MAX197EVKIT-DIP Maxim Integrated, MAX197EVKIT-DIP Datasheet - Page 7

• Manufacturer Part Number: MAX197EVKIT-DIP
• Description: Data Conversion IC Development Tools Programmers, Development Systems
• Manufacturer: Maxim Integrated
• Series: MAX197r

Specifications of MAX197EVKIT-DIP

• Interface Type: Parallel
• Factory Pack Quantity: 1

From the control panel, use the up/down arrow keys to
select the power-down mode. STANDBY power
cycling puts the MAX197 in standby mode between
readings, and FULLPD turns off everything except the
2.5V bandgap reference. The MAX197 is always fully
powered during conversions. The MAX197’s shutdown
pin can be used to put the device into FULLPD mode.
When using FULLPD or SHDN, a power-up delay may
be necessary to allow the reference buffer time to
recharge. From the control panel, use the “P” com-
mand to set this power-on delay. The 68HC16 software
allows delays between 68µs and 6000µs. The 80C32
software allows delays between 8µs and 65535µs. A
value of 0 disables the delay. Refer to the Typical
Timing Characteristics to see the relationship between
the value selected on the corresponding power-up
delay.
The RS-232 serial link limits the data logging sample
rate to no more than 10sps (samples per second). The
data logging command can be 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 will ask for a file
name. Only one log file is allowed per session. Once a
log file has been opened, pressing L toggles data log-
ging on or off. While data logging is enabled, the word
“Logging” will flash on the screen. One complete line
of data is written to the log file after all enabled chan-
nels have been 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 (see Table 1). 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, which
can be useful for indicating a change in setup or input
conditions.
_______________________________________________________________________________________
Shutdown Power Cycling
Low-Speed Data Logging
MAX197 Evaluation Kit
For sampling rates over 10sps, the S command can be
used. Data can be collected from only one of the eight
channels at a rate from 100sps up to 45ksps for the
68HC16 module (10sps to 10ksps for the 80C32 mod-
ule). First, select the channel by pressing one of the
number keys 0–7. Next, press F to specify the name of
the file into which the samples should be written. If the
file already exists, the screen will say “*** file already
exists***”. To begin collecting data, press B. After 1024
samples have been collected, the data is automatically
uploaded to the host and stored in the sample file.
The rate for high-speed sampling, data logging, and the
oscilloscope demo mode (see Table 1, 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
by typing D, the approximate delay time, then “usec”.
Refer to the Typical Timing Characteristics to see the
relationship between the value selected and the corre-
sponding delay between samples. Due to code over-
head, this delay is not perfectly linear, so timing should
always be verified using an oscilloscope. The fast
sampling screen and oscilloscope demo mode use
delays on the order of 100µs to 1000µs. The 80C32
software supports delays between 24µs and 73ms, but
the 68HC16 software only supports delays between
68µs and 6000µs.
When used with the slower data-logging command,
specify the delay in seconds. This delay is defined as
the time between two consecutive conversions.
The tare command is used to compensate in software
for the offset voltage. Connect the channel 0 input pin
to ground (or, if driving with an op amp, connect the
channel 0 op amp’s input to ground instead). The “T”
command measures the offset voltage on channel 0
and subtracts that offset from all subsequent readings
on all channels. The tare command is canceled by
pressing CTRL+T.
Tare Command (software offset null)
Controlling the Sampling Rate
High-Speed Data Sampling
7