/*
* This part of the demo measures channels 1, 2, 3, 4 at a rate of
* 10 khz, with the inter-sample time at 10 us (100 khz). The number
* of scans measured is 10. This is analogous to the old mode2
* acquisition.
*/
void do_cmd_1(comedi_t *dev, int subdevice)
{
comedi_cmd cmd;
memset(&cmd,0,sizeof(cmd));
/* the subdevice that the command is sent to */
cmd.subdev = subdevice;
/* flags */
cmd.flags = TRIG_WAKE_EOS;
cmd.start_src = TRIG_NOW;
cmd.start_arg = 0;
cmd.scan_begin_src = TRIG_TIMER;
cmd.scan_begin_arg = msec_to_nsec(100);
#if 1
cmd.convert_src = TRIG_TIMER;
cmd.convert_arg = 1;
#else
cmd.convert_src = TRIG_ANY;
cmd.convert_arg = 0;
#endif
cmd.scan_end_src = TRIG_COUNT;
cmd.scan_end_arg = 1;
cmd.stop_src = TRIG_NONE;
cmd.stop_arg = 0;
cmd.chanlist = chanlist;
cmd.chanlist_len = 1;
chanlist[0]=CR_PACK(0,0,0);
do_cmd(dev,&cmd);
}
/*
* This part of the demo measures channels 1, 2, 3, 4 at a rate of
* 10 khz, with the inter-sample time at 10 us (100 khz). The number
* of scans measured is 10. This is analogous to the old mode2
* acquisition.
*/
void prepare_cmd(comedi_t *dev, comedi_cmd *cmd, int subdevice)
{
memset(cmd,0,sizeof(*cmd));
/* the subdevice that the command is sent to */
cmd->subdev = subdevice;
/* flags */
cmd->flags = 0;
/* each event requires a trigger, which is specified
by a source and an argument. For example, to specify
an external digital line 3 as a source, you would use
src=TRIG_EXT and arg=3. */
/* In this case, we specify using TRIG_NOW to start
* acquisition immediately when the command is issued.
* The argument of TRIG_NOW is "number of nsec after
* NOW", but no driver supports it yet. Also, no driver
* currently supports using a start_src other than
* TRIG_NOW. */
cmd->start_src = TRIG_NOW;
cmd->start_arg = 0;
/* The timing of the beginning of each scan is controlled
* by scan_begin. TRIG_TIMER specifies that scan_start
* events occur periodically at a rate of scan_begin_arg
* nanoseconds between scans. */
cmd->scan_begin_src = TRIG_TIMER;
cmd->scan_begin_arg = msec_to_nsec(100);
/* The timing between each sample in a scan is controlled
* by convert. Like above, TRIG_TIMER specifies that
* convert events occur periodically at a rate of convert_arg
* nanoseconds between scans. */
cmd->convert_src = TRIG_TIMER;
cmd->convert_arg = msec_to_nsec(1);
/* The end of each scan is almost always specified using
* TRIG_COUNT, with the argument being the same as the
* number of channels in the chanlist. You could probably
* find a device that allows something else, but it would
* be strange. */
cmd->scan_end_src = TRIG_COUNT;
cmd->scan_end_arg = n_chans; /* number of channels */
/* The end of acquisition is controlled by stop_src and
* stop_arg. The src will typically be TRIG_COUNT or
* TRIG_NONE. Specifying TRIG_COUNT will stop acquisition
* after stop_arg number of scans, or TRIG_NONE will
* cause acquisition to continue until stopped using
* comedi_cancel(). */
cmd->stop_src = TRIG_COUNT;
cmd->stop_arg = n_scans;
/* the channel list determined which channels are sampled.
In general, chanlist_len is the same as scan_end_arg. Most
boards require this. */
cmd->chanlist = chanlist;
cmd->chanlist_len = n_chans;
}
