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program counter pt. 2

A project log for 4 bit computer built from discrete transistors

This project is an attempt to teach myself about the inner workings of computers. Naturally I started from the bottom up.

zaphodzaphod 04/14/2014 at 21:540 Comments

I successfully built a quarter of the program counter on perfboard. the bread boarded one and the perfboarded one have been connected and I have a (partially breadboarded) 2-bit program counter, it counts from 0 to 3 and then rolls over to zero again, and can be reloaded with any new address.

for reference the above circuit is 15 perfboard holes tall (1.5 inches)

the above picture is of a completed 2-bit program counter (half of what I will eventually build entirely on the perfboard)

underneath the words 'program counter' over the bread board is some additional logic, specifically an inverter and an AND gate, this is for the reload logic.

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