156 lines
3.4 KiB
C
156 lines
3.4 KiB
C
#include <stdio.h>
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#include <comedilib.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdlib.h>
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/*
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* A little pwm demo
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* Part of Comedilib
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*
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* Copyright (c) 2012 Bernd Porr <berndporr@f2s.com>
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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 <errno.h>
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#include <getopt.h>
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#include <ctype.h>
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#include <string.h>
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#include "examples.h"
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// the option -n is used to switch on/off the pwm
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int main(int argc, char *argv[])
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{
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int ret;
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comedi_insn insn;
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lsampl_t d[5];
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comedi_t *device;
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int freq;
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struct parsed_options options;
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init_parsed_options(&options);
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options.freq = -1;
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// we hijack this option to switch it on or off
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options.n_scan = -1;
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options.value = -1;
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parse_options(&options, argc, argv);
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if ((options.value==-1)&&(options.n_scan==-1)&&(options.freq==-1)) {
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fprintf(stderr,
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"Usage: %s OPTIONS duty_cycle\n"
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"options: \n"
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" -N 0 switches PWM off\n"
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" -N 1 switches PWM on\n"
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" -N 2 enquires the max value for the duty cycle\n"
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" -F FREQ sets the PWM frequency\n",
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argv[0]);
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}
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device = comedi_open(options.filename);
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if(!device){
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comedi_perror(options.filename);
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exit(-1);
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}
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options.subdevice = comedi_find_subdevice_by_type(device,COMEDI_SUBD_PWM,0);
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if (options.verbose)
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printf("PWM subdevice autodetection gave subdevice number %d\n",
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options.subdevice);
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if(options.n_scan==2) {
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printf("%d\n",comedi_get_maxdata(device,options.subdevice,0));
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comedi_close(device);
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exit(0);
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}
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insn.insn=INSN_CONFIG;
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insn.data=d;
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insn.subdev=options.subdevice;
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insn.chanspec=CR_PACK(0,0,0);
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if(options.n_scan==1) {
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d[0] = INSN_CONFIG_ARM;
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d[1] = 0;
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insn.n=2;
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ret=comedi_do_insn(device,&insn);
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if(ret < 0){
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fprintf(stderr,"Could not switch on:%d\n",ret);
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comedi_perror(options.filename);
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exit(-1);
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}
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}
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if(options.n_scan==0) {
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d[0] = INSN_CONFIG_DISARM;
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d[1] = 0;
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insn.n=1;
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ret=comedi_do_insn(device,&insn);
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if(ret < 0){
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fprintf(stderr,"Could not switch off:%d\n",ret);
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comedi_perror(options.filename);
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exit(-1);
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}
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}
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if(options.freq>0) {
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freq = options.freq;
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d[0] = INSN_CONFIG_PWM_SET_PERIOD;
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d[1] = 1E9/freq;
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insn.n=2;
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ret=comedi_do_insn(device,&insn);
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if(ret < 0){
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fprintf(stderr,"Could set frequ:%d\n",ret);
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comedi_perror(options.filename);
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exit(-1);
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}
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}
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d[0] = INSN_CONFIG_GET_PWM_STATUS;
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insn.n=2;
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ret=comedi_do_insn(device,&insn);
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if(ret < 0){
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fprintf(stderr,"Could not get status:%d insn=%d\n",
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ret,
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d[0]);
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comedi_perror(options.filename);
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exit(-1);
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}
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if (options.verbose) {
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if (d[1])
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fprintf(stderr,
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"PWM is on.\n");
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else
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fprintf(stderr,
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"PWM is off.\n");
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}
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d[0] = INSN_CONFIG_PWM_GET_PERIOD;
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insn.n=2;
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ret=comedi_do_insn(device,&insn);
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if(ret < 0){
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fprintf(stderr,"Could get frequ:%d\n",ret);
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comedi_perror(options.filename);
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exit(-1);
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}
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freq = 1E9 / d[1];
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if (options.verbose)
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fprintf(stderr,"PWM frequency is %d\n", freq);
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if (options.value>=0)
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if(comedi_data_write(device,
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options.subdevice,
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options.channel,
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0,
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0,
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options.value)<0)
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{
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fprintf(stderr,"error setting the pwm duty cycle on ");
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comedi_perror(options.filename);
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exit(1);
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}
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return 0;
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}
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