31 Jul
2004
31 Jul
'04
2:02 a.m.
At 05:26 PM 7/30/04 -0700, you wrote:
For one thing the parts used in the HP 1000 are 25 to 35 nS parts. Also
the enable and other control lines are very different so you'd need a fair
amount of glue chips and probably a buffer.
Joe
OK. I was
thinking about the microcode ROMs in an HP9810 (somethign that
_I_ am working on, and those are most certainly 'hit' as soon as INIT is
deaseserted and the microocde program counter starts to change. I prefer
to think of general-purpose solutions (i.e. somethign that will replace
every 256*4 ROM), rather than soemthing that works only in specific
machines under specific circumstances.
I must not be getting it, somehow.
Why can't you just use a 45ns or 55ns 27c256 or 27c512 and swizzle the
pinout? These are around $3 per chip, and seem to meet the requirements.
Vince