I have some EPROMs, from Russia

What is our fixation with chips produced by the Soviet union by the help of industrial espionage? Or is it just me that likes to collect these?

Today, I’ve received another consignment of them:

This is a set of 4 U552C’s – the Soviet version of the Intel 1702A which I recently built a programmer for.

Before I get started, there is a familiar problem which is that the pin spacing of these chips is a metric 2.5mm, not the usual imperial 0.1″. Engineers from the USSR apparently felt the need to correct the oddities of the imperial past. Sockets with this pin spacing are more difficult to come by than the chips that plug into them, but today I’ve got some, so I’ve built a little adapter:

Just for a laugh – I though I’d try program them using the x86 build of that programmer on another Soviet chip: the K1810VM86 – a clone of Intel’s 5MHz 8086 processor.

The test setup – an un-holy mix of components from either side of the iron curtain.

On the first run I nearly burnt out an EPROM because I’d forgotten that the x86 HvEprom build is hard coded for a 10MHz CPU, whereas the K1810VM86 only ran at 5MHz, so I had to go back and re-do all of the timings.

They all programmed and verified no problem.

The last test is to pop them in my 1702A reader, and we can see that the ASCII letter ‘K’ is in the first position as expected.

Posted in Vintage microcontrollers

4 thoughts on “I have some EPROMs, from Russia

      1. The GDR wasn’t part of the Soviet Union, though, so calling them the “Soviet version” isn’t very accurate.

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