C51: Interrupts Not Generated

Information in this article applies to:

• C51 Version 6.12 and later
• µVision Version 2.12 and later

SYMPTOMS

The compiler is not generating interrupt vectors for my interrupt service routines. What's going on?

CAUSE

Take a look at the compiler command line in the listing file for the interrupt routine with no interrupt vector. For example:

C51 COMPILER V6.12, COMPILATION OF MODULE IOFUNCTIONS
OBJECT MODULE PLACED IN .\IOFunctions.OBJ
COMPILER INVOKED BY: C:\KEIL\C51\BIN\C51.EXE .\IOFunctions.c
     OPTIMIZE(SIZE) BROWSE NOINTPROMOTE NOINTVECTOR
     REGFILE(DD2.reg) DEBUG OBJECTEXTEND CODE LISTINCLUDE
     SYMBOLS PAGELENGTH(46)

If the NOINTVECTOR directive is present, the compiler does not generate interrupt vectors for your interrupts.

RESOLUTION

1. Check your C file to make sure this directive is NOT specified.
2. Check the C51 compiler controls in the Project Options in µVision. The "Interrupt Vectors At Address" check box must be checked to generate interrupt vectors.

MORE INFORMATION

• Refer to NOINTVECTOR in the Cx51 User's Guide.

Last Reviewed: Thursday, February 25, 2021