I2C, CAN BUS, DMA

[Soniaa12]

Hello,

I’m working on a project with an STM32F446RE where I read data from a CAN bus at 500 kbps (CAN1_RX0) and also use I2C to control an MCP4725 DAC, plus timers and DMA for other tasks.

The problem:

• When I test CAN alone, it works perfectly — I can receive all messages from my device (a motorcycle inverter).

• When I run the full code with all peripherals connected and active (CAN + I2C + TIM2 + DMA), the CAN stops receiving after a short time, or doesn’t receive at all.

• On the motorcycle, this happens consistently, but on the bench with CAN only, it works fine.

What I tried so far:

1. Set CAN NVIC priority higher than other interrupts:

2. Confirmed CAN1_RX0_IRQHandler() calls HAL_CAN_IRQHandler(&hcan1).

3. Reduced I2C timeout to avoid blocking (HAL_I2C_Master_Transmit with 2 ms instead of HAL_MAX_DELAY).

4. Tried opening the CAN filter (mask = 0) to receive all IDs for debugging.

5. Enabled HAL_CAN_ErrorCallback 

Despite all these changes, when all peripherals are running in the motorcycle environment, CAN stops working (no messages received) while I2C and timers keep running.

My questions:

• Could this still be an interrupt priority problem?

• Is there something else that could block CAN reception without triggering Bus-Off or errors?

Any advice or similar experience would be appreciated.

I have attached my main code

Thank you.

[mƎALLEm]

Hello,

You said:

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@Soniaa12 wrote:

• When I test CAN alone, it works perfectly

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Then you said: 

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@Soniaa12 wrote:

• Is there something else that could block CAN reception without triggering Bus-Off or errors?

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Are you sure CAN is working well for a long time when it is alone?. I don't think Bus-Off is something linked to adding more modules but to something in the HW or software linked to the CAN itself.

[Karl Yamashita · Accepted solution]

Your code shows you are using ADC and you mention all the other peripherals but it. You haven't attached your stm32xxx_hal_msp.c file so don't know if the ADC is using DMA in circular mode?

In a project I was working on, I had issues having ContinuousConvMode enabled in that the ADC was always interrupting and certain interrupts would not interrupt. I disabled it and I just used a timer to start the ADC conversion periodically. Try disabling the ContinuousConvMode and see if it makes a difference.