Chips › Processors › Early microprocessors › Kenbak-1 logic

Kenbak-1 logic

The Kenbak-1 has no single CPU chip: John Blankenbaker built it in 1971, before the microprocessor existed, so the whole processor is made from TTL small- and medium-scale logic — plain gates, counters and registers wired together on the board. It has three registers (A, B and X), 256 bytes of memory, a full instruction set and all five addressing modes, and is programmed and read back through a front panel of eight lamps and buttons.