GENERAL: Splitting Hex Files

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Information in this article applies to:

• C51 any Version
• C251 any Version
• C166 any Version
• MDK-ARM any Version

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QUESTION

Is there a utility or an easy way to split one Intel HEX file into two or more HEX files. This might be necessary if different Flash banks need to be programmed independently or when a bootloader should be separated from the application.

ANSWER

You may want to consider using the free srec_cat.exe utility which is available as Windows EXE file from https://sourceforge.net/projects/srecord/files/srecord-win32. It is part of the SRecord project hosted on sourceforge.net. With this utility, you can load one or multiple HEX files, cut out specific address areas, move them to a new address and store them to one HEX file.

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

srec_cat.exe HexFile.hex -Intel -crop 0x0000 0x7FFF -o PartHexFile.hex -Intel

You can also invoke this tool after each project build/rebuild by specifying its invocation in the µVision dialog Options for Target - User - After Build/Rebuild. If many parameters are needed, it is easier to use a command file:

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:

• -Disable_Sequence_Warnings
  This option suppresses a warning if records of the input Intel HEX file are not sorted in ascending address order. HEX file generated by OH51 or OHX51 are not sorted in ascending address order.
• -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 bytes (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 for srec_cat.exe. You can even use comments -- starting with '#' extending to the end of the line.

Example 1:

Split one HEX file (HexFile.hex) to two HEX files (HexFilePart1.hex and HexFilePart2.hex) where HexFilePart1.hex should contain the original address range from 0x000000-0x007FFF and HexFilePart2.hex should contain the original address range from 0x008000-0x00FFFF moved down to address 0x000000. Two invocations of srec_cat.exe are necessary to do this:

srec_cat.exe HexFile.hex -Intel -crop 0x000000 0x007FFF -o HexFilePart1.hex -Intel
srec_cat.exe HexFile.hex -Intel -crop 0x008000 0x00FFFF -offset -0x008000 -o HexFilePart2.hex -Intel

Example 2:

This example is identical with example 1 but because some additional srec_cat.exe options are specified, a command file is used to invoke srec_cat.exe two times:

Content of SplitHexPart1.cmd command file:

# BL51 hex files are not sorted for ascending addresses. Suppress this warning
-disable-sequence-warning
# take HexFile.hex address area 0x000000-0x007FFF
.\OBJ\HexFile.hex -Intel -crop 0x000000 0x007FFF
#generate hex records with 16 byte data length (default 32 byte)
-Output_Block_Size=16
# generate a Intel hex file
-o .\OBJ\HexFilePart1.hex -Intel

Content of SplitHexPart2.cmd command file:

# BL51 hex files are not sorted for ascending addresses. Suppress this warning
-disable-sequence-warning
# take HexFile.hex address area 0x008000-0x00FFFF and shift it down to 0x000000
.\OBJ\HexFile.hex -Intel -crop 0x008000 0x00FFFF -offset 0x008000
#generate hex records with 16 byte data length (default 32 byte)
-Output_Block_Size=16
# generate a Intel hex file
-o .\OBJ\HexFilePart2.hex -Intel

Invocation of srec_cat.exe with two command files:

srec_cat.exe @SplitHexPart1.cmd
srec_cat.exe @SplitHexPart2.cmd

MORE INFORMATION

• Refer to SRecord Reference Manual
• Refer to Start External Tools in the µVision User's Guide.
• GENERAL: Converting HEX, Binary, etc. File Formats

SEE ALSO

• GENERAL: Intel HEX File Format
• GENERAL: Utility For Combining Intel Hex Files
• ULINK: Using ULINK as a Device Programmer

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Last Reviewed: Thursday, February 25, 2021

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