The purpose is to understand how the PROM 82S129 is used in this design.

Before the advent of programmable logic, PROMs were often used in lieu of discrete logic.

I expect that PROM was used to decode particular ISA bus addresses and perhaps other ISA bus signals and react accordingly.

In other words, certain locations in the PROM would be programmed to react so that the output pins would be in the right state for a particular address.

That particular PROM has 8 address inputs and four outputs.

Here is an example of how you would use a PROM as logic. Let's say you wanted to make a 3 input NAND gate. For discuss purposes we will use the upper three bits of the address lines as inputs and one of the 8 data output bits as the NAND output. The programming of the PROM would be as such:

All PROM locations from 00000000 to 00011111 would have a data output pattern of 1111 (assuming the default output state of the PROM is a '1').

For all PROM locations from 11100000 to 1111111 would have a data output of 0111 (assuming the default output state of the PROM is a '1').

With this programming, any time the upper three address bits are a '1', then Bit 0 of the data output bits will be a '0', which is a 3 input NAND function.

As you can imagine, figuring out which addresses should have particular data output patterns can get quite complicated when you use a PROM as a replacement for random logic.

Another issue with using PROMs for logic replacement is that their outputs are glitchy, meaning, when one input pin changes you can have momentary glitches on any or all of the outputs while the internal address decoder of the PROM settles. Because of this behavior, PROMs were often used in a synchronous fashion to avoid the glitches. Programmable Logic does not have this issue which is why it is so popular.

Here is the diagram of the card (in progress)

 

 

The content of the bipolar PROM 82S129 "FAT03011D" is given here : 82S129.BIN

dump of the bipolar PROM 82S129.TXT

Adaptateur parallèle série DONATEC 286-12 Guide de l'utilisateur (PDF-18 pages - 443 Kb)

Datasheet of the PROM 82S129 1K-Bit TTL Bipolar PROM (256 x 4)

Datasheet of the UM82C11 PRINTER ADAPTER INTERFACE (PAI)

Datasheet of the UART NS16C450N UNIVERSAL ASYNCHRONOUS RECEIVER/TRANSMITTER (UART),

Notice de la carte mère DONATEC 286 (1.48Mb - 27 pages) This brochure details the connexions of the ISA Bus (See page 12 to 19)

Notice de la carte RS-232/IMPRIMANTE pour PC/AT DONATEC Réf. IF201 DONATEC (906Kb - 7 pages)

KMA-202F-12R PC-AT286 Motherboard User's Manual (PDF - 920Kb- 50 pages)

 

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If you look forward for other information about this DONATEC ISA interface card, do not hesitate to contact me by e-mail at: matthieu.benoit@free.fr .
Important Notice: Also if you have any data about this kind of interface, do not hesitate to contribute to this page.