EC1204 – AT89S52 and DS1302 based LED Clock

I built the 1204 Kit and it not working, so lets figure it out

Physical all the joints seem to be good and test out fine


Circuit schmatics

Checking the AT89S52

Verifying the program

I the AT89S52 in an EEPROM programmer and it reads and verifies the program that diffs out with other sources on the internet

But are the ports working?

Checking the output drivers

“2TY” (SOT-23) PNP transistor LED Drive

Simulating so I can better understand the driving circuit to further diagnose


It was a faulty AT89S52, replace and it works.


Props to this site, plenty of awesome info