General Description
The MAX147 evaluation system (EV system) is a com-
plete, low-cost, 8-channel data-acquisition system con-
sisting of a MAX147 evaluation kit (EV kit) and a Maxim
68HC16 or 80C32 microcontroller (C) module. IBM
PC-compatible software provides a handy user inter-
face to exercise the MAX147's features. Source code is
provided.
Order the EV system for comprehensive evaluation of
the MAX147 using a personal computer. Order the EV
kit if the 68HC16 or 80C32 C module was purchased
previously with another Maxim EV system, or for custom
use in other C-based systems.
The MAX147 EV kit evaluates both the MAX147 and the
MAX146. To evaluate the MAX146, order a free sample
of the MAX146BCPP along with the MAX147 EV kit.
Features
Proven PC Board Layout
Complete Evaluation System
Convenient Test Points Provided On-Board
Data-Logging Software
Source Code Provided
Fully Assembled and Tested
Evaluates: MAX146/MAX147
MAX147 Evaluation System/Evaluation Kit
________________________________________________________________
Maxim Integrated Products
1
19-4751; Rev 2; 7/98
PART
TEMP. RANGE
BOARD TYPE
MAX147EVKIT-DIP
0C to +70C
Through-Hole
QTY
DESCRIPTION
C1, C7C14
9
C2, C4, C6,
C15, C17C20
8
C3
1
4.7F tantalum capacitor
0.1F ceramic capacitors
0.01F ceramic capacitors
DESIGNATION
Component List
Ordering Information
MAX147EVC16
System Component List
MAX147EVC32
System Component List
C5
1
10F tantalum capacitor
C16
1
0.047F ceramic capacitor
J1
1
2x20 right-angle socket
J18
1
10-pin header
JU1, JU2, JU5
3
2-pin jumpers
R1R8
8
1k
, 5% resistors
R9
1
10k
, 5%, 10-pin SIP resistor pack
R10R13
0
Open
R14
1
220k
, 5% resistor
R15
1
180k
, 5% resistor
R16
1
100k
trim pot
R17, R21
2
1M
, 5% resistors
R18
1
100
, 5% resistor
U1
1
Maxim MAX147BCPP
U2
1
Maxim MAX872CPA
MAX147EVC16-DIP
0C to +70C
Through-Hole
MAX147EVC32-DIP
0C to +70C
Through-Hole
QTY
DESCRIPTION
1
80C32 C Module (80C32MODULE-DIP)
1
MAX147 Evaluation Kit (MAX147EVKIT-DIP)
QTY
DESCRIPTION
1
68HC16 C Module (68HC16MODULE-DIP)
1
MAX147 Evaluation Kit (MAX147EVKIT-DIP)
U3
1
Maxim MAX393CPE
U4
1
Maxim MAX666CPA
U5
1
Maxim MAX495CPA
U6
1
74HCT04
U7
1
Maxim MAX494CPD
None
1
PC board
None
1
Software disk, MAX147 Evaluation Kit
MAX147 Stand-Alone EV Kit
The MAX147 EV kit provides a proven PC board layout
to facilitate evaluation of the MAX147. It must be
interfaced to appropriate timing signals for proper
operation. Refer to the MAX147 data sheet for timing
requirements.
The MAX147 EV kit operates with either a 3V supply or
a 5V supply. The EV kit's own 3V regulator is powered
by a user-supplied 5V source. Trim pot R16 sets the
actual 3V voltage. R16 is adjustable from approximately
2.3V to 3.6V.
If a 3V power supply is already in use, disable the on-
board 3V regulator by unplugging the MAX666 from its
socket. Then connect the 3V supply to the VDD input
pad.
For free samples & the latest literature: http://www.maxim-ic.com, or phone 1-800-998-8800.
For small orders, phone 408-737-7600 ext. 3468.
Evaluates: MAX146/MAX147
MAX147 Evaluation System/Evaluation Kit
2
_______________________________________________________________________________________
3V-Only Systems
For 3V systems, unplug the MAX666 regulator and con-
nect your 3V power supply to the VDD input pad.
Connect the 3V and 5V input pads to each other to
power the MAX393. (The MAX393 can be powered with
3V or 5V. See
Detailed Description of Hardware sec-
tion.) For development flexibility, the EV kit uses a
MAX393 to route the EXTCOM signal to COM or to the
CH0 input. Obtain the 3V DOUT and SSTRB signals
from the header J18, not from the 40-pin connector
(3V-only systems do not require the 74HCT04 level
translator).
Systems Using 5V Logic
For 5V-logic systems, the 74HCT04 translates the
MAX147's 3V outputs to 5V levels. The MAX147's input
may be driven directly by 5V logic levels (obtain the 5V
DOUT and SSTRB signals from the 40-pin connector).
For 5V-only applications, refer to the MAX186/MAX188
analog-to-digital converters.
MAX147 EV System
The MAX147 EV system operates from a user-supplied
9V to 20V DC power supply, from which it generates a
5V supply for the C board. A 3V regulator supplies
power to the MAX147. 3V to 5V level translators are
provided to interface the MAX147 with the C board.
Quick Start
1)
Copy the files from the distribution disk to your
hard disk or to blank floppy disks. Make sure that
the MAX147 EV kit software is in its own directory.
The necessary files are in the root directory of the
distribution disk, and the source code is in the
SOURCE subdirectory. The SOURCE subdirectory
is not required to operate the EV system.
2)
Carefully connect the boards by aligning the
MAX147 EV kit's 40-pin header with the C mod-
ule's 40-pin connector. Gently press them together,
so that they are flush against one another.
3)
Connect a 9V to 15V DC power source to the C
module at the terminal block. This is located next to
the on/off switch, in the upper-right corner of the C
module. Observe the polarity marked on the board.
4)
Connect a cable from the computer's serial port to
the C module. For a 9-pin serial port, use a
straight-through, 9-pin female-to-male cable. If the
only available serial port uses a 25-pin connector,
a standard 25-pin to 9-pin adapter is required.
The EV kit software checks the modem status
lines (CTS, DSR, DCD) to confirm that the correct
port is selected.
5)
Start the MAX147 software on the IBM PC by setting
the current directory to match the directory contain-
ing the Maxim programs, then type the program
name
MAX147. Do not turn off or disconnect the C
module while the program is running; if you do, you
will have to restart the program.
6)
The program asks which C module is in use and
to which port it is connected (the default C is the
68HC16). For the 80C32 C module, press C to
select the 80C32. Press the space bar until the
correct PC serial port is highlighted, and press
ENTER. The MAX147 program is now in terminal-
emulation mode.
7)
Turn on the C module's power. The module dis-
plays its log-on banner and tests its RAM.
8)
Download and run the RAM resident program on
the C module by pressing ALT+L (i.e., hold down
the ALT key as you strike the L key). The program
prompts you for the file name. Press the ENTER
key to download and run the file.
9)
Press ALT+C to switch to the control panel screen
after the RAM resident program is successfully
downloaded.
10) Apply input signals to the CH0CH7 inputs at the
top edge of the MAX147 EV kit board. Observe
the readout on the screen. Table 3 lists the com-
mands available from the control panel screen.
11) Before turning off power to the MAX147 EV kit, exit
the program by pressing ALT+X.
Evaluating the MAX146
To evaluate the MAX146, turn off power to the EV kit,
remove the MAX147 IC, and replace it with a
MAX146BCPP. Disable the external reference by
removing jumpers JU2 and JU5. Type
MAX147 146 to
start the software.
Detailed Description
_________________________of Software
Shutdown Power Cycling (MAX147)
From the control panel, use the up/down arrow keys to
select the power cycling mode. Power cycling puts the
MAX147 in powerdown (FULLPD) mode between
readings. The MAX147 is always fully powered during
conversions.
Shutdown Power Cycling (MAX146)
From the control panel, use the up/down arrow keys to
select the power cycling mode. The MAX146 supports
FULLPD mode as well as FASTPD mode, where the
Evaluates: MAX146/MAX147
MAX147 Evaluation System/Evaluation Kit
_______________________________________________________________________________________
3
internal 1.2V bandgap reference remains active. The
MAX146 is always fully powered during conversions.
Low-Speed Data Logging
The RS-232 serial link limits the data-logging sample
rate to no more than 10sps (samples per second). The
data-logging command is used to write data to a user-
specified file in plain comma-spaced-value text format.
From the control panel screen, press L. If a log file is
not already open, the software asks for a file name.
Only one log file is allowed per session. Once a log file
is open, press L to toggle data logging on or off.
With data logging enabled, "Logging" flashes on the
screen. One complete line of data is written after all
enabled channels are sampled.
The first line of the log file contains the column head-
ings. Each subsequent line of the log file contains all
eight channels, separated by commas. The values are
written as raw decimal output codes or as scaled volt-
ages, depending on which setting the control panel is
currently displaying. Use the C and V commands to
select the display format (Table 3). F3, the log data
marker command, can be used to sequentially tag dif-
ferent sections of the log file to indicate a change in
setup or input conditions. Pressing F3 writes an extra
entry at the end of the current line of the data log, to
indicate a change in setup or input conditions.
High-Speed Data Sampling
The S command samples rates over 10 samples per
second (sps). Data is collected from only one of the
eight channels at a rate from 100sps to 91ksps. First,
select the channel by pressing one of the number keys
07. Next, press F to specify the name of the file into
which the samples should be written. If the file already
exists, the screen displays "*** file already exists ***".
To begin collecting data, press B. After the samples are
collected, the data is automatically uploaded to the
host and stored in the sample file.
Controlling the Sampling Rate
The rate for high-speed sampling, data logging, and
the oscilloscope demo mode (Table 3, key O) is con-
trolled by the D (delay between samples) command.
When used with the sample or oscilloscope demo com-
mands, specify the approximate delay in microseconds
or milliseconds by typing D, then the number, then "sec"
or "msec". Always verify timing by using an oscilloscope,
since this delay is not linear due to code overhead. The
fast sampling screen and oscilloscope demo mode use
delays from 100s to 1000s. The 68HC16 software sup-
ports delays between 68s and 1000ms. The 80C32 soft-
ware supports delays between 450s and 70ms.
When used with the slower data-logging command,
specify the delay in seconds. The delay is between
enabled channels, and one line of data is logged after
all enabled channels have been polled.
COM Voltage
COM is connected to ground (default) or to a user-
supplied analog common voltage applied to the
EXTCOM input pad. Press F6 to select the desired
COM connection.
The EV kit software can measure a user-applied COM
voltage. When F4 is pressed from the control panel
screen (Table 3), the software connects the EXTCOM
input pad to input channel 0. Next, the software con-
nects COM to ground. The channel 0 voltage is mea-
sured in single-ended unipolar mode. The measure-
ment is performed several times and averaged. After
measuring the external COM pad voltage, the switches
are restored to their previous configuration.
Operating with QSPI,
24 Bits per Transfer
The EV kit software program KIT147.S19 loaded into
the 68HC16 module uses a 24-bits-per-transfer mode,
which operates at 59ksps throughput. Refer to the tim-
ing diagrams in the
Clock Modes section of the
MAX147 data sheet.
Table 1. Recommended QSPI Setup
Parameters for 24 Bits per Transfer
(used in KIT147.S19)
0100 xxx0 (16-bit enable)
CR1
Received data, left justified, with one lead-
ing zero bit
RR1
External clock: 1000 xxx0 (hold CS low).
Internal clock: 1010 xxx0 (hold CS low; DT
delay after transfer).
CR0
0000 0000 1xxx xxyy (configure and start
conversion)
TR0
0000 0000 0000 0000 (read data)
4 (7.6s delay used in internal clock mode)
DTL
TR1
16 (when enabled)
BITS
0 (data is stable on clock rising edge)
CPHA
0 (clock is idle low)
CPOL
5 (1.68MHz)
SPBR
VALUE
PARAMETER
Evaluates: MAX146/MAX147
MAX147 Evaluation System/Evaluation Kit
4
_______________________________________________________________________________________
Operating with QSPI,
16 Bits per Transfer
The program KIT14716.S19 demonstrates the 16-bits-
per-transfer interface scheme, which operates at 91ksps
throughput. In this demonstration, CS is held low and
the QSPI operates continuously in the background.
Refer to the timing diagrams in the
Clock Modes section
of the MAX147 data sheet. To use this program, follow
the instructions in
Quick Start, but in step 8, download
KIT14716.S19 instead of KIT147.S19. After loading,
press ALT+C to switch to the control panel.
Changing the Reference Voltage
The MAX147 EV kit software assumes a 2.5V reference
voltage, unless otherwise specified. When using a refer-
ence value other than 2.5V, specify the value when start-
ing the program. For example, if VREF is driven by a
2.048V reference, start the MAX147 software by typing:
MAX147 VREF 2.048
Or, on the MAX146, if REFADJ is driven by a 1.2V refer-
ence, start the MAX147 software by typing:
MAX147 146 REFADJ 1.2
The external reference's temperature coefficient must
be 20ppm/C or less to achieve accuracy to within four
LSBs over the 0C to +70C temperature range. For
12-bit accuracy over the 0C to +70C range, the refer-
ence's temperature coefficient must be 4ppm/C or less.
The MAX146 can use either its internal reference or an
external reference. On the EV kit, the internal reference
has been disabled by pulling REFADJ up to VDD (JU2)
and driving VREF with a MAX872 2.5V reference (JU5).
For lowest component count, enable the MAX146's inter-
nal reference by removing the shunts from JU2 and
JU5. This enables the internal bandgap reference and
the reference buffer, driving VREF internally to 2.5V. A
0.01F ceramic bypass capacitor near REFADJ (C1 on
the EV kit) provides noise filtering for the bandgap
reference.
Detailed Description
of Hardware
The MAX147 EV kit board includes a MAX666, config-
ured as a 3V regulator. Trim pot R16 adjusts the VDD
voltage between 2.3V and 3.6V.
The MAX872 is a micropower 2.5V reference.
The MAX494 and MAX495 are low-voltage, rail-to-rail op
amps with 500kHz gain-bandwidth product. The
MAX495 buffers the external COM input source. The
MAX494 can be used to buffer some of the input signals.
The MAX393 analog switch allows the EV kit software to
route the MAX147 COM pin to ground or to the external
COM input. In addition, the external COM input can be
routed to input channel 0. Typical systems connect
COM directly to analog ground or the analog common
voltage. The MAX393 can be powered by 3V, but if
driven by 5V logic (as is the case with the EV system), it
must be powered by 5V.
The 74HCT04 translates the DOUT and SSTRB signals
from 3V to 5V logic levels for interfacing to the C mod-
ule. The MAX147's logic inputs can be driven directly
from 5V logic levels.
Input-Signal Buffering
The analog-to-digital converter (ADC) inputs require a
sufficiently low-impedance source for specified accura-
cy. An ADC can inject a small amount of charge at the
start of the acquisition time, and the source signal must
recover to within the desired accuracy before the
acquisition time ends. If the source by itself cannot do
this, use an op amp to buffer the input signal.
To buffer the CH4CH7 input signals, unplug the 14-pin
header from U7, and install the supplied MAX494 quad
op amp in its place. Note the location of pin 1 toward
the upper right corner of the board.
When using an input buffer, the buffer output cannot
reach the power-supply rails.
If the MAX494 op-amp
buffer is installed and the input to the buffer is
grounded, the buffered output will not reach
ground.
The MAX494 allows its output signal to go to
within approximately 50mV of either supply.
Table 2. Recommended QSPI Setup
Parameters for 16 Bits per Transfer
(used in KIT14716.S19)
Received data, left justified
RR0
External clock: 1100 xxx0 (16-bit transfer).
Internal clock: 1110 xxx0 (16-bit transfer
with DT delay).
CR0
0000 0001 xxxx xyy0 (configure and start
conversion)
TR0
4 (7.6s delay used in internal clock mode)
DTL
16
BITS
0 (clock is idle low)
CPOL
0 (data is stable on clock rising edge)
5 (1.68MHz)
SPBR
CPHA
VALUE
PARAMETER
Evaluates: MAX146/MAX147
MAX147 Evaluation System/Evaluation Kit
_______________________________________________________________________________________
5
KEY
FUNCTION
0, 1, 2, 3,
4, 5, 6, 7
Enables or disables the corresponding input channel 0, 1, 2, 3, 4, 5, 6, or 7. The EV kit software scans all enabled
channels.
F3
Writes a marker into the data-log file.
S
Samples one of the eight inputs at high speed. The sampling rate is controlled by the P and D delays. Due to pro-
gram overhead, the O and S commands operate at different rates. Timing should be verified with an oscilloscope.
V
Displays the conversion results in volts.
F1
Chooses input scale (unipolar, bipolar, unipolar differential, bipolar differential) for all enabled channels. Disabled
channels are unaffected.
Table 3. MAX147 EV Kit Command Reference
F4
Measures the value of a user-applied COM voltage.
F5
Changes the assumed value of VREF.
F6
Changes the assumed voltage at COM. Selecting G connects the COM pin to ground; selecting E connects the
COM pin to the EXTCOM input pad.
F7
Internal clock mode
F8
External clock mode
ALT+T
Switches back to terminal mode.
ALT+X
Exits to DOS.
Selects power-down mode.
P
Power-up delay. Timing is approximate and should be verified with an oscilloscope. When using an external refer-
ence, power-up delay is not necessary and should be set to zero. Power-up delay is used regardless of which
power-cycling mode is selected.
O
Oscilloscope demo. Samples are collected and discarded as fast as possible. Observe waveforms and timing with
an oscilloscope.
L
Enables or disables data logging. If the -L command-line option was not specified, the L command prompts for a
log-file name.
D
Delay between samples. Delays longer than one second are handled by the IBM PC; otherwise, the C module han-
dles the delay. Timing is approximate and should be verified with an oscilloscope.
C
Displays the conversion results in decimal form.
,
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