I agree, mostly, with what you've said here, Tony. The easy fix, in many
cases will be to program the code into several larger but readily available
and easily programmed parts, then wire an adapter from the target board's
socket to the physical EPROM on the board on which the EPROM resides, with a
pair of appropriately sized IDC ribbon cable headers crimped on the ends of
the cable. That should work, even if you have to hang the adapter board
from a hanger in the rack. Packaging problems are what the REAL engineers
work hardest at, while the youngsters conjure up the fancy circuits. This
is mostly a packaging problem. The higher speeds of today's common and
cheap parts will compensate for the few nanoseconds lost in cables, even if
some form of termination has to be introduced.
Dick
-----Original Message-----
From: Tony Duell <ard_at_p850ug1.demon.co.uk>
To: Discussion re-collecting of classic computers
<classiccmp_at_u.washington.edu>
Date: Monday, November 01, 1999 1:50 PM
Subject: Re: EPROM issues, who can burn?
>> Thats simple, if emulation will make you happy, why stop at the eproms,
>> just run one of the emulators for the whole system on your PC. My goal is
>
>Oh, come on, there's a heck of a difference between replacing an EPROM
>with a more modern (and larger) one containing the same code and running
>an emulator for the entire machine on a PC. Well, certainly to a hardware
>hacker there's a difference :-)
>
>> to get old systems running at a low cost, and I think that means original
>> or functional equivalent parts.
>
>Ah, but the modern/larger EPROM _is_ a functional equivalent part.
>
>Yes, obviously you use the original type of EPROM if at all possible. But
>if you _can't_ get the part, then it makes a lot of sense to use (say) a
>2764 with the same code in it.
>
>A secondary issue occurs when the original part was a mask-programmed
>ROM. They can fail as well... Or you might want to make some changes to
>the code. In that case you virtually have to use an EPROM and make an
>adapter.
>
>>
>>
>>
>
>-tony
>
Received on Mon Nov 01 1999 - 15:15:45 GMT