- From: Bernd Porr <Bernd.Porr_at_cn.stir.ac.uk>
- Date: Tue, 20 May 2003 18:45:41 +0100
Herman,
at least there is one driver which makes it clear: amplc_pci230.c
static void pci230_handle_ao(comedi_device *dev, comedi_subdevice *s) {
...
if(devpriv->ao_count == 0 && devpriv->ao_stop == 0) {
/* End of DAC. */
async->events |= COMEDI_CB_EOA;
pci230_ao_cancel(dev, s);
}
else {
/* More samples required, tell Comedi to block. */
async->events |= COMEDI_CB_BLOCK;
I got inspired by this driver. :-)
/Bernd
Herman Bruyninckx wrote:
> On Tue, 20 May 2003, Bernd Porr wrote:
>
>
>>it's essential for the function comedi_buf_get for asynchronous analog
>>out. When the interrupt handler needs more data from the user-space it
>>signals this with COMEDI_CB_BLOCK.
>
>
> How do you know this? :-) I don't find any really definite explanation
> in the Comedi code, although many drivers use it...
>
> Herman
>
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Received on 2003-05-20Z16:45:41