Programming the 89C51RX+ series requires a 12 volt power source.

The micro has a special powerup sequence, that if you can duplicate, puts it not into program-run mode, but a hidden serial hex-file download mode to program itself.

You have to manipulate 4 microprocessor lines to do this, I'll get the specification and post the solution. You need also download Philip's WINISP program from their homepage. This runs on a Windows PC and handles to communications to the microprocessor.

-Jay C. Box