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GENERAL: Converting HEX, Binary, etc. File Formats

Information in this article applies to:

  • C166 any version
  • C251 any version
  • C51 any version
  • MDK any version


What Options are there for manipulating converting HEX and Binary file formats? There are older tools that did this, but they do not run on 64-bit operating systems.


The command line utility srec_cat.exe is an excellent and more versatile replacement for HEX2BIN, BIN2HEX, BIN2MOT and MOT2BIN.

This tool is part of the SRecord package version 1.64 hosted on SRECORD contains utilities to read and manipulate Intel HEX files in many ways. From the summary page of that site:

"The SRecord package is a collection of powerful tools for manipulating EPROM load files. It reads and writes numerous EPROM file formats, and can perform many different manipulations."

Other useful features of srec_cat.exe:

  • Reads Hex files made by Keil OH51, OHX51, OH251 or OH166 or fromelf.exe
  • Always stores Intel HEX records in ascending order
  • Can be invoked from within the Keil IDE
  • Runs on Windows OS

Sections in this article:


Please see the following knowledgebase articles how HEX and BINARY files can be converted, merged and split using the srec_cat.exe utility together with Keil microcontroller development tools.

General HEX File Manipulation

HEX File Manipulation for 8051 Devices

HEX File Manipulation for ARM Devices

General BINARY File Manipulation

Other Applications


Setup the tools to execute srec_cat.exe after each project build/rebuild.

  1. Open µVision
  2. Select the drop down menu Project -> Options for Target** and click on the User tab
  3. Below After Build/Rebuild Check the box for Run #1
  4. For user command, call srec_cat.exe with command options. The key sequence #H can be used for the input hex file name.
  5. For Example:
srec_cat.exe #H -Intel -o SortedHexFile.hex -Intel

Note: If many parameters are needed, it is easier to use a command file. When using a command file for srec_cat.exe in µVision, 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:

  • -DisableSequenceWarnings
    Suppress the warning message that the HEX records of the input file are not sorted in ascending address order. OH51, OHX51, OH251 or OH166 cannot generate HEX files with ascending address order.
  • -address-length= 2 or 3 or 4
    The number of address bytes in the Intel HEX output file (default is 4: generate extended address records (type 04) for an address range of up to 4GB). In the command string, address-length must be before -o (specify an output file).
    For non-code-banked 8051 applications: avoid generating extended address records. Set -address-length=2 to limit the maximum address space to 64K. Code banked application can be larger than than 64K.
  • -OutputBlockSize= ByteCount
    The length of each HEX record (default is 32: lines contain up to 32 bytes of data).
    For C51, C251, C166 applications: set -OutputBlockSize=16 (compatible with OH51, OHX51, OH251 or OH166).
  • -fill FillValue StartAddress EndAddress
    Fills unused areas with the specified constant value.
    Suggestion: use the value 0xFF - this corresponds to value of erased flash.
  • -crop StartAddress EndAddress
    Only loads the specified address area from the previous input file. Combine this option with -offset.
  • -offset Offset
    Add an address offset to the previous input file. Positive or negative values are allowed. Combine this option with -crop.
  • -Intel
    Treat the preceding file name as Intel Hex, e.g., [input filename] -Intel = interpret the input file as an Intel HEX, or [output filename] -Intel = generate an output file in Intel HEX
  • -Binary
    treat the preceding file name is a binary, e.g., [input filename] -Binary = interpret the input file as a binary, or [output filename] -Binary = generate an output file in binary
  • @CommandFile
    A command file can contain some or all invocation parameters for srec_cat.exe.
    Tip: Start a line with '#' to comment everything to the end of that line.
  • -Motorola
    Can be used after an input or output filename to specify that an input file should be interpreted as a Motorola S-Record file or an output file should be generated as a Motorola S-Record file.
  • -C-Array filename [-INClude]
    Can be used after an output filename to specify that it should be generated as a C-source file with an optional include file.





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

Last Reviewed: Monday, July 23, 2018

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