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Looking for eproms.


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I'm looking for Green Board eproms.

The one currently installed has the following 34 lines printed on it.




PGM 12.5V

I search ebay and I don't get an exact match but a lot of options.


Are all of these the same thing?

Also, the board has jumper instructions for other chips - 27512, 27256 and 2764/27128.

Are these other chip types specific to applications?

What I mean is, can I burn 8k images to a 512? Or should I stick with What I need according to the program size?
If I want to burn TurboForth for instance, the original chip had it on there, would going to a different sized supported chip cause issues?

I ask about the different chips because it's cheaper to buy them in bulk and I'd rather get a larger chip if its more versatile (backwards compatible).

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The important line on the chip is "M27128A-2F1". That's an ST part, one of the larger EPROM manufacturers. Presumably any 27128 parts would work fine as long as they are fast enough (and these are 200 nanosecond parts), so if you wanted 16K EPROMs, I'd just search for "27128 EPROM" on eBay.


I can't answer the question about using larger EPROMs for smaller images as it pertains to the TI, since I don't have experience there. But I do this all the time with non-bankswitched games on the 2600. For instance, using 27256 parts for 4K games, because the 32K EPROMs are considerably more common these days than 2732 4K EPROMs (and they program much faster!).



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For 8K ROM images, you want to use a 2764 or a 27C64 chip (8Kx8, sometimes identified as a 64K chip).

For 16K ROM images, you want to use a 27128 or a 27C128 chip (16Kx8, sometimes identified as a 128K chip).

For 32K ROM images, you want to use a 27256 or a 27C256 chip (32Kx8, sometimes identified as a 256K chip).

For 64K ROM images, you want to use a 27512 or a 27C512 chip (64Kx8, sometimes identified as a 512K chip).

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