I’ve changed my mind on microcode sequencing. Again. Ok, I know I would be fired if all this was for real, but I don’t like the sequencer design with ‘next’ field embedded in the microcode word anymore. The problem is with the ‘next’ field itself which I planned to be longer that 8 bits. This requires not ...
It’s been a long time since I last posted on this site or did anything related to the project. Way too long. My paying job has had me extremely busy lately. Add to this a long awaited apartment flip we had, sooner than expected due to our contractor’s change of schedules and you’ve got the story. I ...
Back from a 3-week long vacation in Cuba. Time to get back to work. As mentioned before, the machine will be a typical CISC with a wide microcode word, with little encoding. That means that bits from microcode ROM will be directly used as control signals. This is in contrast to a RISC-like approach, where ...
I mentioned in my last post that my intention is to design with a two-address instruction set. This means that my instructions will have zero, one or two operands. There is no important reason for this. I am familiar with 6502 (accumulator, one-address) and x86 instruction sets, and I am more used to the latter, ...
This site was set up to document my attempts to build a fully-featured, self-contained microcomputer using only basic logic elements (74-series TTL). The idea itself is nothing new and projects like this one are already out there (and completed – check my links page to see Bill Buzbee’s or Steve Chamberlin’s masterpieces which inspired me ...
