Adria is my second attempt to build a simple computer, based on a WDC65C816 CPU.

Design

The backplane has these functions built in:

  • Reset, active low using DS1813+;
  • 7V-25V in – 5V out voltage regulator, LM7805 based;
  • Clock oscillator with divider (/4);
  • One slot for CPU;
  • One slot for MMU/memory decoder;
  • One slot for ROM;
  • 4 available expansion slots;

Specifications

Dimensions:

  • 162mm x 95 mm;
  • M3 unplated mounting holes;
  • Double sided PCB;

Available Signals

Known Issues

  • In the current ordered PCBs a trace between pin 8 and 12 of U3 (74HCT74) is missing. In the new revision of the design, this has been corrected.
  • In a future revision, I might change the 74HCT74 to 74AC74.