Design of homebuilt TTL PC

Peter F.  I always think about your work ! 😍Is it full in TTL logic ? How is the simulator going ? I dream with that and with relay computers. As I told you my first computer was a 4 bit ttl I made at 12-13 years. With that 74181Alu, I still have my TTL collection from that time(not LS, "real heavyweight TTL" they are terrible power hungry!) . Regrettably the minicomputer with 4x4 rows of leds...was scrapped.

Bill V. My project was similar to yours. I used three 74181's and a chip, I forget which, that tied them together. It was all TTL, mostly open collector as that was easier to wire-or together. I made it 12 bits as that was enough for addressing the 2102 memory chips and giving me lots of options for instructions. Four of the 12 bits in the instruction register went right to the 74181s so I had access to all commands.

I'm sorry now I scrapped the original slit-and-wrap circuit boards but I still have all the TTL IC's somewhere.

I hope to wire-wrap a replica of the original and eventually build a new and improved version with better TTL - like HCT or maybe CMOS.

The emulator is advancing a little every day. It's a wonderful mental exercise working with the emulator and thinking of the tradeoffs between actual hard coded in TTL instructions and other new and enhanced instructions in software. The software is so easy but it won't eventually run in the upcoming computer.

Fwd: Posting to blog from email

Second try - perhaps I didn't save the configuration fast enough earlier.


Yet another way to make all the tools work together. This is a step.
A small step. A small step in what is hopefully the right direction.

Stay tuned...