detect pin (input) jumped to anoter pin (output)

[iseron]

Hi.

I have to deliver a project in 2 more days and my client asked me about a jumper configuration.

The hardware is done, and i have a PIC16F877 with 4 pins who can be easily jumped or short circuited.
The pins are RA2, RA3, RA4 and RA5 free to do anything.

What happen if i short circuit for example the RA5 with RA4?
What happen if RA4 is configured like an output 1 and RA5 is configured like an input.

Can i do a While instruction without burn the microcontroller?

An example is better...
I have all the routines done, but my need if i have input signal (RA5 for ex.) like a "1" or VCC y can do a specific routine (before was called by rs232 console).


Thanks in advance.
Ignacio.

[valemike]

Well, the PIC starts off as all inputs. Just make sure you don't configure them both as outputs by accident. Better yet, put a current limiting resistor between them just in case.
I don't see why you'd want to shoot a logic level out on RA5 and read it back on RA4, since your program will already know that RA5 is supposed to be high.

[iseron]

Let me explain better.

I have 2 routines programmed.
Now i can choose to run those routines in RS232 console mode. If a press number 1 ---> routine N�1 press number 2 --> routine N�2

Now, i want to run the routine N�1 if i have a jumper ( short circuit) between RA4 and RA5 for example.

Else run routine N�2.

Can i do that? The pic can be burn?

I can't do new modifications to the PCB...
Thanks in advance.