Re: comedi_rt_timer

On 23/02/05 08:56, Emmanuel PACAUD wrote:
> In comedi_rt_timer driver, start src must be TRIG_INT for analog output,
> and TRIG_NOW for all other emulated subdevices.
> 
> And I don't understand why...
> 
> Could someone with more knowledge than me about comedi explain such a
> limitation ?

Using TRIG_INT allows you to write data to the device before starting 
the acquisition.  If TRIG_NOW was used, there might not be any data 
available for the first scan or the first conversion, in which case an 
underrun error would be reported.

The Comedilib documentation mentions TRIG_FOLLOW as a possible start_src 
for an output subdevice.  This says that the acquisition should start 
when data is written to the buffer.  However, it's not supported yet :-(

-- 
-=( Ian Abbott _at_ MEV Ltd.    E-mail: <abbotti_at_mev.co.uk>        )=-
-=( Tel: +44 (0)161 477 1898   FAX: +44 (0)161 718 3587         )=-

Received on 2005-02-23Z12:11:45