor to attenuate digital noise.
2) Cluster the MAX194, the voltage reference, and any
input or reference buffers near the site where the
analog signal enters the board. Place 0.1µF ceramic
decoupling capacitors within 10mm of the MAX194’s
power-supply and voltage-reference pins.
3) Keep the analog-input signal ground return sepa-
rate from the analog ground plane, connecting to
analog ground only at the AGND pin of the
MAX194. The analog input and its signal ground-
return traces should both follow the same route to
help reject common-mode noise.
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
_______________________________________________________________________________________ 7
Table 7. Data-Interface Connections
PIN NO. 68HC16 SIGNAL MAX194 SIGNAL FUNCTION
1–4 GND GND Ground
5, 6 +12V +12V Unregulated 12V DC Supply
7, 8 +5V VDDD Regulated +5V DC from 68HC16 Module
9–26 Reserved Reserved Reserved
27 IC1 EOC End-of-Conversion Output from MAX194
28, 29, 30 Reserved Reserved Reserved
31 OC2 RESET Active-Low RESET to MAX194
32 OC3 BP/UP/SHDN Shutdown/Bipolar/Unipolar Input to MAX194
33, 34 Reserved Reserved Reserved
35 MISO DOUT QSPI Master Input; Serial Data Output from MAX194
36 Reserved Reserved Reserved
37 SCK CLK QSPI Serial Clock from 68HC16
38 PCS0 CS QSPI Chip-Select from 68HC16
39, 40 Reserved Reserved Reserved
Evaluates: MAX194/MAX195
The MAX194 evaluation board generates its own high-
quality power supplies from a single DC input (8V to
20V), such as a plug-in wall transformer. When the
MAX194 evaluation board is connected to the 68HC16
µC module, the µC module uses the unregulated input
supply to generate its own separate +5V digital supply.
U6 converts the unfiltered input down to +5V to provide
the VDDA analog supply. Current spikes from the digi-
tal supply VDDD are attenuated by R1. Schottky diode
D1 protects the device substrate. U7 inverts the +12V
to -12V, and U3 regulates the -12V to -5V, providing the
VSSA analog supply.
Measuring Supply Current
To measure the supply current drawn by the MAX194,
turn off the power and prepare the board by carefully
cutting the traces at IS1, IS2, IS3, and IS4, and
installing 2-pin headers and shunts (see Table 8).
Each supply may be measured by replacing the corre-
sponding shunt with a current-meter connection. For
example, to measure the current drawn by the +5V dig-
ital supply, replace the shunt at IS4 with a current
meter. The direction of current flow is marked with
arrows on the silkscreen. Do not connect or disconnect
the current meter while the power is on.
After observing supply current in operating and shut-
down modes, the board may be restored by installing
shunts at IS1–IS4.
MAX194 Evaluation System/Evaluation Kit
8 _______________________________________________________________________________________
JUMPER POWER SUPPLY DESCRIPTION
IS1 VDDA Analog +5V
IS2 VSSA Analog -5V
IS3 VSSD Digital -5V
IS4 VDDD Digital +5V
Table 8. Current-Sense Jumpers
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
_______________________________________________________________________________________ 9
RESET
10
CONV
9
CS
13
2CONVCLK
12
8
DOUT
5
SCLK
3
EOC
7
BP / UP/ SHDN
1
4
5
8
BUFFERED
INPUT
1
D2
1N5819 7
6
2
3
= DIGITAL
GROUND
= ANALOG
GROUND
MAX194
U8
MAX400CPA
DGND VSSD
VSSD
AGND VSSA
VSSA
VDDD VDDA
VDDA
AIN
AIN
REF
CLK
-9V / FILTERED
+9V / FILTERED
C9
10µF
C4
0.1µF
C8
10µF
C2
0.1µF
C29
0.1µF
C26
0.1µF
C171
0.01µF
C7
15µF
C6
15µF
C1
0.1µF
C5
0.1µF
R41
22Ω
R61
1k
R51, 47k
R12, 20k
INPUT BUFFER (OPTIONAL)
R9
10M
RESET
CONV
CS
DOUT
SCLK
EOC
BP / UP/ SHDN
VREF 4
12
5
8
1
7
6
2
VIN
TEMP
GND
8
7
6
5
COMP
VOUT
TRIM
1
2
3
DIRECT INPUT
4
416
3
3
U5
MAX400CPA
MAX874
U2
U1
-9V / FILTERED
JU10
+9V / FILTERED
R17
4M (OPTIONAL)
+12V / UNREGULATED
R16
1M (OPTIONAL)
R15
2M (OPTIONAL)
JU9
JU2
JU8
C24
0.1µF
C19
0.1µF
4.096V
C17
0.01µF
C23
0.1µF
C28
(OPTIONAL)
1000pF
to 0.01µF
C30
(OPTIONAL)
15µF
20V
C21
10µF
C20
0.1µF
R4
22Ω
R6
1k
R5, 47k
611 14 15
REFERENCE BUFFER
C3
1µF
C22
47µF
LOW-ESR
SANYO
6SA47M
IS3
VDDD
IS4 IS1
IS2
Figure 1. MAX194 EV Kit Schematic
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
10 ______________________________________________________________________________________
R7, 10k
R10, 1k
R11, 1k
VDDD
VDDD
JU6
"AUTO"
"SHDN"
"UNI"
"OSC" "EXT"
JU7
JU3
R13, 1k
RESET
CONV
CONCLK
R18
270Ω
(OPTIONAL)
R19
270Ω
(OPTIONAL)
DOUT
VDDD
EOC
U4
TEST POINTS
VDDD
XTAL
OSC.
BP / UP/ SHDN
CONVCLK
J3-2 (FSR)
J3-4 (DR)
(CLKR) J3-9
(XF1) J3-8
J3-1
J3-10
J2-1
CONV
CS
DGND
RESET
CONVCLK
VDDD
DOUT
SCLK
EOC
BP / UP/ SHDN
J2-2
J2-3
J2-4
J2-5
J2-6
J2-7
J2-8
J2-9
J2-10
J1-27P1.0 / IC1
24
1
3
2
14
C25
0.1µF
4
11
7
8EXTCLK1
3
1
EOC
"GND"
"QSPI"
"QSPI"
"CONT" "QSPI"
JU4
Chip Select
JU5
CONV Select
CS
CONV
SCLK
1
QSPI_PCSO
QSPI_PCSO
QSPI_PCSO
EOC
2
3
1
2
3
J1-28P1.1 / IC2
J1-29P1.2 / IC3
J1-30P1.3 / OC1
J1-31P1.4 / OC2
J1-32P1.5 / OC3
2x20 HEADER
J1-35MISO DOUT
J1-36MOSI
J1-37SCK
J1-38PCSO / SS
J1-39CLKOUT
J1-40PWMA
J1-33P1.6 / OC4
J1-34P1.7 / IC4
JU1
= DIGITAL
GROUND
= ANALOG
GROUND
Figure 1. MAX194 EV Kit Schematic (continued)
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
______________________________________________________________________________________ 11
R1
10Ω
R3
600Ω
R8
600Ω
D1
1N5819
VDDD
VDDA
78LO5
U6
GND
R2
10Ω
JU11
J1-1GND
C15
10µF
C18
100µF
C27
100µF
C16
10µF
1
IN OUT
3
2
PGND
+12V / UNREG
J1-2GND
J1-3GND
J1-4GND
GND
POS5
2x20 HEADER
J1-5UNREG +12VDC
VSSD
VSSA
AGND
X3
79LO5
U3
GND
ICL7662
U7
C14
10µF
C13
10µF
3
1
IN OUT
2
NEG12 NEG5
J1-6UNREG +12VDC
2x20 HEADER J1-7
J1-8
POS12
-9V / FILTERED
+9V / FILTERED
HC16 +5V
+12V / UNREG
+12V / UNREG
+12V / UNREG
-12V / UNREG
C10
10µF
C12
100µF
C11
10µF
CAP+
CAP-
NC
GND
8
7
6
5
V+
VOUT
OSC
LV
1
2
3
4
= POWER
GROUND
= ANALOG
GROUND
-12V/UNREG
Figure 1. MAX194 EV Kit Schematic (continued)
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
12 ______________________________________________________________________________________
Figure 2. MAX194 EV Kit Component Placement Guide—Component Side
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
______________________________________________________________________________________ 13
Figure 3. MAX194 EV Kit PC Board Layout—Component Side
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
14 ______________________________________________________________________________________
Figure 4. MAX194 EV Kit PC Board Layout—Solder Side
68HC16 Module
________________General Description
The 68HC16 module is an assembled and tested print-
ed-circuit board intended for use with Maxim’s high-
speed serial-interface evaluation kits (EV kits). The
module uses an inexpensive 8-bit implementation of
Motorola’s MC68HC16Z1 microcontroller (µC) to collect
data samples at high speed using the QSPI™ interface.
It requires an IBM-compatible personal computer and
an external DC power supply, typically 12V DC or as
specified in EV kit manual.
Maxim’s 68HC16 module is provided to allow cus-
tomers to evaluate selected Maxim products. It is not
intended to be used as a microprocessor development
platform, and such use is not supported by Maxim.
™ QSPI is a trademark of Motorola Corp.
68HC16 Module
________________Detailed Description
Power Input Connector J2
The 68HC16 module draws its power from a user-sup-
plied power source connected to terminal block J2. Be
sure to note the positive and negative markings on the
board. A three-terminal 5V regulator allows input volt-
ages between 8V and an absolute maximum of 20V.
The 68HC16 module typically requires 200mA of input
current.
68HC16 Microcontroller
U1 is Motorola’s 68HC16Z1 µC. Contact Motorola for
µC information, development, and support. Maxim EV
kits use the high-speed queued serial peripheral inter-
face (QSPI) and the internal chip-select generation.
A MAX707 on the module monitors the 5V logic supply,
generates the power-on reset, and produces a reset
pulse whenever the reset button is pressed.
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
______________________________________________________________________________________ 15
_____________________________________________68HC16 Module Component List
Right-angle printed circuit board
mount, DB9 female socket
1J3
2-circuit terminal block1J2
40-pin right-angle male connector1J1
1N4001 diode1D1
0.1µF capacitors5C10–C14
Reference designator, not used0C9
0.01µF capacitor1C8
22pF capacitors2C6, C7
22µF, 25V radial-lead electrolytic
capacitors
2C4, C5
1µF ceramic capacitors3C1, C2, C3
DESCRIPTIONQTYDESIGNATION
10MΩ, 5% resistor1R1
Light-emitting diode1LED1
Empty0L2
Empty0L1
Empty0JU5
Empty0JU4
Empty0JU3
Reference designator, not used0JU2
Empty0JU1
Empty0J4
Right-angle printed circuit board
mount, DB9 female socket
1J3
2-circuit terminal block1J2
40-pin right-angle male connector1J1
1N4001 diode1D1
0.1µF capacitors5C10–C14
Reference designator, not used0C9
0.01µF capacitor1C8
22pF capacitors2C6, C7
22µF, 25V radial-lead electrolytic
capacitors
2C4, C5
1µF ceramic capacitors3C1, C2, C3
DESCRIPTIONQTYDESIGNATION
10MΩ, 5% resistor1R1
Light-emitting diode1LED1
Empty0L2
Empty0L1
Empty0JU5
Empty0JU4
Empty0JU3
Reference designator, not used0JU2
Empty0JU1
Empty0J4
Evaluates: MAX194/MAX195
The 68HC16 uses a phase-locked loop (PLL) to set its
bus speed. Crystal Y1 is a 32.768kHz frequency refer-
ence. The internal oscillator runs 256 times faster than
the external crystal. When the 68HC16 is reset, it waits
for the PLL to lock before it executes any software. After
the PLL locks onto the reference frequency, the soft-
ware doubles the clock speed by writing to the clock
synthesizer control register, selecting a bus speed of
16.78MHz.
U5, the user RAM area, is a 32kbyte CMOS static RAM.
The 74HCT245 octal buffer lets the 68HC16 module
access an 8-bit port on the 40-pin interface connector.
This memory-mapped port consists of separate read
and write strobes, four chip selects, four address LSBs,
and eight data bits.
Serial Communications
J3 is an RS-232 serial port, designed to be compatible
with the IBM PC 9-pin serial port. Use a straight-through
DB9 male-to-female cable to connect J3 to this port. If
the only available serial port has a 25-pin connector,
you may use a standard 25-pin to 9-pin adapter. Table
9 shows the pinout of J3.
The MAX233 is an RS-232 interface voltage level shifter
with two transmitters and two receivers. It includes a
built-in charge pump with internal capacitors that gen-
erates the output voltages necessary to drive RS-232
lines.
40-Pin Data Connector J1
The 20 x 2 pin header connects the 68HC16 module to
a Maxim EV kit. Table 10 lists the function of each pin.
Note that 68HC16 object code is not compatible with
68HC11 object code. Use the 68HC16 module only
with those modules that are designed to support it, and
only download code that is targeted for the 68HC16
module. Downloading incorrect object code into the
68HC16 module will have unpredictable results.
Address Ranges
The 68HC16 µC generates various enable signals for
different address ranges. The ROM and RAM enable
signals are fed directly to the respective chips. Several
additional signals (J1.11–J1.14) are available on the
data connector to be used by Maxim EV kits. Table 11
outlines the address ranges for each of the elements
found on the 68HC16 module, and Table 12 is a truth
table that describes the logic for each of the 68HC16’s
chip-select outputs. Because the addresses are not
completely decoded, the boot ROM and user RAM
have shadows.
MAX194 Evaluation System/Evaluation Kit
16 ______________________________________________________________________________________
Table 9. Serial Communications Port J3
UnusedNone9
Handshake; hard-wired to RTSCTS8
Handshake; hard-wired to CTSRTS7
Handshake; hard-wired to DCD and DTRDSR6
Signal ground connectionGND5
Handshake; hard-wired to DCD and DSRDTR4
RS-232-compatible data input to
68HC16 module
TXD3
Handshake; hard-wired to DTR and DSRDCD1
FUNCTIONNAMEPIN
RS-232-compatible data output from
68HC16 module
RXD2
Table 10. 40-Pin Data-Connector Signals
General I/O port bit 7IC434
General I/O port bit 0 (LSB)IC127
Buffered data bus bits 1–7EXTD1–720–26
Unregulated input voltageVPREREG5, 6
Buffered data bus 0 (LSB)EXTD019
Read strobe
RD
9
GroundGND1–4
FUNCTIONNAMEPIN
Address bit 2A0217
+5V from on-board regulatorVCC7, 8
Chip select for 7E000–7E7FF
7E000
11
Chip select for 7F000–7F7FF
7F000
13
Write strobe
WR
10
Chip select for 7E800–7EFFF
7E800
12
Address bit 0 (LSB)A0015
Chip select for 7F800–7FFFF
7F800
14
Pulse-width-modulator outputPWMA40
QSPI chip-select outputPCS0/SS38
QSPI serial clockSCK37
QSPI master-out, slave-inMOSI36
QSPI master-in, slave-outMISO35
Address bit 1A0116
Address bit 3A0318
General I/O port bit 1IC228
General I/O port bit 2IC329
General I/O port bit 3OC130
General I/O port bit 4OC231
General I/O port bit 5OC332
General I/O port bit 6OC433
System clock outputCLKOUT39
Boot ROM
The boot ROM, U3, is configured as an 8-bit memory
device. Resistor R4 pulls data bit 0 low during system
reset, forcing the µC to fetch instructions using only the
upper eight data bits. The boot ROM checks the sys-
tem and waits for commands from the host. Refer to the
EV kit manual for specific start-up procedures.
Software
All software is supplied on a disk with the EV kit.
Instructions for operating the software are included in
the EV kit manual. Refer to the EV kit manual for more
information.
_______68HC16 Module Self Check
To test the 68HC16 module’s integrity, connect the
power supply to the power terminals (J2). Do not con-
nect anything to J1 or J3. Slide the power switch SW1
to the “ON” position. The LED will light up, and will flash
within 5 seconds.
If the LED flashes with a 50%-on/50%-off duty cycle,
then it passed its self check. Note that this test does
not exercise the RS-232 port or the EV kit 40-pin inter-
face, but it does confirm that the power supply, micro-
processor, ROM, and RAM passed the self test.
If the LED flashes with a 10%-on/90%-off duty cycle,
then it failed its self check. Most likely, the RAM chip
(U5) is bad.
If the LED remains on and does not flash, then the
problem is either U3 (the EPROM), U1 (the micro-
processor), U4 (the regulator), the MAX707 reset gen-
erator, or the power supply. Use a voltmeter to verify
that the power supplies are good. Check the power-
supply input and the +5V output from the regulator.
Use an oscilloscope to see if the 32.768kHz reference
oscillator is running.
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
______________________________________________________________________________________ 17
Table 11. 68HC16 Module Memory Map
(all address values are in 20-bit hex)
Shadow of boot ROM08000–0FFFF
Shadow of user RAM18000–1FFFF
User RAM (U5, strobed by CS0 and CS2)10000–17FFF
Unused20400–7DFFF
Internal standby RAM; 1kbyte20000–203FF
Not accessed by the 68HC1680000–F7FFF
External chip select (J1 pin 11) (CS7)7E000–7E7FF
External chip select (J1 pin 12) (CS8)7E800–7EFFF
External chip select (J1 pin 13) (CS9)7F000–7F7FF
External chip select (J1 pin 14) (CS10)7F800–7FFFF
UnusedF8000–FF6FF
68HC16’s built-in ADC (not used)FF700–FF73F
UnusedFF740–FF8FF
General-purpose timer module (GPT)
Boot ROM (U3, strobed by CSBOOT)
FF900–FF93F
00000–07FFF
FUNCTION
Unused
PIN
FF940–FF9FF
System integration module (SIM)FFA00–FFA7F
UnusedFFA80–FFAFF
Internal standby RAM (SRAM)
control registers
FFB00–FFB07
UnusedFFB08–FFBFF
Queued serial module (QSM)FFC00–FFDFF
UnusedFFE00–FFFFF
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
18 ______________________________________________________________________________________
Table 12. 68HC16 Chip-Select Outputs Truth Table
H1xxxx read
H7E0xx read
H1xxxx write
H7E8xx read
H7E0xx write
H7F0xx write
H7F8xx write
H7F8xx read
H7F0xx read
H7E8xx write
H
H
L
L
H
0xxxx read
CSBOOT
H
ADDRESS
RANGE
H
H
H
H
H
H
CS0
H
L
H
L
H
H
H
L
L
H
L
H
H
H
H
CS1
H
H
H
H
H
H
H
CS2
H
H
H
H
L
L
L
H
H
L
H
L
H
H
L
CS5
L
L
L
L
L
L
H
CS6
H
L
H
H
L
H
H
H
H
H
H
H
H
H
L
CS7
H
H
H
H
H
L
H
CS8
H
H
H
H
H
L
H
H
L
H
H
CS9
H
H
H
H
H
H
L
L
H
H
H
CS10
19
1
2
3
4
5
6
7
8
9
CS6/IOBUFFER
CS1/RDIO
D08
D09
D10
D11
D12
D13
D14
D15
18
17
16
15
14
13
12
11
EXTD0
EXTD1
EXTD2
EXTD3
EXTD4
EXTD5
EXTD6
EXTD7
C13
0.1µF
R5
470Ω
LED1
GND
PWMB
VCC
VCC
VCC
TSTME
BKPT/DSCLK
BKPT/DSCLK
HALT
BERR
MODCLK
DSACK1
DSACK0
IRQ7
2
3
4
5
6
7
8
9
10
R6
10k
SIP
RESISTOR
1
DS
GND
GND
RESET
VCC
J4-1
J4-3
J4-5
J4-7
J4-9
J4-2
J4-4
J4-6
J4-8
J4-10
BERR
BKPT/DSCLK
FREEZE
IPIPE1/DSI
IPIPE0/DS0
OE
DIR
A1
A2
A3
A4
A5
A6
A7
A8
B1
B2
B3
B4
B5
B6
B7
B8
U6
74HCT245
J1-1
J1-3
J1-5
J1-7
J1-9
J1-11
J1-13
J1-15
J1-17
J1-19
J1-21
J1-23
J1-25
J1-27
J1-29
J1-31
J1-33
J1-35
J1-37
J1-39
J1-2
J1-4
J1-6
J1-8
J1-10
J1-12
J1-14
J1-16
J1-18
J1-20
J1-22
J1-24
J1-26
J1-28
J1-30
J1-32
J1-34
J1-36
J1-38
J1-40
GND
GND
VPREREG
VCC
CS1/RDIO
CS7/7E000
CS9/7F000
A00
A02
EXTD0
EXTD2
EXTD4
EXTD6
IC1
IC3
OC2
OC4
MISO
SCK
CLKOUT
GND
GND
VPREREG
VCC
CS5/WRIO
CS8/7E800
CS10/7F800
A01
A03
EXTD1
EXTD3
EXTD5
EXTD7
IC2
OC1
OC3
IC4
MOSI
PCSO/SS
PWMA
GROUND
UNREGULATED 7V TO 20V
REGULATED +5V
INTEL COMPATIBLE READ/WRITE STROBES
CHIP SELECTS
LOW ADDRESS BITS
8-BIT BUFFERED BIDIRECTIONAL DATA BUS
8-BIT GENERAL I/O PORT
HIGH-SPEED SERIAL INTERFACE (QSM/QSPI)
Figure 5. 68HC16 Module Schematic
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
______________________________________________________________________________________ 19
BR
FC2
FC1
VDDE
VSSE
FCO
CSBOOT
DATA0
DATA1
DATA2
DATA3
VSSI
DATA4
DATA5
DATA6
DATA7
DATA8
DATA9
VDDE
VSSE
DATA10
DATA11
DATA12
DATA13
DATA14
DATA15
ADDRO
DSACK0
DSACK1
AVEC
DS
AS
VDDE
A01
A02
VCC
VSSE
A03
A04
A05
A06
A07
A08
VSSI
A09
A10
A11
A12
A13
A14
VCC
VSSE
116
115
114
113
112
111
110
109
108
107
106
105
104
103
102
101
100
99
98
97
96
95
94
93
92
91
90
89
88
87
86
85
84
VRL
ADA6
ADA7
VSTBY
XTAL
VDDSYN
EXTAL
VSSI
VDDI
XFC
VDDE
VSSE
CLKOUT
FREEZE/QUOT
TSTME/TSC
BKPT/DSCLK
IPIPE0/DS0
IPIPE1/DS1
RESET
HALT
BERR
IRQ7
IRQ6
IRQ5
IRQ4
IRQ3
IRQ2
IRQ1
MODCLK
R/W
SIZ1
SIZ0
VSSE
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
TXD
ADDR1
ADDR2
VDDE
VSSE
ADDR3
ADDR4
ADDR5
ADDR6
ADDR7
ADDR8
VSSI
ADDR9
ADDR10
ADDR11
ADDR12
ADDR13
ADDR14
ADDR15
ADDR16
ADDR17
ADDR18
VDDE
VSSE
VDDA
VSSA
ADA0
ADA1
ADA2
ADA3
ADA4
ADA5
VRH
RXD
PCS3
PCS2
PCS1
PCS0/SS
SCK
MOSI
MISO
VSSE
VDDE
IC1
IC2
IC3
OC1
OC2
VSSI
VDDI
OC3
OC4
IC4/OC5
PAI
PWMA
PWMB
PCLK
VSSE
VDDE
ADDR23
ADDR22
ADDR21
ADDR20
ADDR19
BGACK
BG
17
16
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
132
131
130
129
128
127
126
125
124
123
122
121
120
119
118
117
CSO/WRRAM
CS5/WRIO
VCC
VSSE
CSBOOT/RDROM
DOO
VSSI
DO8
DO9
VCC
VSSE
D10
D11
D12
D13
D14
D15
AOO
DSACKO
DSACK1
DS
VCC
RXD
TXD
VCC
CS10/7F800
CS9/7F000
CS8/7E800
CS7/7E000
CS6/IOBUFFER
CS2/RDRAM
CS1/RDIO
VSSE
VCC
IC1
IC2
IC3
OC1
OC2
VSSI
VDDI
OC3
OC4
IC4
PWMA
PWMB
VSSE
MISO
MOSI
SCK
PCSO/SS
XTAL
EXTAL
VSSI
VDDI
VCC
VSSE
CLKOUT
FREEZE
TSTME
BKPT/DSCLK
IPIPEO/DS0
IPIPE1/DSI
RESET
HALT
BERR
IRQ7
MODCLK
VSSE
VCC
VSSE VSTBY
L2
10µH
OPTIONAL
C3
1µF
20V
VSSI
C10
0.1µF
C14
0.1µF
C8
0.01µF
U1
MOTOROLA
MC68HC16Z1CFC16
JU4
Figure 5. 68HC16 Module Schematic (continued)
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
20 ______________________________________________________________________________________
GND
IN OUT
U4
78M05
13
2
+
–
C5
22µF
20V
C4
22µF
25V
VCC
VPREREG
D1
1N4001
SW1
POWER
J2
C7
22pF
C6
22pF
R2
330k
R1
10M
Y1
32.768kHz
XTAL
EXTAL
PFO
N.C.
RESET
RESET
MR
PFI
GND
VCC
VCC
U7
MAX707
1
4
5
6
8
7
3
2
RESET
SW2
RESET
T1OUT
T2OUT
R1IN
R2IN
T1IN
T2IN
R1OUT
R2OUT
J3-8
J3-7
J3-2
J3-3
J3-4
J3-6
J3-1
J3-5
J3-9
CTS
RTS
RXD
TXD
DTR
DSR
DCD
GND
RI
VCC
VCC
7
2
1
3
20
5
18
4
19
C2+
C2+
C2-
C2-
C1+
C1-
V-
V-
V+ GND
GND
GND
8
13
12
17
14
11
15
10
16
U2
MAX233
TXD
GND
RXD
96
C1
1µF
20V
C2
1µF
20V
L1
10µH
OPTIONAL VDDI
VSSI
VCC
VSSE
JU3
JU5
GND VSSE
A00
A01
A02
A03
A04
A05
A06
A07
A08
A09
A10
A11
A12
A13
A14
GND
CS2/RDRAM
CS0/WRRAM
10
9
8
7
6
5
4
3
25
24
21
23
2
26
1
20
22
27
11
12
13
15
16
17
18
19
D08
D09
D10
D11
D12
D13
D14
D15
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
CS
OE
WE
I/O0
I/O1
I/O2
I/O3
I/O4
I/O5
I/O6
I/O7
A(00:18)
D(00:15)
U5
62256
32k x 8-BIT HIGH-SPEED CMOS STATIC RAM
VCC
C12
0.1µF
D00 RESET
R4
10k
D09 RESET
R3
10k
1
A00
A01
A02
A03
A04
A05
A06
A07
A08
A09
A10
A11
A12
A13
VCC
CSBOOT/RDROM
10
9
8
7
6
5
4
3
25
24
21
23
2
26
27
1
22
20
11
12
13
15
16
17
18
19
D08
D09
D10
D11
D12
D13
D14
D15
A0
A1
A2
A3
A4
A5
A6
A7
A8
A9
A10
A11
A12
A13
A14
VPP
OE
CE
DQ0
DQ1
DQ2
DQ3
DQ4
DQ5
DQ6
DQ7
A(00:18)
D(00:15)
U3
27C256
32k x 8-BIT CMOS EPROM
VCC
C11
0.1µF
2
3VCC
A14
Figure 5. 68HC16 Module Schematic (continued)
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
______________________________________________________________________________________ 21
Figure 6. 68HC16 Module Component Placement Guide—Component Side
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
22 ______________________________________________________________________________________
Figure 7. 68HC16 Module PC Board Layout—Component Side
Evaluates: MAX194/MAX195
MAX194 Evaluation System/Evaluation Kit
Maxim cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim product. No circuit patent licenses are
implied. Maxim reserves the right to change the circuitry and specifications without notice at any time.
Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 (408) 737-7600 __________________ 23
© 1995 Maxim Integrated Products Maxim is a registered trademark of Maxim Integrated Products.
Figure 8. 68HC16 Module PC Board Layout—Solder Side
