Re: 74S288 Prom compatibility question

That explains a lot, Rodger, thanks. Probably best bet is to find
someone with a Unisite who would burn my logic for me.

 jS

Rodger Boots wrote:
> Not sure, will check. Would certainly think a DataIO 29 would. Also,
> if buying blank parts from a vendor like DigiKey or Newark they might
> program them for you (would have to ask).
>
> I'll check.
>
> One other difference between PROMs and EPROMs are that EPROMs are
> programmed a byte at a time while PROMs are programmed bit by bit.
> Most PROMs are programmed by melting fuses. Newer parts may program
> like EPROMs, but the old ones are fuses.
>
>
> js@cimmeri.com wrote:
>>
>> Thanks for your reply, Rodger. What you're saying, however
>> unfortunate, makes sense. So they're like PALs rather than like EPROMS.
>>
>> Are you aware of any burner that handles the TI proms?
>>
>> jS
>>
>> Rodger Boots wrote:
>>> 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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>>>
>>
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Received on Tue Jan 26 18:30:23 2010