Glitches using 8255?

I am using a National Instruments PCI-6503 for digital I/O, this is a
fairly simple PCI based 8255 card.  I am curious about the possibility of
"glitches" using the digital output.  I have port A (channels 0-7)  
configured for input and the other 16 channels configured for output.

I use one half of port C (4 lines) to control an address decoder.  I am
curious if, using comedi_dio_bitfield, it is possible to have a "glitch"  
in the output such that the lines are in a state that is neither "before"  
nor "after".  In other words, can I count on this function (and the 8255
chip) to make all the requested changes (within a single port)
simultaneously?  Or do I need to disable my address decoder, put the new
address on the port and then re-enable the decoder?  I know that disabling
the address decoder would solve the problem for sure, but I do not want to
do that because I do not want to use another channel on the I/O board.

Received on 2003-06-15Z19:37:42