comedi_dio_bitfield2 — read/write multiple digital channels
#include <comedilib.h>
int comedi_dio_bitfield2( | comedi_t * device, |
| unsigned int subdevice, | |
| unsigned int write_mask, | |
| unsigned int * bits, | |
unsigned int base_channel); |
The function comedi_dio_bitfield2
allows multiple channels to
be read or written together on a digital input, output,
or configurable digital I/O device.
The parameter write_mask
and the value pointed to by bits
are interpreted as bit fields, with the least significant bit
representing channel base_channel.
For each bit in write_mask that is
set to 1, the corresponding bit in
*
is written to the digital
output channel. After writing all the output channels, each
channel is read, and the result placed in the approprate bits in
bits*.
The result of reading an output channel is the last value written to the
output channel.
bits
All the channels might not be read or written at the exact same time.
For example, the driver may need to sequentially write to
several registers in order to set all the digital channels specified
by the write_mask
and base_channel parameters.