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GENERAL: Making Hex Files from Binary Files

Information in this article applies to:

  • Keil ARM All Versions
  • C51 All Versions
  • C251 All Versions
  • C166 All Versions


I need to create a HEX file from a BINARY file. Where can I find a utility that does that?


You may want to consider using the free srec_cat.exe utility which is available as Windows EXE file from It is part of the SRecord project hosted on With this utility, you can load one or multiple BINARY files, cut out specific address areas, move them to a new address and store them to a HEX file.

You can invoke srec_cat.exe from a Windows command prompt or Make tool:

srec_cat.exe BinaryFile.bin -Binary -o HexFile.hex -Intel

You can also invoke this tool before or after each project build/rebuild by specifying its invocation in the µVision dialog Options for Target - User - Before/After Build/Rebuild. You can use µVision key sequences as parameter for srec_cat.exe. If many parameters are needed, it may be easier to use a command file. When using a command file for srec_cat.exe, be sure to double the '@' character, or µVision might interpret it as a key-sequence.

For a full description of all srec_cat.exe parameters, refer to the SRecord Reference Manual. Here are some options which are useful with Keil tools:

  • -address-length= 2 or 3 or 4
    Specifies the number of address bytes in the Intel HEX output file. By default, srec_cat generates extended address records (type 04) for an address range of up to 4GB. Since a code banked application is bigger than 64K, -address-length=2 must not be used before specifying the output file. This would limit the max. address space to 64K.
  • -Output_Block_Size= ByteCount
    Specifies the length of each HEX record. By default, srec_cat generates lines containing up to 32 bytes of data. If you want to limit the max. line length to 16 byte (compatible to OH51, OHX51, OH251 or OH166), use -Output_Block_Size=16.
  • -fill FillValue StartAddress EndAddress
    Fills unused areas with the specified constant value. A fill value of 0xFF is often used with this option because it corresponds to erased Flash.
  • -crop StartAddress EndAddress
    Only loads the specified address area from the previous input file. This option can be combined with -offset.
  • -offset Offset
    Adds an address offset to the previous input file. Positive or negative values are allowed. This option can be combined with -crop.
  • -Intel
    Can be used after an input or output filename to specify that an input file should be interpreted as an Intel HEX file or an output file should be generated as an Intel HEX file.
  • -Binary
    Can be used after an input or output filename to specify that an input file should be interpreted as a binary file or an output file should be generated as a binary file.
  • @CommandFile
    A command file can contain some or all invocation parameters of srec_cat.exe. You can even use comments starting with '#' extending to the end of the line.


If you want to convert the first 16K of a 32K BINARY file (BinaryFile.bin) (address range 0x000000-0x007FFF) to a HEX file (HexFile.hex) where the data should start at address 0x08010000, you can use the following srec_cat.exe command file:

# take BinaryFile.bin address area 0x000000-0x003FFF and add an offset of 0x08010000
.\OBJ\BinaryFile.bin -Binary -crop 0x000000 0x003FFF -offset 0x08010000
# generate a HEX file
-o .\OBJ\HexFile.hex -Intel

Invocation of srec_cat.exe with command file:

srec_cat.exe @CommandFile



Last Reviewed: Thursday, February 25, 2021

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