cont

Makefile

+x: test_write
+	./test_write
+
+test_write : test_write.c
+	gcc -o $@ $< -lcomedi
+
 all: dist/mycomedi.jar
 	java -cp $< -Djava.library.path=src/main/jni com.github.lindenb.mycomedi.ComediJFX
 

test_write.c

+/*
+ * Tutorial example #2
+ * Part of Comedilib
+ *
+ * Copyright (c) 1999,2000 David A. Schleef <ds@schleef.org>
+ * Copyright (c) 2008 Frank Mori Hess <fmhess@users.sourceforge.net>
+ *
+ * This file may be freely modified, distributed, and combined with
+ * other software, as long as proper attribution is given in the
+ * source code.
+ */
+
+#include <stdio.h>		/* for printf() */
+#include <stdlib.h>
+#include <comedilib.h>
+#include <ctype.h>
+#include <math.h>
+
+#define DEBUG(f_, ...) do { fprintf(stderr,"[DEBUG:%d]\"",__LINE__);fprintf(stderr,(f_), __VA_ARGS__);fprintf(stderr,"\"\n");} while(0);
+
+int subdev = 1;			/* change this to your input subdevice */
+int chan = 0;			/* change this to your channel */
+int range = 0;			/* more on this later */
+int aref = AREF_GROUND;		/* more on this later */
+const char filename[] = "/dev/comedi0";
+
+int main(int argc, char *argv[])
+{
+	comedi_t *device;
+	;
+	double physical_value;
+	int retval;
+	comedi_range *range_info;
+	lsampl_t maxdata;
+
+	device = comedi_open(filename);
+	if (device == NULL) {
+		comedi_perror(filename);
+		return 1;
+	}
+	range_info = comedi_get_range(device, subdev, chan, range);
+	maxdata = comedi_get_maxdata(device, subdev, chan);
+	comedi_set_global_oor_behavior(COMEDI_OOR_NAN);
+	double userdata=10;
+	double sign=1;
+	double shift=0.001;
+	double max=10;
+	for(;;)
+		{
+		//DEBUG("userdata = %g",userdata);
+		lsampl_t data =  comedi_from_phys(userdata, range_info, maxdata);
+		//DEBUG("data = %d",data);
+		retval = comedi_data_write(device, subdev, chan, range, aref,
+					  data);
+		if (retval < 0) {
+			comedi_perror(filename);
+			return 1;
+			}
+
+		userdata +=(sign*shift);
+		if(userdata > max) {
+			userdata= max;
+			sign=-sign;
+			}
+		else if(userdata < -max){
+			userdata= -max;
+			sign=-sign;
+			}
+		}
+	return 0;
+}
+