Key features:
- Runs on the Pimoroni Pico VGA demo board and Pimoroni Pico DVI demo board (HDMI). Supports sound over on-board DAC. Also supports custom VGA RGB 332 board (PWM sound)
- Provides an immersive full screen experience, with a very fast boot time and no operating system
- Simultaneous USB keyboard and joystick support (using a powered USB hub)
- The small form factor makes the board easy to mount in period or reproduction cases
- Emulates pseudo and Hi-res graphics
- Emulates ZonX and Quicksilva sound
- Emulates QS User Defined Graphics
- Emulation runs at accurate speed of a 3.25MHz ZX81
- Emulates 50Hz and 60Hz display
- Support for up to 320 by 240 pixel display, i.e. 40 character width and 30 character height
- Load .p, .81, .o and .80 files from micro SD Card. Save .p and .o files
- Set-up of emulator (computer type, RAM, Hi-Res graphics, sound, joystick control etc) configurable on a per program basis, using config files
- Optionally displays graphic of keyboard (taken from sz81). Can type in code with keyboard visible
Full source code, documentation, list of tested applications and release binaries can be found at: https://github.com/ikjordan/picozx81
It was a fun exercise that definitely helped me understand the inner workings of the ZX81 in more detail. Hopefully this may prove useful to someone! I’d value any feedback.