Specifications
Comedi
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convert_arg value is interpreted as follows:
convert_arg == (CR_EDGE | 0) => rising edge
convert_arg == (CR_EDGE | CR_INVERT | 0) => falling edge
convert_arg == 0 => falling edge (backwards compatibility)
convert_arg == 1 => rising edge (backwards compatibility)
All entries in the channel list must use the same analogue reference.
If the analogue reference is not AREF_DIFF (not differential) each
pair of channel numbers (0 and 1, 2 and 3, etc.) must use the same
input range. The input ranges used in the sequence must be all
bipolar (ranges 0 to 3) or all unipolar (ranges 4 to 6). The channel
sequence must consist of 1 or more identical subsequences. Within the
subsequence, channels must be in ascending order with no repeated
channels. For example, the following sequences are valid: 0 1 2 3
(single valid subsequence), 0 2 3 5 0 2 3 5 (repeated valid
subsequence), 1 1 1 1 (repeated valid subsequence). The following
sequences are invalid: 0 3 2 1 (invalid subsequence), 0 2 3 5 0 2 3
(incompletely repeated subsequence). Some versions of the PCI230+ and
PCI260+ have a bug that requires a subsequence longer than one entry
long to include channel 0.
AO Subdevice:
The AO subdevice has 2 channels with 12-bit resolution.
The following output ranges are supported:
0 => [0, 10] V
1 => [-10, +10] V
AO Commands:
+=========+==============+===========+============+==========+
|start_src|scan_begin_src|convert_src|scan_end_src| stop_src |
+=========+==============+===========+============+==========+
|TRIG_INT | TRIG_TIMER(1)| TRIG_NOW | TRIG_COUNT |TRIG_NONE |
| | TRIG_EXT(2) | | |TRIG_COUNT|
| | TRIG_INT | | | |
+---------+--------------+-----------+------------+----------+
Note 1: If AI command and AO command are used simultaneously, only
one may have scan_begin_src == TRIG_TIMER.
Note 2: scan_begin_src == TRIG_EXT is only supported if the card is
configured as a PCI230+ and is only supported on later
versions of the card. As a card configured as a PCI230+ is
not guaranteed to support external triggering, please consider
this support to be a bonus. It uses the EXTTRIG/ EXTCONVCLK
input (PCI230+ pin 25). Triggering will be on the rising edge
unless the CR_INVERT flag is set in scan_begin_arg.
The channels in the channel sequence must be in ascending order with
no repeats. All entries in the channel sequence must use the same
output range.
DIO Subdevice:
The DIO subdevice is a 8255 chip providing 24 DIO channels. The DIO
channels are configurable as inputs or outputs in four groups:
Port A - channels 0 to 7