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 cooresponding bit in *bits
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.
All the channels may not be read or written at the exact same time.
For example, the driver may need to sequentially write to
several ports in order to set all the digital channels specified
by the write_mask
.