NI6534 - writing data with external Trigger

Hi,

I am new to data acquisition with Comedi. I am using comedilib 0.7.21
and comedi 0.7.67. Installation and simple digital I/O works fine with
the NI6534.
What I want to do is to supply an external clock and use the comedi
comands to write data to a channel on every rising edge of the external
clock. Using the info program shows, that the driver supports commands
and external Trigger:

overall info:
  version code: 0x010000
  driver name: ni_pcidio
  board name: pci-6534
  number of subdevices: 1
subdevice 0:
  type: 5 (digital I/O)
  number of channels: 32
  max data value: 1
  ranges:
    all chans: [0,5]
  command:
    start: now|int
    scan_begin: timer|ext
    convert: now
    scan_end: count
    stop: count
  command fast 1chan:
    start: now 0
    scan_begin: timer 50
    convert: now 0
    scan_end: count 1
    stop: count 2


But comedi_get_write_subdevice() returns -1, so no streaming output is
supported and I can't write my data to the device.  Streaming input on
the other hand is supported.
Is the write function just not implemented jet? Or is this mode not
supported by the NI 6534? Are there other ways I can get my data into
the fifos on the card? (The command structure contains a data-pointer,
but it is only applicable when using the kcomedilib interface, not from
userspace).

Thanks,
Harry

Received on 2004-02-17Z13:31:03