27256 vs 27512

[Ludis Langens]

Roger Heflin  <rah at horizon.hit.net> wrote:
> I don't know which it is.  I read it out as a 27256.  I don't know which
> one it really is.  There weren't any obvious numbers.  It is a 28 pin dip
> in a GM calpack.

Check the numbers on the 28 pin DIP EPROM:

  "16069300" or "69300" or "6 9300" == 27128
  "16045915" or "45915" or "4 5915" == 27256
  something else == probably a 27512

Note:  I have found some 27128 applications to use an EPROM marked with
the GM 16069300 number but also marked as 27C256s.  In a PROM reader,
they respond as if they really are '256s.  These are probably '256 chips
with a defect in the lower half of the array.  If a '256 is plugged into
a socket meant for a '128, only the upper half will be accessed.  Hence,
they can be used as '128's, but have to be programmed as '256's.

-- 
Ludis Langens                               ludis (at) cruzers (dot) com
Mac, Fiero, & engine controller goodies:  http://www.cruzers.com/~ludis/