- From: David Schleef <ds_at_schleef.org>
- Date: Thu, 30 Jan 2003 13:15:13 -0800
On Mon, Jan 27, 2003 at 08:45:10AM -0800, Tim wrote: > I am using a Measurement Computing PCI-DAS1200jr. I need to sample 4 > AtoD channels and 2 DIO lines at a specified rate. > > What I'm wondering is whether this is possible with comedi? I > understand that I can sample the AtoD, but is it possible to also read > the DIO lines each time the AtoD scan is complete? Perhaps with a user > defined IRQ handler, or somehow a call during the bottom half of the > interrupt handler? I don't know of any *boards* that do this correctly, that is, in hardware. To simulate this capability, you'd need to use Comedi with RTAI. One way is to use an AI command with a real-time callback that measures your digital inputs. The other way is to use a periodic task to measure both the analog input and digital input at each period. The comedi_rt_timer driver uses the latter method to simulate an onboard timer on devices that don't have one natively. It only works for one subdevice, but could reasonably be extended. dave...
Received on 2003-01-30Z21:15:13