Incorrect DMA Interrupt Handler Generated for STM32C091xx (LL-Driver)

[Kadir]

Environment Details

• Microcontroller: STM32C091CBTx (LQFP48)
• STM32CubeMX Version: 6.14.1
• LL-Driver

1. Configuration: An STM32CubeMX project is configured for an STM32C091CBTx MCU, with DMA channel 6 assigned to a peripheral (ADC).
2. Generated Code (stm32c0xx_it.c): Upon code generation, CubeMX creates the shared interrupt handler for DMA channels 4, 5, 6, and 7 in the stm32c0xx_it.c file. The function is defined as:

   void DMAMUX1_DMA1_CH4_5_6_7_IRQHandler(void)

3. Startup File Vector Table (startup_stm32c091xx.s): However, the default startup file provided with the project contains an incorrect entry for this interrupt vector. The handler name in the vector table is listed as:

   DMAMUX_DMA1CH4_5_IRQHandler

Consequently, the `DMAMUX1_DMA1_CH4_5_6_7_IRQHandler` function is never invoked when an attempt is made to trigger DMA Channel 6.

Confirmed Workaround

The issue can be resolved by manually editing the startup file:

1. In the `startup_stm32c091xx.s` file,
2. Search for the incorrect vector name: `DMAMUX_DMA1CH4_5_IRQHandler`.
3. Rename it to `DMAMUX1_DMA1_CH4_5_6_7_IRQHandler`.

Following this modification, the DMA interrupt for channel 6 is successfully triggered and handled by the ISR.

[Ghofrane GSOURI]

Hello @Kadir 

I'm currently investigating this issue.

I will get back to you asap

THX

Ghofrane

[Ghofrane GSOURI · Accepted solution]

Hello @Kadir 

Your contribution is greatly appreciated.

The issue has been escalated to the development team for resolution. The internal ticket number is 214319  .

I will keep you posted with updates.

THX

Ghofrane

[Noëlie_Jestin]

Hello the bug is still here, I drop here the repport

Title: STM32CubeMX generates incorrect DMA IRQ handler name for STM32C091xx (DMAMUX1_DMA1_CH4_5_6_7 vs CH4_5)

Component/Tool: STM32CubeMX (code generation)

MCU: STM32C091KBT6 (STM32C0 family)

FW Package: STM32Cube FW_C0 V1.4.0

Existing community report: https://community.st.com/t5/stm32cubemx-mcus/incorrect-dma-interrupt-handler-generated-for-stm32c091xx-ll/td-p/823392

Description:

STM32CubeMX generates an incorrect DMA interrupt handler name in stm32c0xx_it.c and stm32c0xx_it.h for the STM32C091xx target.

Generated code (incorrect):

// In stm32c0xx_it.c / stm32c0xx_it.h
void DMAMUX1_DMA1_CH4_5_6_7_IRQHandler(void)

Startup vector table (correct symbol):

// In startup_stm32c091kbtx.s (provided by ST)
.word DMAMUX1_DMA1_CH4_5_IRQHandler

The handler name DMAMUX1_DMA1_CH4_5_6_7_IRQHandler generated by CubeMX does not match the symbol DMAMUX1_DMA1_CH4_5_IRQHandler defined in the startup file startup_stm32c091kbtx.s. Since the startup file declares this symbol as weak aliased to Default_Handler, the linker silently resolves the interrupt vector to Default_Handler (an infinite loop) instead of the user's ISR.

Root cause analysis:

The STM32C091 has DMA1 channels 1-5 (not 1-7 like larger STM32C0 variants). The startup vector table correctly uses DMAMUX1_DMA1_CH4_5_IRQHandler, but CubeMX code generation uses the name from a larger variant (CH4_5_6_7), creating a mismatch. This appears to be a device variant mapping error in CubeMX's code generation templates.

Impact: Any DMA transfer on channels 4-5 (e.g., USART4 RX DMA in our case) triggers Default_Handler instead of the correct ISR, causing a hard crash (infinite loop). This is a silent failure — the code compiles and links without any warning or error because the weak attribute masks the mismatch.

Regression behavior: This bug is reintroduced on every CubeMX code regeneration, since CubeMX overwrites stm32c0xx_it.c and stm32c0xx_it.h outside of USER CODE sections. This forces developers to manually patch the handler name after every regeneration, which is error-prone and defeats the purpose of the code generator.

Workaround: Manually rename DMAMUX1_DMA1_CH4_5_6_7_IRQHandler to DMAMUX1_DMA1_CH4_5_IRQHandler in both stm32c0xx_it.c and stm32c0xx_it.h after each CubeMX regeneration.

Steps to reproduce:
1. Create a new STM32CubeMX project for STM32C091KBT6
2. Enable DMA on any peripheral using DMA1 channel 4 or 5 (e.g., USART4 RX)
3. Generate code
4. Compare the handler name in stm32c0xx_it.c with the vector table in startup_stm32c091kbtx.s
5. Observe the mismatch: DMAMUX1_DMA1_CH4_5_6_7_IRQHandler vs DMAMUX1_DMA1_CH4_5_IRQHandler

Expected fix: CubeMX should generate DMAMUX1_DMA1_CH4_5_IRQHandler (matching the startup vector table) for STM32C091xx targets.

---

Edited to apply source code formatting - please see How to insert source code for future reference.

[Ghofrane GSOURI]

Hello @Noëlie_Jestin 

Ticket 214319 has not been implemented yet; it will be fixed as soon as possible.

I will keep you posted with updates.

THX

Ghofrane

[Noëlie_Jestin]

Thanks! This is good to know (it was very tricky to find the bug ^^")