df6a97ec6c
also updated the tutorial. I've simplified the tut2.c by using comedi2phys instead of comedi2physical. The use of polynomials as a 2nd comedi program is a bit too difficult for a novice and might deter the user to dig deeper into the coding. Also, I've added tut3.c which is a stripped down version of cmd.c and of that again the relevant lines for the handbook to save space.
69 lines
1.8 KiB
C
69 lines
1.8 KiB
C
/*
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* Tutorial example #2
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* Part of Comedilib
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*
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* Copyright (c) 1999,2000 David A. Schleef <ds@schleef.org>
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* Copyright (c) 2008 Frank Mori Hess <fmhess@users.sourceforge.net>
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*
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* This file may be freely modified, distributed, and combined with
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* other software, as long as proper attribution is given in the
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* source code.
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*/
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#include <stdio.h> /* for printf() */
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#include <stdlib.h>
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#include <comedilib.h>
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#include <ctype.h>
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#include <math.h>
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int subdev = 0; /* change this to your input subdevice */
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int chan = 0; /* change this to your channel */
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int range = 0; /* more on this later */
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int aref = AREF_GROUND; /* more on this later */
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const char filename[] = "/dev/comedi0";
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int main(int argc, char *argv[])
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{
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comedi_t *device;
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lsampl_t data;
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double physical_value;
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int retval;
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comedi_range * range_info;
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lsampl_t maxdata;
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device = comedi_open(filename);
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if(device == NULL)
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{
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comedi_perror(filename);
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return -1;
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}
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retval = comedi_data_read(device, subdev, chan, range, aref, &data);
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if(retval < 0)
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{
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comedi_perror(filename);
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return -1;
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}
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comedi_set_global_oor_behavior(COMEDI_OOR_NAN);
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range_info = comedi_get_range(device, subdev, chan, range);
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maxdata = comedi_get_maxdata(device, subdev, chan);
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printf("[0,%d] -> [%g,%g]\n", maxdata,
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range_info->min, range_info->max);
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physical_value = comedi_to_phys(data, range_info, maxdata);
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if(isnan(physical_value)) {
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printf("Out of range [%g,%g]",
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range_info->min, range_info->max);
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} else {
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printf("%g", physical_value);
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switch(range_info->unit) {
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case UNIT_volt: printf(" V"); break;
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case UNIT_mA: printf(" mA"); break;
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case UNIT_none: break;
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default: printf(" (unknown unit %d)",
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range_info->unit);
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}
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printf(" (%lu in raw units)\n", (unsigned long)data);
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}
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return 0;
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}
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