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CMSIS: E203: Undefined identifier - function 'Message' When Building

Information in this knowledgebase article applies to:

  • MDK-ARM version 5.23
  • CMSIS Pack version 5.0.0


After updating a device family pack, the build output window gives the following error message:

Sequence : CheckID
Context : Item #1:  <control if="jep106id != 0x20">
Item #0:  <block> ::Line 2
Expression : " Message(2, "Not a genuine ST Device! Abort connection.");"
E203 : Undefined identifier - function 'Message'


This error message means means the earlier version of MDK-ARM doesn't understand what the "Messages" function is, in the new pack.

To improve the CMSIS standard, new features are always being added to the specifications. The "Messages" function was a recent edition to the CMSIS-Pack standard version 1.4.9. CMSIS PACK version 5.0.1 (released 23rd of February 2017) and later implements this standard. Keil updated MDK-ARM versions 5.24a (released 5th of July, 2017) and later to be able to use the function "Messages".

The STM32F4 and STM32L4 device family packs (DFP) are some of the first to take advantage of the "Messages" function.


Possible solutions:

  • Update to MDK-ARM version 5.24a and CMSIS Pack version 5.0.1 or later to take advantage of the sequences, queries, and other new debug access functions used in the latest ST packs.
  • Downgrade the ST Device Family pack to one released before February 2017.



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

Last Reviewed: Wednesday, May 16, 2018

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