My first computer that I could really mess with assembler was a BBC micro. Here I want to design and built something much simpler than an 8-bit microprocessor, my nano processor. Mostly I expect it's best use will be as a warning to others.
Right now this site is just a place to collect my thoughts. Current tasks are:
- Transistors or relays (http://www.electronixandmore.com/projects/relaycomputertwo/index.html). Relays are more physical, but run too slow. The rest assumes transistors...
- I expect the majority of transistors to be in the registers and with a 4T memory cell that's about 512 transistors which is right on the edge. I'm not sure I can get the 4T working, if I can't then this project dies. This (http://3bitshiftregister.blogspot.co.uk) has effectively 5 transistors per bit but has capacitors which may severely limit the clock rate.
- Finalise the instruction set
- Finalise an emulator
- Write Forth for the emulator and go back and tweak instruction set if needs be
- Check that the registers work in transistors
- Build the lot in verilog and go back to tweak if needed
Come back in 2017!