Voltage issues

A project log for JACA 1 & 2 Homebrew Computer

JACA - Just Another CPU Again Homebrew CPU, starting by a simple POC 4-bit CPU on circuit simulator soft. (done), then 8-bit (in progress)

Andre BaptistaAndre Baptista 04/09/2018 at 12:060 Comments

Last weekend I faced a (not so) unexpected problem when connecting together all modules: a huge tension drop across the circuit. The IC's fartest from power source are just under 4V! As many of you may know TTLs are guaranted to work only between 4.75 and 5.25V. Surprisingly the behaviour is perfect even at this extreme conditions, which  shows how over dimensioned they are. Even the closest IC is with 4,8V.

Possible solutions:

-Use wires direct from power source to each breadboard, not daisy chaining them;

-Use a regulable power suplly and set it to 5.2V as shown in this fantastic series of the channel WR Kits: Building an 8-bit computer (in portuguese), based on the famous Ben Eater breadboard computer.

See you next time.