modified to work with TRIG_INT, made it use the -F command line option to

set update frequency

diff --git a/demo/ao_waveform.c b/demo/ao_waveform.c
index b32bd23eda40bd0df0bd1581edfae67b743c5adb..11f82d7cc60c150c01681dc889d1cb3c4f26a5f9 100644 (file)
--- a/demo/ao_waveform.c
+++ b/demo/ao_waveform.c
@@ -58,10 +58,6 @@
 /* frequency of the sine wave to output */
 double waveform_frequency      = 100.0;
 
-/* update rate for the DAC, typically much higher than
-   the frequency of the sine wave. */
-double update_frequency                = 50000.0;
-
 /* peak-to-peak amplitude, in DAC units (i.e., 0-4095) */
 double amplitude               = 4000;
 
@@ -91,6 +87,7 @@ void dds_init_sawtooth(void);
 int main(int argc, char *argv[])
 {
        comedi_cmd cmd;
+       comedi_insn insn;
        int err;
        int n,m;
        int total=0;
@@ -104,16 +101,19 @@ int main(int argc, char *argv[])
        }
 
        dev = comedi_open(filename);
-
+       if(dev == NULL){
+               fprintf(stderr, "error opening %s\n", filename);
+               return -1;
+       }
        subdevice = comedi_find_subdevice_by_type(dev,COMEDI_SUBD_AO,0);
 
        memset(&cmd,0,sizeof(cmd));
        cmd.subdev = subdevice;
        cmd.flags = 0;
-       cmd.start_src = TRIG_NOW;
+       cmd.start_src = TRIG_INT;
        cmd.start_arg = 0;
        cmd.scan_begin_src = TRIG_TIMER;
-       cmd.scan_begin_arg = 1e9/update_frequency;
+       cmd.scan_begin_arg = 1e9/freq;
        cmd.convert_src = TRIG_NOW;
        cmd.convert_arg = 0;
        cmd.scan_end_src = TRIG_COUNT;
@@ -131,14 +131,19 @@ int main(int argc, char *argv[])
        dds_output(data,BUF_LEN);
        dds_output(data,BUF_LEN);
 
-       m=write(comedi_fileno(dev),data,BUF_LEN*sizeof(sampl_t));
-       perror("write");
-       printf("m=%d\n",m);
-
        if ((err = comedi_command(dev, &cmd)) < 0) {
                comedi_perror("comedi_command");
                exit(1);
        }
+
+       m=write(comedi_fileno(dev),data,BUF_LEN*sizeof(sampl_t));
+       perror("write");
+       printf("m=%d\n",m);
+       
+       memset(&insn, 0, sizeof(comedi_insn));
+       insn.insn = INSN_INTTRIG;
+       comedi_do_insn(dev, &insn);
+
        while(1){
                dds_output(data,BUF_LEN);
                n=BUF_LEN*sizeof(sampl_t);
@@ -174,7 +179,7 @@ void dds_init(void)
 {
        int i;
 
-       adder=waveform_frequency/update_frequency*(1<<16)*(1<<WAVEFORM_SHIFT);
+       adder=waveform_frequency/freq*(1<<16)*(1<<WAVEFORM_SHIFT);
 
        dds_init_function();