Emulating an 8080 on an ATtiny85
a day ago
- #Hardware Optimization
- #Microcontroller Emulation
- #Retro Computing
- A vintage microprocessor emulation project uses an ATtiny85, which has limited pins and processing power, to emulate an 8080.
- The emulation is achieved by connecting the ATtiny85 to a Teensy via SPI bus, with the Teensy handling support functions like RAM, ROM, and floppy disk emulation.
- Optimized C code and a 128 byte cache improve performance, making the emulation only slightly slower than a real 8080 when booting CP/M.
- The project includes a full write-up and fake 1975 electronics magazine covers, available on GitHub.
- Comments discuss potential alternatives, such as using an even more constrained ATTiny10 or attaching SPI flash, serial RAM, and a UART chip to the ATtiny85.
- Criticism arises about relying on a Teensy, with comparisons to using external components, but the ATtiny85 alone handles the ISA emulation.
- Historical context is provided, noting that CP/M previously ran on an ATmega88-based emulator over 15 years ago.