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A project log for AMD 2900 Chipset Research

Exploring the 2900 family bit slice chip set.

Rey MortaRey Morta 06/01/2020 at 05:023 Comments

I got side tracked for a bit. I have a 16 bit alu wired up. Its not the most photogentic project. To simplify working I made a stack of PCB board with AM2901 chips. The common signals travel vertically via stacking headers. This still needs fully tested. 

I am still hung up on how I will setup the Microcode seqencer. I have in my possession all three options for AM2909, AM2910 and AM2910 chips. The current issue I am running into is the microcode map (ROM) for using 8 bit instruction requires memmory with 8 address lines and 12 data lines. 

In other news I found a write up via Dangerous Prototype, Ken Shirriff did a post on the internal silicon of the AM2901.  Found here: http://www.righto.com/2020/04/inside-am2901-amds-1970s-bit-slice.html

Discussions

Philip wrote 06/01/2020 at 08:18 point

Hi Rey.  I have a bit (pun intended) of experience in this area. I posted some pictures via twitter:  https://twitter.com/PhilipFreidin/status/1257829970576994307  and the link in the second tweet leads to some detailed system diagrams.  I was the product planning manager (responsible for defining how the chips would work, defining new products) for microcoded products at AMD during the last 4 years that the AM2900, 293xx, and 295xx families were still being promoted. Prior to that I was an application engineer for several companies including AMD, and helped engineers in designing and using AM29xx products. If you want to chat, skype or zoom are an option. I hope you have a lot of fun with your project and learn a lot along the way.

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Rey Morta wrote 06/02/2020 at 03:36 point

Evening, 

Kind of awestruck between yourself and a Peabody1929. Yes I would like to talk to you some time. I just as intersted in work with AMDs products as the Microcomputer Club Of Melbourne. We'll have to arrange that.  

The Munchkin Project. That is beautiful. When I started looking at the AM2901 I had similar thoughts of how far the chipset could be taken. Two of the big ones were the idea of a dual mode system. It would flip between running as a 6502 ISA or RCA1802 ISA. The other would be to attempt a 1024 bit ALU. 

Half the idea of doing this hackaday project is to try to gather more interest into this chip set. The other half was to fight against crazy ideas that chip set creates. Just slowing done and looking at the parts piece by piece.  

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Ken Yap wrote 06/01/2020 at 05:11 point

Thanks that was a fascinating read as usual from Ken Shirriff. I know of such chips only from databooks. 

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