Hi Chris,

I agree with Erik, nothing work, no software nor the hardware.
This is the most usual state, if hardware and software was build the first time.

1.
Try first to test the hardware step by step.
E.g. write a testprogram to toggle a pin to check, if the 8051 work.
If not, check VCC, ALE, RESET, ...

2.
Test all other hardware step by step with small test programs.

3.
If all hardware seems working, test the software step by step.
E.g. reduce it more and more until a specific task work, then add other programm modules again and see, if they work also.
Test all former working things again.

4.
Continue it, until the program contain all modules again and all tasks still working.


There is no other way.
Any CPU is a fast but stupid machine. So any single false bit give the chance to do wrong things. And be sure, if the CPU have the choice, it tends always to do the worst !


I prefer the opposite way:
I start with a small program, download and test it. And then it was expanded more and more with testing after every step.
Thus, why I also prefer in system programming with Flash devices.


Peter