hie. help please. i am using a pic15f877a on my project. the problem is, its displaying digits randomly. its not responding to inputs, i am using a 20Mhz crystal oscilator external. at times the outputs voltage falls as low as 1v. switch off power then on the output voltage is ok, i.e. 4.9v its just random. simulating with proteus, the circuit and the program works well, i dont know what the is problem. will replacing the pic helpfull? i used GCBASIC as the compiler.

 

Would you provide a schematic of the design as well as some source?

 

If you replace the PIC and it exhibits the same problems you will have ruled out that it is the pic causing the problems.

Take a step back and work on things one at a time.

What is this display?

What are these inputs? Digital or analog?

What do you use to measure outputs? Could the part you are driving load down to see 1V, or are you using a DMM so a fast pulse appears as 1V?

As mitko89 suggests, schematic and code are essential to aid you.

 

schematic attached

 

schematic attached

Very nice. What about the rest?

 

I guess this is a case then the noble art (but so often ignored) of debugging comes in