The Build Process

This CPU is a microprogrammed, discrete-component design. In contrast to modern single-chip microprocessors, discrete-component CPUs consist of hundreds of relatively simple individual building-block Integrated Circuits (ICs), laid out on large Printed Circuit Boards (PCBs) and connected together by thousands of individual connections (traces).

The C74-6502 was designed by hobbyists working at home, soldered by hand and built using simple tools and techniques. It consists of some 200 ICs and 4,000 individual solder points laid out on two sister PCBs.

It took two years to complete the design and build the first prototype. See the original build forum thread.

Images From The Build-Process

card a-registers sch p1
Fig. 1 – Sample Schematic
C74-6502 Panel Top V1
Fig. 2 – PCB Layout
Panel Split
Fig. 3 – PCB Panel
Fig. 4 – Populated PCBs
S-PC Patch Detail
Fig. 5 – Layout Patch
CPU Forest
Fig. 6 – First Connections
CPU Debug Setup
Fig. 7 – Debug Setup
LA Setup
Fig. 8 – Taking Measurements
SBC CPU Sandwich
Fig. 9 – CPU Stacked Assembly (with SBC on top)

A big day in the lab — First Life!