made BUF_LEN larger, so boards with huge ao fifos (ni 67xx)

don't underrun when starting up.

diff --git a/demo/ao_waveform.c b/demo/ao_waveform.c
index 9a869e83a316c6fc37526085ba98b37f32e0f033..a37eaa9ad8d3a73f6ed9b0f1f5c7f9058e5e55d7 100644 (file)
--- a/demo/ao_waveform.c
+++ b/demo/ao_waveform.c
@@ -68,7 +68,7 @@ double offset                 = 2048;
 /* This is the size of chunks we deal with when creating and
    outputting data.  This *could* be 1, but that would be
    inefficient */
-#define BUF_LEN                8192    
+#define BUF_LEN 0x8000
 
 int subdevice;
 int external_trigger_number = 0;
@@ -158,9 +158,6 @@ int main(int argc, char *argv[])
 
        dds_init();
 
-       dds_output(data,BUF_LEN);
-       dds_output(data,BUF_LEN);
-
        dump_cmd(stdout,&cmd);
 
        err = comedi_command_test(dev, &cmd);
@@ -180,13 +177,18 @@ int main(int argc, char *argv[])
                exit(1);
        }
 
-       m=write(comedi_fileno(dev),data,BUF_LEN*sizeof(sampl_t));
-       if(m<0){
-               perror("write");
-               exit(1);
+       dds_output(data,BUF_LEN);
+       n=BUF_LEN*sizeof(sampl_t);
+       while(n>0){
+               m=write(comedi_fileno(dev),(void *)data+(BUF_LEN*sizeof(sampl_t)-n),n);
+               if(m<0){
+                       perror("write");
+                       exit(0);
+               }
+               printf("m=%d\n",m);
+               n-=m;
        }
-       printf("m=%d\n",m);
-       
+
        ret = comedi_internal_trigger(dev, subdevice, 0);
        if(ret<0){
                perror("comedi_internal_trigger\n");