rewrite

diff --git a/demo/mode2.c b/demo/mode2.c
index 45013e3f8d5ca8f9bc0a7b25c4244cad9e1b78c1..fd17b433fb4c2df9d80af2318ab23bfab7f7672a 100644 (file)
--- a/demo/mode2.c
+++ b/demo/mode2.c
@@ -1,15 +1,17 @@
 /*
-   A little input demo for mode 2
+   A little input demo for mode 4
 
-   Mode 2 uses two different timers to convert samples.
-   The primary timer determines the time between scans,
-   and the secondary timer determines the time between
-   samples in a scan.
+   Mode 4 uses an external trigger to repeatedly trigger a
+   scan of samples.  (This is different from mode 3, which
+   triggers an individual sample.)  Thus, for each external
+   trigger, n_chan samples are converted.
 
-   The time between scans is in trigval; the time
-   between samples is selected by trigval1.  Conversion
-   from seconds or Hz is done using the standard timer
-   routines.
+   If you have multiple external trigger lines, the
+   particular trigger line is selected by trigval.
+
+   The time between samples in a scan is selected
+   by trigval1.  Conversion from seconds or Hz is done
+   using the standard timer routines.
 
  */
 
@@ -22,41 +24,62 @@
 #include <getopt.h>
 #include <ctype.h>
 
-#define N_SCANS                10
-#define N_CHANS                16
+#define N_SCANS                4
+#define N_CHANS                4
 
 int subdevice = 0;
-int chan=0;
-int range = 0;
-int aref = AREF_GROUND;
+int channels[N_CHANS] = { 0, 1, 2, 3 };
 double freq = 1000;
+int range = 0;
+int aref = 3;
+int external_trigger_number = 0;
 
-#define N_SAMPLES      1000
+#define N_SAMPLES      (N_CHANS*N_SCANS)
 
-double data[N_SAMPLES];
+sampl_t data[N_SAMPLES];
 
 
 int main(int argc, char *argv[])
 {
        char *fn = NULL;
-       int i;
+       comedi_trig it;
+       int err;
+       int n,i;
        comedi_t *dev;
+       double actual_freq;
+       unsigned int chan[N_CHANS];
 
-       fn = "/dev/comedi0";
+       fn = "/dev/comedi3";
 
        dev = comedi_open(fn);
 
-#if 0
-       for(i=0;i<10;i++){
-               range=comedi_find_range(dev,subdevice,chan,0,-i,i);
-               printf("%d\n",range);
+       it.subdev = 0;
+       it.mode = 2;
+       it.flags = 0;
+       it.n_chan = 1;
+       it.chanlist = chan;
+       it.data = data;
+       it.n = N_SCANS;
+       it.trigsrc = 0;
+       it.trigvar = 10000;
+       it.trigvar1 = 10000;
+
+       /* pack the channel list */
+       for(i=0;i<N_CHANS;i++){
+               chan[i] = CR_PACK(channels[i], range, aref);
+       }
+
+       if ((err = comedi_trigger(dev, &it)) < 0) {
+               perror("ioctl");
+               exit(1);
        }
-#endif
-       comedi_timed_1chan(dev,subdevice,chan,range,aref,freq,N_SAMPLES,data);
 
-       for(i=0;i<N_SAMPLES;i++){
-               printf("%g\n",data[i]);
+       if((n=read(comedi_fileno(dev),data,N_SAMPLES*sizeof(sampl_t)))<0){
+               perror("read");
+               exit(1);
        }
+       printf("number of samples read=%d\ndata[0]=%d\ndata[N-1]=%d\n",
+               n/sizeof(sampl_t),data[0],data[N_SAMPLES-1]);
 
        return 0;
 }