🚀 go-pugleaf

The 8255 is still an excellent PIA in many respects. However there
is one very important point which is not obvious from the data
sheet and can rule out use of the part for certain applications.

I can't remember the exact details but basically you cannot turn
an I/O pin from input to output (or vice versa) on the fly
without resetting the whole port and causing all the pins to
glitch. I had this problem while interfacing the 8255 to an LCD,
trying to turn a single bit around to read the LCD "BUSY" completely
stuffed things up. There was no way around this problem for my
application and I had to use a different part.

If you think this may be a problem for you, I advise a _VERY
CAREFUL_ reading of the data sheet.

Regards
Jim

       If it wasn't for blinds it'd be curtains for all of us
     Jim Francis - Melbourne - Australia - <j...@webrider.net.au>