I've wanted to build a home-brew computer since I was a kid but I wasn't really able to since I knew nothing about how to make them... until now. I taught myself a lot during the time that I've been in quarantine so I could finally design and build my "dream" minicomputer, for both my own enjoyment and the upcoming senior project showcase at my school.
The ATLAS CPU-8 features an 8-bit data bus and a 16-bit address bus. Early in the design phase I found that having a modified Harvard architecture just "felt right", so I went with it. I also decided to employ the use of microcode, as I wanted experience with writing microcode.
Once the Logisim implementation is complete, I will build it in real life with TTL chips. For I/O, I am planning on using a serial terminal. It will also be outfitted with plenty of blinkenlights :-)
Hello, this is the first log entry for the ATLAS CPU-8. I've been working on it for the past three weeks, and what I have so far is a somewhat functional Logisim implementation. As of the time of posting, I have written and tested 22 working operations (0 - 21). Once I'm done with the arithmetic operations, I'll move onto the program memory read/write ones and finally the jumps.
I am still thinking about how I will approach serial addressing, although I'm probably going to make it memory-mapped. I've also had thoughts about revising the data bus design, although I feel that it would be more trouble than it's worth.