newbie building a scratch-built computer

[Dave McGuire]

On Aug 10, 2007, at 2:59 AM, Chuck Guzis wrote:
>>    Well I guess I define "obsolete" as "useless".  That seems to jibe
>> with the industry definition as well.
>
> So, 1701 EPROMs aren't obsolete? ;-)  I assume that some can be found
> that are still operable.

   Pick, pick, pick! ;)  I will try to be more clear about what I  
mean.  "Obsolete" means, to me, "no longer of any practical use".

>>    I've played with I2C FRAMs, but not byte-wide parts.  Are they
>> easy to program?
>
> Almost exactly like SRAM.  You write individual bytes, not the whole
> device during a write cycle.  Timing for write is about the same as
> that for read.  The 5V FM1808 (32Kx8) is a 70 nsec part.  While not
> blazingly fast by modern standards, it's good enough for most
> "vintage" designs.  Ramtron gives the number of read/write cycles as
> being in excess of a trillion.  Depending on your decoding logic for
> WE\, you could use the same part for RAM and ROM.  I've got a couple
> here and I like them very much.  28-pin DIP package.

   I'd love to get ahold of a few of those.  I'll see if I can tack a  
few into my next parts order.

            -Dave

-- 
Dave McGuire
Port Charlotte, FL
Farewell Ophelia, 9/22/1991 - 7/25/2007