µVISION DEBUGGER: Port 1 Error Message Box

Information in this article applies to:

• Keil PK51 All Versions

QUESTION

I'm running the debugger and I receive the following error message:

PORT 1 ERROR

You have tried to modify a port pin which is configured as output!

Why am I receiving this message?

ANSWER

This error happens when you try to input some data into Port PIN and, at the same time, you're outputting data.

For example, the instruction

P1 ^= 0x01;               /* Toggle P1.0 each time we print */

During the execution of this instruction, if you manually try to change the state of the physical P1.0 PIN ( Pins ) you will receive this error message. It means that you are outputting and inputting a signal over the port pin at the same time.

RESOLUTION

You may modify Port Pins when you are not outputting data over it.

Last Reviewed: Tuesday, February 23, 2021