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Customization Files

The Cx51 Compiler provides a number of source files you may modify to adapt your target program to a specific hardware platform. These files contain:

  • Code that executes upon startup (STARTUP.A51)
  • Code that initializes static variables (INIT.A51)
  • Code that performs low-level stream I/O
  • Code for memory allocation

The code contained in these files is already compiled or assembled and included in the C library. When you link your program, the code from the library is automatically included.

You may customize these files to adjust them to your requirements. If you are working with µVision IDE, we recommend that you copy the customization file in your project folder to make modifications. The modified version of the file can be added the same way as other source files to your project.

When you are working with command-line tools, you must include the object files of the modified customization files in the linker command line. The following example shows you how to include custom replacement files for STARTUP.A51 and PUTCHAR.C:


The file XBANKING.A51 allows you to change the configuration of the extended far memory access routines.

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