The computer’s clock is used to synchronize all operations. The clock we’re building is based on the popular 555 timer IC. The videos go into some detail on the operation of the 555 and use it in three different ways.

Our clock is adjustable-speed (from less than 1Hz to a few hundred Hz). The clock can also be put into a manual mode where you push a button to advance each clock cycle. This will be a really useful feature for debugging the computer later on.

Videos

Schematic

(coming soon!)

Parts list

QuantityDescription
1Breadboard
51kΩ resistor
1100kΩ resistor
11MΩ resistor
11MΩ potentiometer
30.01µF capacitor
20.1µF capacitor
11µF capacitor
3555 timer IC
174LS04 (Hex inverter)
174LS08 (Quad AND gate)
174LS32 (Quad OR gate)
2Double-throw toggle switch
2Momentary 6mm tact switch
1Blue LED