LX51: LOCATING PROGRAM OR VARIABLES TO SPECIAL AREAS

Information in this article applies to:

• C51 Version 7

QUESTION

I am writing an IAP loader and would like to locate it in the first 1024 Bytes of my CODE memory. How can I ensure this? I have tried to use wildcards, but this did not work out, since it collidates with interrupt vectors.

ANSWER

The best approch is to locate the program code with a USER CLASS. User classes are an extension of the LX51 Linker/Locater (which is available in the PK51 Professional Developer's Kit).

For example, you can write the following pragma within the C source files that contain the IAP loader program code:

#pragma userclass (code = IAP)    // generates CODE_IAP class

This userclass directive places the program code of the module to the memory class CODE_IAP. Now you can separately locate this memory class when you enter it in µVision under Project - Options for Target - LX51 Locate - User Class. To locate the IAP code to the first 1KB of your program section enter here.

CODE_IAP (C:0 - C:0x3FF)

Note that you have to select the Use Extended Linker LX51 under Project - Options for Target - LX51 Locate - User Class.

MORE INFORMATION

• Refer to USERCLASS in the Cx51 User's Guide.
• Refer to CLASSES in the LX51 User's Guide.

SEE ALSO

• C51: ABSOLUTE FUNCTION ADDRESS
• BL51: LOCATING GROUPS OF CODE SEGMENTS TOGETHER
• LX51: LOCATING A SEGMENT'S ENDING ADDRESS
• C51: REDIRECTING INTERRUPT VECTORS

FORUM THREADS

The following Discussion Forum threads may provide information related to this topic.

• include a c function within an assembler project
• IAP loader
• Link Problem
• Questions about XBanking
• Locating code into a segment

Last Reviewed: Thursday, August 17, 2006