comedi_command - analog input - only runs once

• From: Tim Lee <timothy1ee_at_yahoo.com>
• Date: Mon, 21 Jun 2004 23:21:27 -0700 (PDT)

I am trying to run a slightly modified version of the
it.c example, which I have copied below.  In another
modified version (not included), I read data from the
buffer, and it seemed to be correct data.  However, in
both cases, the callback function is only called once.
 There are no error messages in the kernel log.  The
kernel log is shown below.  Any idea why it doesn't
continue to run?  Thanks,

Tim Lee

System details:
kernel: linux-2.4.24-adeos
RTAI: v3.0r2
comedi: a CVS snapshot soon after 0.7.68

Jun 21 23:10:27 Chivo kernel: Comedi real-time example
#1
Jun 21 23:10:27 Chivo kernel: Tapping: comedi_lock: 0
Jun 21 23:10:27 Chivo kernel: command test returned 0
Jun 21 23:10:27 Chivo kernel: command test returned 0
Jun 21 23:10:27 Chivo kernel: command returned 0
Jun 21 23:10:28 Chivo kernel: who's yer daddy? 0

#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/comedi.h>
#include <linux/comedilib.h>
#include <rtai.h>

comedi_t * dev=NULL;
int subd=0;

int do_cmd(void)
{
	int ret;

	comedi_cmd cmd;
	unsigned int chanlist[1];

	cmd.subdev = subd;
	cmd.flags = TRIG_RT | TRIG_WAKE_EOS;

	cmd.start_src = TRIG_NOW;
	cmd.start_arg = 0;

	cmd.scan_begin_src = TRIG_TIMER;
	cmd.scan_begin_arg = 1000000000;

	cmd.convert_src = TRIG_TIMER;
	cmd.convert_arg = 10000;

	cmd.scan_end_src = TRIG_COUNT;
	cmd.scan_end_arg = 1;

	cmd.stop_src = TRIG_NONE;
	cmd.stop_arg = 0;

	cmd.chanlist = chanlist;
	cmd.chanlist_len = 1;

	chanlist[0] = CR_PACK(0,0,0);

	ret = comedi_command_test(dev,&cmd);
	printk("command test returned %d\n",ret);

	cmd.chanlist = chanlist;
	cmd.chanlist_len = 1;

	ret = comedi_command_test(dev,&cmd);
	printk("command test returned %d\n",ret);
	if(ret)return ret;

	cmd.chanlist = chanlist;
	cmd.chanlist_len = 1;
	cmd.data = NULL;
	cmd.data_len = 0;
	ret = comedi_command(dev,&cmd);
	printk("command returned %d\n",ret);

	return ret;
}

static int counter = 0;

int callback(unsigned int i,void *arg)
{
	rt_printk("who's yer daddy? %d\n",counter);
	counter++;

	return 0;
}

int init_module(void)
{
	int ret;
	char dev_name[] = "/dev/comedi0";

	printk("Comedi real-time example #1\n");

	dev = comedi_open(dev_name);
        if (dev == NULL)
	{
           rt_printk("Tapping: Failed opening DAQ
card.\n");
	   return(1);
	}
	
	ret = comedi_lock(dev, subd);
	rt_printk("Tapping: comedi_lock: %d\n", ret);


comedi_register_callback(dev,subd,COMEDI_CB_EOS,callback,NULL);

	do_cmd();

	return 0;
}

void cleanup_module(void)
{
	int ret;

	ret = comedi_cancel(dev,subd);
	printk("comedi_cancel: %d\n",ret);
	
	ret = comedi_unlock(dev, subd);
	printk("comedi_unlock: %d\n",ret);
	comedi_close(dev);
	printk("comedi_close:\n");
}



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Received on 2004-06-22Z05:21:27