Keil common warning reason analysis

EL-C1600N100013-B

SMD LED

There are several common warnings in keil. Of course, the degree of warning is less than the severity of the error, sometimes ignored, and unexpected errors occur. Let's take a look at some common mistakes and analyze the reasons.

1. Warning 280: 'i': unreferenced local variable

Explain that the local variable i does not have any access operations in the function.

Solution to eliminate the declaration of i variables in the function

2 Warning 206: 'Music3': missing function-prototype

Explain that the Music3() function is not declared or not declared externally, so it cannot be called by other functions.

The solution is to write void Music3 (void) written at the front end of the program to declare that if it is a function of other files, it should be written as extern void Music3 (void), which is an external declaration.

3 Compling :C:\8051\MANN.C

Error:318:can't open file 'beep.h'

Note: In the process of compiling C:\8051\MANN.C program, main.c used the instruction #include "beep.h", but it could not be found.

Solution Write an include file for beep.h and save it in the working directory of c:\8051

4 Compling: C:\8051\LED.C

Error 237: 'LedOn': function already has a body

Explain that the LedOn() function name is repeatedly defined, that is, there are more than two identical function names.

Solution Fix one of the function names so that the function names are independent

5 ***WARNING 16:UNCALLED SEGMENT,IGNORED FOR OVERLAY PROCESS

SEGMENT: ?PR?_DELAYX1MS?DELAY

Explain that the DelayX1ms() function is not called by other functions and also occupies program memory space.

Solution Remove the DelayX1ms() function or use the conditional compilation #if .....#endif to keep the function and not compile

6 ***WARNING 6 :XDATA SPACE MEMORY OVERLAP

FROM : 0025H

TO: 0025H

Description 0025H repeated definition address of external data ROM

Solution The external data ROM is defined as follows

Pdata unsigned char XFR_ADC _at_0x25 where the name of the XFR_ADC variable is 0x25, please check if there are other variable names defined at 0x25 and fix it

7 WARNING 206: 'DelayX1ms': missing function-prototype

C:\8051\INPUT.C

Error 267 : 'DelayX1ms ':requires ANSI-style prototype C:\8051\INPUT.C

The program has called the DelayX1ms function but the function is not defined, the program content is not written or the function is defined but not declared.

Solution Write the content of DelayX1ms and declare it as an announcement or external declaration. It can be declared external in the inclusion file of delay.h for other function calls.

8 ***WARNING 1:UNRESOLVED EXTERNAL SYMBOL

SYMBOL: MUSIC3

MODULE: C:\8051\MUSIC.OBJ(MUSIC)

***WARNING 2:REFERENCE MADE TO UNRESOLVED EXTERNAL

SYMBOL: MUSIC3

MODULE: C:\8051\MUSIC.OBJ(MUSIC)

ADDRESS: 0018H

In the program, the MUSIC function is called but the extended file C of the function is not added to the project file Prj for compilation and connection.

Solution Set the MUSIC3 function to add MUSIC C to the project file in MUSIC C.

9 ***ERROR 107: ADDESS SPACE OVERFLOW

SPACE: DATA

SEGMENT: _DATA_GOUP_

LENGTH: 0018H

***ERROR 118: REFERENCE MADE TO ERRONEOUS EXTERNAL

SYMBOL: VOLUME

MODULE: C:\8051\OSDM.OBJ (OSDM)

ADDRESS: 4036H

The address range of the data storage space is 0~0x7f. When the number of common variables and the local variables in the function are set to SMALL, the local variables first use the working registers R2~R7 for temporary storage. When the memory is not enough, the data type is used. If the number of other spaces for temporary storage exceeds 0x7f, the address will be insufficient.

The solution is to modify the public variable defined by the data type to the definition of the idata type.

10 “*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL”

*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL

If you are using the C51 compiler with the above warning, this is just a mistake that beginners and careless people will make: no C files added to the project!

In addition, it is possible that there are already defined functions that have not been called, or that the associated defined variables are not used.

“*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL”

*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL

If you are using the C51 compiler with the above warning, this is just a mistake that beginners and careless people will make: no C files added to the project!

In addition, it is possible that there are already defined functions that have not been called, or that the associated defined variables are not used.

“*** WARNING L1: UNRESOLVED EXTERNAL SYMBOL”

*** WARNING L2: REFERENCE MADE TO UNRESOLVED EXTERNAL

If you are using the C51 compiler with the above warning, this is just a mistake that beginners and careless people will make: no C files added to the project!

In addition, it is possible that there are already defined functions that have not been called, or that the associated defined variables are not used.