Are there any errors associated with the CAN Controller on the STM32F205ZGT6 MCU which could explain the CAN bus packet failures when the ambient temperature is increased to 40°C?

[MColl.5]

Hi,

I wonder if you can help us? In one of our projects we are using the STM32F205ZGT6 Microcontroller and specifically we are using the CAN bus. The problem is that when we increase the ambient temperature around the MCU to approximately 38°C to 40°C, we start to loose packets. The MCU is rated for Industrial Temperatures. The CAN bus bit rate that we are using is 250KHz. I have tried to increase the temperature just in the area of the CAN transceivers and not in the areas of the MCU and we have no problems, the CAN communication functions okay. But in the area of the MCU, when the temperature is increased, we obtain CAN bus packet ID errors. So the problem appears to be in the area of the MCU.

Are there any known bugs assocciated with the CAN Controller on the STM32F205ZGT6 MCU, that is not mentioned in the Errate document?

Any ideas is much appreciated.

Best regards,

Matthew 

[Javier1]

Are you using an external XTAL as HSE?

Because if youre not , the internal HSI clock freq could be drifting just enough with temperature to give you this kind of errors.

You could test this by outputing a PWM to one of your MCu pins and monitoring the freq as you increase the temperature.

I had the same issue but my CANBUS baudrate was 150kbps and the temperature i had issues with was around 120ºC

*i was also messing around with the canbus time quantas and i pused up the temperature at which this problem was happening

[MColl.5]

Hi Javier,

Thank you for your quick reply. Our software guys were for some reason using the HSI clock and not the HSE clock as you suggested, When they switched to the external HSE clock, the temperature issue was not a problem anymore.

Thanks again,

Matthew

[Javier1]