Re: 74S288 Prom compatibility question

Unlike EPROMs, PROMs program differently from manufacturer to
manufacturer. From some manufacturers a blank part will be all zeros
and bits are programmed to ones. Other manufacturers will be the
opposite. And some Cypress parts will come up in random states when
blank and are forced to either ones or zeros as needed. Add to that
different timing and different voltages for programming and you have a
real mess.

Typically, just about everyone can handle National parts, support for
other brands vary.

js@cimmeri.com wrote:
>
> Hi folks. Trying to create a backup copy of a game board's National
> Semi DM74S288N 32x8 bit prom into what I believe is the equivalent
> chip, a TI SN74S88N. Yet, my Data I/O 2900 and Optima burners --
> both of which only list the Nat Semi chip -- can't seem to program the
> TI prom. They can read it, blank checks ok, but errs on burn -- all
> bits remain zeros.
>
> Anyone run into this problem before? Are the NS and TI chips not
> identical?
>
> Thanks for any advice.
>
> John Singleton
> Rockville, MD
>
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Received on Sun Jan 24 23:02:48 2010