It it’s current incarnation, the Steckschwein consists of 4 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 Board (upgraded to V9958)
  4. Sound (YM3812)

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.


Block diagram as PDF