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Tuesday, May 11, 2021

CONTINUITY: Vacuum Tube Computer Part 12: Redesigning the Logic Unit and Building Buffers

After experimenting with an actual MC14500, it's decided to extend the design to support full binary arithmetic including carry, which on the original Motorola design requires lengthy bit-twiddling. Driving the resulting arithmetic and logic unit (ALU) will require more fan-out than the instruction decoder provides, so once again it's time to add buffer circuitry. At this point, the largely repetitive circuitry is complete, and it's time to contemplate the messy random logic which the ALU will require.

Posted at May 11, 2021 11:43