Phase 2: waste not want not

Its funny because I am involved in a bunch of projects and I cycle through them as time permits. Just recently got back to EGWU ... I had already written the uart code and monitor program but couldnt reliable test it until I had fixed my voltage regulation problem.

THE PROBLEM IS THAT THE 5V AND 3.3V REGULATORS ARE STILL RUNNING INCREDIBLY HOT. SO MUCH SO I COULDNT KEEP A THUMB ON IT FOR LONGER THAN A SECOND

alas there is NO immediate fix other than a more sensible redesign (perhaps with TO-220 parts and heatsinks and larger copper pour area or with switching regulators). Ill deal with that in the next revision of the design and layout.

Last week my office tossed out two p4 PC's and I salvaged their power supplies. I figured Id use them to generate 5v and 3.3v reliably so I can get on with firmware and fpga development.

This evening I removed the 3.3v and 5v regulators (ams1117 parts) and soldered in 1 pin headers for 5v, 3.v and gnd at the P2/P3/P31 test points. Thus the wisdom in adding those test points during the layout.

Then I went online and grabbed the pin out for the 20 pin ATX motherboard power connector and dug into the PSU box with cutters and my soldering iron.

NOTE: the green wire must be grounded for the power supply to turn on. its designated PS/ON . ALSO some pin positions have both large and small wires - both must be connected to together for the PSU to work.

The color coding is simple
black  = common ground
green  = PS/ON (must be connected to ground)
red      = +5v
orange = +3.3v

Thats all I need, pics below.

Next post resumes software/firmware development