GETTING STARTED:
After installing comedi and comedilib, cd to this directory (comedilib*/demo).
Use ./info for a very first test. If hardware and software are correctly
installed, the program prints a list of subdevices it recognises. If the
device is not /dev/comedi0, you can use the command-line option
'-f <device file>'.
Continue with ./inp -s <subdevice> -c <channel> to read individual samples,
or with ./outp -s <subdevice> -c <channel> <integer value> to set an
output value.
Examples
ao_waveform:
You need a device (and driver) capable of streaming analog output,
which currently is some of the members of the NI AT-MIO and PCI-MIO
E series. Creates a sine wave on an analog output channel.
cmd:
An example for using Comedi commands. Comedi commands
are used for asynchronous acquisition, with the timing controlled
by on-board timers or external events.
dio:
Requirements: A board with a digital I/O subdevice. Not just
a 'digital input' or 'digital output' subdevice, but one in
which the channels can be configured between input and output.
eeprom_dump:
Dumps the EEPROM of a card, if it has one. Useful for debugging
devices/drivers.
info:
Displays some information that Comedi knows about a device.
inp:
Simple input: Reads one sample from one channel on one subdevice.
inpn:
Slightly more complicated input demo. (It has a for() loop.)
Reads each channel on a subdevice, at every possible input
range, and converts the data to a voltage.
insn:
Example showing how to use instructions directly. Not
recommended for beginners: use higher-level functions such
as comedi_data_read(), comedi_data_write(), etc., as demonstrated
in the inp, outp, and dio examples.
ledclock:
Requirements: A board with a digital I/O subdevice. Not just
a 'digital input' or 'digital output' subdevice, but one in
which the channels can be configured between input and output.
main:
This is not a demo. The file main.c contains just an auxiliary
function. See below.
mmap:
Similar to the cmd demo, except the data is obtained through
a memory mapping instead of doing read() on /dev/comediX.
outp:
Write one <value> to one channel of one subdevice.
receiver:
Requirements: A board with a digital I/O subdevice. Not just
a 'digital input' or 'digital output' subdevice, but one in
which the channels can be configured between input and output.
select:
An example for using select() with asynchronous input. This
example requires an asynchronous input subdevice that can
handle TRIG_TIMER as a scan_begin_src.
sender:
Requirements: A board with a digital I/O subdevice. Not just
a 'digital input' or 'digital output' subdevice, but one in
which the channels can be configured between input and output.
sv:
Similar to inp, but measures the input using the comedi_sv_*()
functions, which average many samples to try to get a more accurate
estimate of the actual input.
tut1:
tut2:
Tutorial examples.
Many of these demos are linked with the file main.c, which parses
command line options. Some options don't make sense with all programs.
The options are:
-a <aref> uses analog reference <aref> (default: 0)
-c <chan> uses channel <chan>
-s <subd> uses subdevice <subd>
-r <range> uses voltage range <range>
-f <file> uses device file <file> (default: /dev/comedi0)
-v verbose
-d set analog reference to differential
-g set analog reference to ground
-o set analog reference to other
-m set analog reference to common
