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Information in this article applies to:

  • C251 Version 3.20
  • µVision2 Version 2.20


I have created a project that uses NCONST space. I have verified the MAP file and all NCONST segments are correctly placed in the MAP file. However the HEX file does not contain any of my NCONST data. What's wrong?


By default, the 251 toolchain creates a 64KB HEX file for the address range 0xFF0000-0xFFFFFF which is the 8051-compatible address range.

To get a HEX file that contains the memory image for the whole 16MB address space of the 251, you must select the INTEL HEX386 format and specify the address range 0x000000-0xFFFFFF.

Use the following command line if you OH251 from the command prompt.

OH251 filename H386 RANGE (0 - 0xFFFFFF)

If you use µVision2, you must make the following selections on the Output Tab of the Project Options dialog.

  • Create HEX File
  • HEX Format: HEX-386
  • Start: 0
  • End: 0xFFFFFF


Last Reviewed: Sunday, October 29, 2006

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