The SuperComputer
The project was an exercise in counting. Utilising 5 4017 ICs (of which only 4 were ever wired up) and 4 x 74LS90 ICs.
The 4017 counts sequentially from 1-10 in its purest configuration passing its tenth logic signal to its neighbouring IC as the input. In this manner the 4 processors counted to 10000. The 10000th signal was passed then to the first 74LS90.
The 74LS90 is a Binary decade counter. Similar to the 4017 this IC also counts to 10 in its simplest set up however the output is in a 4bit ‘nibble’. These outputs could theoretically be connected to a decoder and then to a 7 segment LED display.
In this set up they remain in their binary output, with each 4 LEDs representing a number between 0 and 9. As with the 4017 processors, the output at the count of ten is the input of the next. The first 74LS90 is triggered by the 10000th pulse from the 4017 so accumulative the last four lights reset to 0000 when the entire computer has counted to 100,000,000.
I never felt I spun this computer up to its top speed finding it difficult to obtain a fast enough initial clock pulse. Later I connected an adjustable digital variable clock output with variable duty cycle. (time on vs time off).
