On Feb 5, 2010, at 6:51 PM, Chuck Guzis wrote:
I am trying to
think of where the 8255 was used. OK, on the 5150 and
5160 motherboard to handle the keyboard interface and DIP switches,
where glitches don't matter. What other major uses did it have? Very
frw of my classic computers use one.
Quite a few 8-bit x80 micros used them them for various purposes
(yes, even Z80 systems); The 5150 BIOS refers to an 8255 in the
printer code, even though they didn't use one. A FAX machine I
looked at not long ago used one. I've got a 90's PCI-bus data
aquisition card that uses 3 of them.
I wonder if the 5150 was originally designed with an 8255?
But there really is no good reason to use an 8255, a
Z80 PIO, a 6820
or even a 6522 in a new design today, other than for nostalgia's
sake.
Well if you really want to think that way, there's really no good
reason to use ANY digital component (save for perhaps the very
highest-clocked microprocessors) other than an FPGA in a new design
today.
-Dave
--
Dave McGuire
Port Charlotte, FL