Different stm32F103 behaving differently

[Gladson]

I have purchased STM32F103c8t6 microcontrollers from three different vendors, but they are behaving differently.

I am working on CAN, and on the microcontrollers from one vendor, it is working properly. But on the microcontrollers from other two vendors it is having issues with receiving CAN data. I am using same firmware on all microcontrollers and the CAN bus hardware is also same. by just replacing the microcontroller from different vendors I am having issues.

So, what could be the issue which is causing the receiving issues with microcontroller. I tried lowering the baud rate from 500,000 to 40,000 as I thought that it is having issues with high frequency. but it still is not working. The problem is only for receiving, it is able to transmit properly. I also set a breakpoint inside the receive callback function, but the program is not even going there.

 

The microcontroller which is working properly

 

 

The microcontrollers which have issues with receiving data.

 

 

[Peter BENSCH]

I am 100% sure that there is at least one counterfeit among your devices, which can/will always happen if you buy STM32 from unauthorised dealers. You should check the devices again carefully, for which there are now a number of tools from users, e.g. from GreaseWeazle

Good luck!
/Peter

[lossofphase]

Thank you for posting this! I have been having a fit with trying to get my computer to communicate with my STM32F103C8T6 through USB (using my Arduino IDE) after I've uploaded a bootloader to the module (6 different STM32 modules actually). I'm convinced it's because these are counterfeit chips now.