Matt’s entry in the Open 7400 Logic competition: Discrete logic POV clock.
This persistence-of-vision clock was built entirely out of discrete logic chips. The design consists of three boards, a LED array and a drive motor. The digit board keeps the time while the display board controls the LEDs.
The digit board
Every second, a pulse increments the value stored in a counter. When it overflows, the next counter is incremented. Each counter represents a digit in the time. A decoder selects one digit at a time and puts that digit’s value on the output bus.
The display board
A pulse from an external source wakes up the display board. It selects the leftmost digit from the digit board, formats it for a 7-segment-display, and chops up the result into a 5 x 5 pixel matrix. It lights up LEDs for each column in sequence then selects the next digit to the right.
Via the contact form
Cool project man, well done!
Thanks Arthur! It was a great learning experience.
i hope doing it …………in order to respect those IC which gave birth to controllers
55001901 DISCRETE LOGIC BOARD V2