EPROM emulator

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I have a need for an EPROM emulator for a job, after which I don't expect the
need will arise again.  I ONLY need 2716 capability, not any other
size/capability.

Is anyone aware of any real cheap basic units out there?  Kits?

Anyone have one that they no longer need?

Re: EPROM emulator

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Google for NVRAM. 2k types are on the market for years already. Used a
Dallas DS1220 (now Maxim) at the time. If memory serves it was even pin
compatible with the 2716. SGS Thomson (STMicroelectronics) had a similar
device.

petrus bitbyter



Re: EPROM emulator



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You can probably BUY a 2716 programmer for less than the cost of an emulator.

Please tell more.

Graham




Re: EPROM emulator
On Fri, 15 May 2009 23:12:28 +0100, Eeyore

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I have EPROM programmers here.  That's not the problem.

The requirement is to be able to fast-cycle the contents of a few locations
under PC program control.  This is to identify by trial-and-error (normal
"analysis" yielded nothing) the required "checksums" for rows of data in a
target device whose processor code isn't accessible for reverse-engineering.

I could use either RAM or parallel EEPROM (2816 style) but was hoping to avoid
the design cycle of coming to grips with the to's and fro's of the shared memory
in an emulator and then building a solution.

Re: EPROM emulator
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memory
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so you don't need to emulate the whole 2716 just a few bytes of it,
can probably be done fairly cheaply with discrete logic.


Re: EPROM emulator

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the
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memory
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almost.  It is four bytes at each of 160 locations spaced regularly throughout
the 2K image, so it would be possible to achieve it with glue logic.  But a
shared memory approach (aka emulator) is my preferred approach.  I am trying to
avoid an extra design project to address the underlying issue.

Re: EPROM emulator
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moi,
google for DS1213C, DS1213D, DS1235YWL.
I have all of these, plus an extra C version that have been sitting here
for eons, and I will never use them now. Four in total.

Like petrus bitbyter, I used them to make my eproms writable.

I can't help you with specifics, as I got too old, and blind, so you
will have to research the data sheets and figure it out for yourself,
but you will be able to connect one of these up as a 2716, with a
read-write switch.

They are all greater than the pin count of a 2716, so you will need to
tie non used address lines either high, or low, and figure out the
read/write protect switching. But it will all be simple resistor pullups
or downs.

But it's all doable and cheap if you know what you are doing. You will
need to make up an adapter of some sort, to get down to the 24 pin count
of the 2716, if you are inserting it into an existing board.

I would hope that at least one of the four chips is still alive after 57
million years for you to give it a go, no guarantees there either.

All I need is for you to cover postage and a padded bag. Email me for
details.

Cheers Don...



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Don McKenzie

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