The Steckschwein is a homebrew 8bit computer based on the 65c02 CPU.
Our initial mission used to be to create a computer that might have existed during the heyday of 8bit home computers. Only with more modern interfaces to the outside world, like SPI for SD card storage instead of floppy disks. Now, having achieved that already quite some time ago, we now try to push the limits of what is possible.
The name “Steckschwein” originates to the very early stages of our project, where everything was prototyped on breadboards (german: “Steckbrett”), and we all know that those things can be real pigs.
First PCB based prototypes
We started off with a very small test circuit, having the 65c02 execute only NOPs, by hard wiring the data lines to $EA. Then, we started to add new components step by step, such as ROM, RAM, IO interface (65c22 VIA), serial interface (UART 16550), until we arrived at the current specifications:
- 65c02-CPU @ 8MHz
- 64k RAM
- 32k bankable ROM
- Video chip TMS9929, now upgraded to V9958
- Sound chip YM3812 (OPL2)
- rs232 via UART 16550
- SPI used as main peripheral bus for:
- sd-card based mass storage
- PS/2-peripheral controller (keyboard, mouse) (ATmega8)
- RTC (Maxim DS1306)
Further reading and more details on Steckschwein Hardware.