topic Re: CAN in LPC Microcontrollers

CAN

Nadia — Wed, 26 May 2021 13:26:29 GMT

Hi all, I am using the LPC54616, and I need to use the CAN protocol, I have seen that there are two CAN lines, a TD transmission line and a RD reception line.
Do I need a transceiver?

If so, would the MCP2551 work for me?

Thank you all very much. Best regards

Re: CAN

frank_m — Wed, 26 May 2021 14:09:57 GMT

> Do I need a transceiver?
> If so, would the MCP2551 work for me?

Yes to both questions.

Re: CAN

Nadia — Wed, 26 May 2021 14:26:52 GMT

@frank_m THANK YOU VERY MUCH!!!

Re: CAN

Nadia — Wed, 26 May 2021 14:42:29 GMT

@frank_m But then what are the CAN outputs of the microcontroller for? If the transceiver with one transmitter and one receiver is enough.

Re: CAN

frank_m — Thu, 27 May 2021 06:09:31 GMT

Check the CANbus specification, e.g. on Wikipedia. The signal is pseudo differential, with H/L (or 1/0) levels different from the digital signal of the MCU pins. Therefore you need a transceiver.

If you want to test CAN on board level (without a real CAN network), you can get away without a transceiver, if both nodes in close proximity.

Most CAN peripherals use this for a configurable loop-back mode, were the Tx signal is fed directly back to the Rx signal. Usually for test purposes.

Setting up a larger CAN network is not really trivial, I would suggest an experienced mentor if you want/need to do so.