65xxx Emulator on STM32
Posted: Fri Feb 20, 2026 9:45 pm
I'd like to present my system, which I've been working on for some time.
It's based on the popular STM32H750 microcontroller, which can be programmed to emulate older computer systems.
https://stm32-base.org/boards/STM32H750 ... 7XX-M.html
Currently, it can be used to run programs for the i8080, 65C02, and WDC65C816 processors. It can also be used to program ARM processors.
All you need for programming is an external terminal.
Each emulated processor has an additional debug mode with the TRACE function, which tracks program execution.
I'm currently using Apple 1 emulation and a system compatible with the Kowalski Simulator program: https://sbc.rictor.org/kowalski.html
To emulate the Apple 1, I replaced the tape recorder support with an additional serial port. Additional processors can be emulated, and their kernels are stored in system RAM. In the case of the 65816, emulation from EPROM leaves 512 KB of RAM for programs. Running emulation from RAM leaves 448 KB available, but is faster.
I've added several new instructions to the 65c02 emulator to provide access to the STM32H750 registers, allowing access to the system's I/Os.
The chip can function as a microcontroller.
It's based on the popular STM32H750 microcontroller, which can be programmed to emulate older computer systems.
https://stm32-base.org/boards/STM32H750 ... 7XX-M.html
Currently, it can be used to run programs for the i8080, 65C02, and WDC65C816 processors. It can also be used to program ARM processors.
All you need for programming is an external terminal.
Each emulated processor has an additional debug mode with the TRACE function, which tracks program execution.
I'm currently using Apple 1 emulation and a system compatible with the Kowalski Simulator program: https://sbc.rictor.org/kowalski.html
To emulate the Apple 1, I replaced the tape recorder support with an additional serial port. Additional processors can be emulated, and their kernels are stored in system RAM. In the case of the 65816, emulation from EPROM leaves 512 KB of RAM for programs. Running emulation from RAM leaves 448 KB available, but is faster.
I've added several new instructions to the 65c02 emulator to provide access to the STM32H750 registers, allowing access to the system's I/Os.
The chip can function as a microcontroller.
- Emu 65816 & TRACE