Intel's web site still has some information abotu the 8255:

http://www.intel.com/design/periphrl/overview/7190.HTM
http://www.intel.com/design/periphrl/technote/7012.HTM
http://www.intel.com/design/periphrl/datashts/index.htm

I have used this chip a LOT in the past, and still have a 1978 edition of
the Intel Peripheral Design Handbook...  what would you like to know?  It
provides three independent 8-bit I/O ports.  Each can be set for input or
output, and PORT C can be split 4 bits in and 4 out.  CPU interface is
pretty standard, 8 bit data bus, !CS, !WR, !RD, and A0/A1 to select port
or config register.  The last link above will score a complete data sheet
for you from 1995.

It's really a pretty old chip, and a lot of what you'd want to do can be
done with a 16F877.  The '55 had a pretty low drive capacity, nothing near
the PIC's.  Still, it was really the standard for many years, used in
numerous PC I/O cards, data acquisition cards, etc.  I think they're
probably still made by companies other than Intel and probably still used
in some products.

Dale
--
"Curiosity is the very basis of education and if you tell me that
curiosity killed the cat, I say only the cat died nobly."
          - Arnold Edinborough


On Thu, 25 Jul 2002, Richard Mellina wrote:

>         Anyone know of any good websites concerning the 8255-PPI from Intel? I need
> to know how to interface it to a parallel port for a home automation
> project. Any tutorials? I haven't had much time to look around yet. Anything
> that you may think is helpful. Thanks!
>
> --
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>
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