In it’s current incarnation, the Steckschwein consists of 3 main units:

  1. CPU/Memory
  2. IO (VIA 65c22), now also including UART
    1. SPI-Devices
    2. UART 16550
    3. Joysticks and user port
  3. Video / audio board with V9958 VDP and YM3812 (OPL2) sound chip

The 62c22 VIA is mainly utilized as SPI master to implement SPI as the main peripheral bus, connecting SD-card, RTC and the ATmega8 (used as PS/2 controller) to the system. The block diagram shows how things are working together.

Schematics, pcb layouts and firmware can be found at our Github repository.


Block diagram as PDF