What is the difference between loopback mode and normal mode in CAN of STM32F10X MCU

[bruce2]

Posted on July 09, 2013 at 16:55

Hi everyone, I am using a demo board STM3210C-SK to investigate the STM32F10X MCU, especially its CAN functionality. I use Coocox rather than the IAR environment to compile and debug. The sample code is to use CAN 1 to transmit a CAN message and use looping or interrupt method to receive the incoming message. The loopback mode is OK, which Tx is internally connected to Rx. But when I change the mode from loopback to normal mode, the transmission status is always ''pending'' and not successful. On the demo board, the Tx and Rx of CAN is connected to a CAN transceiver SN65HVD230. 

Can anybody give me a hint what is missing when I switch the CAN operating mode from loopback to normal mode? THANKS!

[Tesla DeLorean]

Posted on July 09, 2013 at 17:27

Loopback mode means it doesn't leave the part, and thus the transceiver and other devices on the bus are not required. Make sure you have the transceiver correctly configured, and you're talking to some other device.