Created a PWM demo using the newly introduced defines to

manipulate PWM frequency.

diff --git a/demo/Makefile.am b/demo/Makefile.am
index 523d3eb702ae6edebdf220d08c4c2f99e8c03c83..8e87f2b2abe48f02fd9fe4ad5bcb579ded4aedb3 100644 (file)
--- a/demo/Makefile.am
+++ b/demo/Makefile.am
@@ -4,7 +4,7 @@ noinst_PROGRAMS = \
        choose_routing cmd do_waveform dio eeprom_dump gpct_buffered_counting \
        gpct_encoder gpct_pulse_generator \
        gpct_simple_counting inp inpn insn ledclock \
-       mmap outp poll receiver select \
+       mmap outp poll receiver select pwm \
        sender sigio sv tut1 tut2 tut3
 
 noinst_HEADERS = examples.h
@@ -101,6 +101,11 @@ poll_SOURCES = poll.c common.c
 poll_CFLAGS = $(COMEDILIB_CFLAGS)
 poll_LDADD = $(COMEDILIB_LIBS)
 
+pwm_SOURCES = pwm.c common.c
+pwm_CFLAGS = $(COMEDILIB_CFLAGS)
+pwm_LDADD = $(COMEDILIB_LIBS)
+
+
 receiver_SOURCES = receiver.c common.c
 receiver_CFLAGS = $(COMEDILIB_CFLAGS)
 receiver_LDADD = $(COMEDILIB_LIBS)

diff --git a/demo/README b/demo/README
index 92381867bb26a7af49c2d4cb3edc7788a6bb3170..b870db0db2bb26dbe1a4a3b5617f2d9e09cd6406 100644 (file)
--- a/demo/README
+++ b/demo/README
@@ -136,6 +136,11 @@ outp <value>:
        Write one <value> to one channel of one subdevice.  Requires
        a digital or analog output subdevice.
 
+pwm:
+       controls PWM devices. Use the option -N 0 and -N 1 to switch
+       it on / off respectively. Call with no arguments to get
+       a help screen.
+
 receiver:
        This demo is meant to be used in conjunction with the sender
        demo.  Receiver requires a digital input subdevice, and sender

diff --git a/demo/pwm.c b/demo/pwm.c
new file mode 100644 (file)
index 0000000..ede2ec7
--- /dev/null
+++ b/demo/pwm.c
@@ -0,0 +1,156 @@
+#include <stdio.h>
+#include <comedilib.h>
+#include <fcntl.h>
+#include <unistd.h>
+#include <stdlib.h>
+/*
+ * A little pwm demo
+ * Part of Comedilib
+ *
+ * Copyright (c) 2012 Bernd Porr <berndporr@f2s.com>
+ *
+ * This file may be freely modified, distributed, and combined with
+ * other software, as long as proper attribution is given in the
+ * source code.
+ */
+
+#include <errno.h>
+#include <getopt.h>
+#include <ctype.h>
+#include <string.h>
+#include "examples.h"
+
+// the option -n is used to switch on/off the pwm
+
+int main(int argc, char *argv[])
+{
+        int ret,i;
+       comedi_insn insn;
+       lsampl_t d[5];
+       comedi_t *device;
+
+        int freq;
+
+       struct parsed_options options;
+
+       init_parsed_options(&options);
+       options.freq = -1;
+       // we hijack this option to switch it on or off
+       options.n_scan = -1;
+       options.value = -1;
+       parse_options(&options, argc, argv);
+
+       if ((options.value==-1)&&(options.n_scan==-1)&&(options.freq==-1)) {
+               fprintf(stderr,
+                       "Usage: %s OPTIONS duty_cycle\n"
+                       "options: \n"
+                       "     -N 0    switches PWM off\n"
+                       "     -N 1    switches PWM on\n"
+                        "     -N 2    enquires the max value for the duty cycle\n"
+                       "     -F FREQ sets the PWM frequency\n",
+                       argv[0]);
+       }
+
+        device = comedi_open(options.filename);
+        if(!device){
+               comedi_perror(options.filename);
+               exit(-1);
+        }
+
+       options.subdevice = comedi_find_subdevice_by_type(device,COMEDI_SUBD_PWM,0);
+       if (options.verbose)
+               printf("PWM subdevice autodetection gave subdevice number %d\n",
+                      options.subdevice);
+
+       if(options.n_scan==2) {
+               printf("%d\n",comedi_get_maxdata(device,options.subdevice,0));
+               close(device);
+               exit(0);
+       }       
+
+       insn.insn=INSN_CONFIG;
+       insn.data=d;
+       insn.subdev=options.subdevice;
+       insn.chanspec=CR_PACK(0,0,0);
+
+       if(options.n_scan==1) {
+               d[0] = INSN_CONFIG_ARM;
+               d[1] = 0;
+               insn.n=2;
+               ret=comedi_do_insn(device,&insn);
+               if(ret < 0){
+                       fprintf(stderr,"Could not switch on:%d\n",ret);
+                       comedi_perror(options.filename);
+                       exit(-1);
+               }
+       }
+       if(options.n_scan==0) {
+               d[0] = INSN_CONFIG_DISARM;
+               d[1] = 0;
+               insn.n=1;
+               ret=comedi_do_insn(device,&insn);
+               if(ret < 0){
+                       fprintf(stderr,"Could not switch off:%d\n",ret);
+                       comedi_perror(options.filename);
+                       exit(-1);
+               }
+       }
+       if(options.freq>0) {
+               freq = options.freq;
+               d[0] = INSN_CONFIG_PWM_SET_PERIOD;
+               d[1] = 1E9/freq;
+               insn.n=2;
+               ret=comedi_do_insn(device,&insn);
+               if(ret < 0){
+                       fprintf(stderr,"Could set frequ:%d\n",ret);
+                       comedi_perror(options.filename);
+                       exit(-1);
+               }
+       }
+               
+       d[0] = INSN_CONFIG_GET_PWM_STATUS;
+       insn.n=2;
+       ret=comedi_do_insn(device,&insn);
+       if(ret < 0){
+               fprintf(stderr,"Could not get status:%d insn=%d\n",
+                       ret,
+                       d[0]);
+               comedi_perror(options.filename);
+               exit(-1);
+       }
+       if (options.verbose) {
+               if (d[1])
+                       fprintf(stderr,
+                               "PWM is on.\n");
+               else
+                       fprintf(stderr,
+                               "PWM is off.\n");
+       }
+       d[0] = INSN_CONFIG_PWM_GET_PERIOD;
+       insn.n=2;
+       ret=comedi_do_insn(device,&insn);
+       if(ret < 0){
+               fprintf(stderr,"Could get frequ:%d\n",ret);
+               comedi_perror(options.filename);
+               exit(-1);
+       }
+       freq = 1E9 / d[1];
+       if (options.verbose)
+               fprintf(stderr,"PWM frequency is %d\n", freq);
+
+       if (options.value>=0)
+
+               if(comedi_data_write(device,
+                                    options.subdevice, 
+                                    options.channel,
+                                    0,
+                                    0,
+                                    options.value)<0)
+               {
+                       fprintf(stderr,"error setting the pwm duty cycle on ");
+                       comedi_perror(options.filename);
+                       exit(1);
+               }
+
+        return 0;
+}