Re: Need help with cmd.c

Hello Daniel,

On Tue, Nov 12, 2002 at 10:46:59PM +0100, Daniel Koch wrote:

> comedi_config /dev/comedi0 pc104-das16/jr16 0x220,,3,10,,,,,100 
> - --read-buffersize 4096
> 
> I`m not sure about the 100, is it freq/1000 ?

The parameter #8 (when starting with #0) is just boolean, 0 or 1. The
timing for the timer interrupt is calculated automatically by das16.c

I think I have a slightly modified version, which calculates the
timing as follow:


#define MINIMUM_TIMER_PERIOD	(HZ / 15)	// 0.6s
#define MAXIMUM_TIMER_PERIOD	(HZ / 2)	// half a second

...

// utility function to suggest timer period in jiffies in timer mode
static unsigned int das16_suggest_timer_period(comedi_device *dev, comedi_cmd cmd)
{
	unsigned int period = 0;

	if (cmd.convert_src == TRIG_TIMER)
	{
		// fill up DMA no more than 50% for fastest DAC
		period = (HZ * (unsigned long)cmd.convert_arg) / 100000;
	}

	if (period < MINIMUM_TIMER_PERIOD)
		period = MINIMUM_TIMER_PERIOD;
	else if (period > MAXIMUM_TIMER_PERIOD)
		period = MAXIMUM_TIMER_PERIOD;

	DEBUG_PRINT("period = %u\n", period);

	return period;
}


Your mileage might vary.

Roman

-- 
Roman Fietze                                fietze_at_s.netic.de
My public key is on   http://www.s.netic.de/fietze/index.html