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Jul 4, 2025 8:54 AM UTC
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Bidirectional Communication Between CM4 and CM7 on STM32H747I-DISCO

 

Working on bidirectional communication between CM4 and CM7 on the STM32H747I-DISCO using FreeRTOS stream buffers (CoreMessageBuffer). One-way communication works fine (either CM4 → CM7 or CM7 → CM4), but both directions at the same time do not work as expected.


What Works:

  • CM4 → CM7: Data is sent and received correctly.

  • CM7 → CM4: Works fine when used independently.


Current Issue:

  • When both directions are enabled simultaneously, it fails to receive data in both the direction.

Memory Section Mapping:

Configured dedicated sections for each direction in both CM4 and CM7 linker files:

.ld
/* CM4 → CM7 */ .xCoreMessageBuffer_section_CM4_to_CM7 : { *(.xCoreMessageBuffer_section_CM4_to_CM7) } > RAM_D3_Z1 .xStreamBufferStruct_section_CM4_to_CM7 : { *(.xStreamBufferStruct_section_CM4_to_CM7) } > RAM_D3_Z2 .ucStorageBuffer_section_CM4_to_CM7 : { *(.ucStorageBuffer_section_CM4_to_CM7) } > RAM_D3_Z3 /* CM7 → CM4 */ .xCoreMessageBuffer_section_CM7_to_CM4 : { *(.xCoreMessageBuffer_section_CM7_to_CM4) } > RAM_D3_Z4 .xStreamBufferStruct_section_CM7_to_CM4 : { *(.xStreamBufferStruct_section_CM7_to_CM4) } > RAM_D3_Z5 .ucStorageBuffer_section_CM7_to_CM4 : { *(.ucStorageBuffer_section_CM7_to_CM4) } > RAM_D3_Z6

These sections are defined in both CM4 and CM7 projects for shared memory access.

 

What is the issue? If any example code is there for the same can you please provide it!

This topic has been closed for replies.
Saket_OmBest answer
ST Technical Moderator
Jul 4, 2025 2:31 PM UTC

Hello @Shealtiel 

Please refer to the example below: 

STM32CubeH7/Projects/STM32H747I-EVAL/Applications/OpenAMP/OpenAMP_RTOS_PingPong at master · STMicroelectronics/STM32CubeH7 · GitHub

In order to give better visibility on the answered topics, please click on 'Best answer' on the reply which solved your issue or answered your question. Saket_Om

1 reply

Saket_OmBest answer
ST Technical Moderator
Jul 4, 2025 2:31 PM UTC
In order to give better visibility on the answered topics, please click on 'Best answer' on the reply which solved your issue or answered your question. Saket_Om