16-bit Serial Homebrew CPU (jiristepanovsky.cz)
from tedu to tech on 21 Aug 2023 17:49
https://azorius.net/g/tech/p/YZ7Tf9KXTtHpH1w6YL-16bit-Serial-Homebrew-CPU

Building a homebrew CPU from scratch takes a large number of logic chips. It is understandable, that implementing registers, program counter, ALU, and other components of the CPU in TTL or CMOS logic does require a substantial amount of chips. But how many exactly? I've tried to optimize my homebrew CPU for the lowest amount of logic chips possible and answer a question: How few ICs are required for a Turing-complete CPU without a CPU?

My answer is a 16-bit Serial CPU with only 8 ICs, including memory and clock. It has 128kB SRAM, 768kB FLASH, and can be clocked up to 10MHz. It contains only a 1-bit ALU, but the majority of its 52 instructions operate on 16-bit values (serially). At its maximum speed, it executes roughly 12k instructions per second (0.012MIPS) and, among other things, is capable of streaming a video on PCD8544 based (Nokia 5110) LCD at ~10 FPS.

#programming #tech