Programming Bipolar PROMs (Tom Hunter)

mark at mark at
Mon Sep 27 16:30:17 CDT 2021

From: Tom Hunter <ccth6600 at>
Subject: Programming Bipolar PROMs

> The part is an Intersil IM5600CP, but these were also made by others, for
> example Signetics and Philips made the 82S23 and TI and NTE made the 
> faster
> SN74S188N. Some vendors still sell these parts and there are even a few on
> Ebay.
> How do I program these PROMs? I found one somewhat obscure description of
> the algorithm in the NTE datasheet, but I suspect that each manufacturer
> had (somewhat) different algorithms.

I built a project using Russian clones of the 74188, and ended up building a 
programmer for them.  The programming process is slow (over a minute to 
program 32 bytes), draws quite a bit of power (the chip is uncomfortably 
warm afterwards), and it took a while to work out the programming algorithm. 
Also, as Tom Hunter mentioned, the programming process isn't perfect - about 
5% don't program correctly; I don't know if this is my algorithm or the fact 
that the clones aren't so good.  However, once programmed, they seem to work 
just fine.

I bought the Russian devices off eBay for cheap - I think they were about 
$0.20 apiece, so I got a hundred of them, which I've been slowly nibbling 
away at as my little product sells.  I still have several dozen left; if 
you'd like you could send me the hex file (or listing - it's only 32 bytes, 
which I could type in), and I could program a couple for you.

I'm not sure I could recommend building your own programmer.  It's obviously 
possible, and there are hand-operated versions floating around on the 
internet (really hand-operated: set a rotary switch for the bit and five 
address switches, turn on the power, and push a button for 1-1/2 seconds; 
repeat for every "1" bit in the PROM), but you'd need more than just the 
Arduino.  You need eight high-side drivers that will handle an amp apiece, 
plus another driver to switch the power supply voltage between 5 and 13.5 
volts, as well as writing a program to implement the algorithm.  (actually, 
it's slow enough that you could get by using relays for all the higher 
voltage switching.)

I don't believe that any modern programmer handles these - if the Data I/O 
does, then that's probably your only option.
Mark Moulding

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