PiCAN Evaluation board question

[vikash23]

Hi,

I started learning CAN bus network and I found a evaluation kit to interface with Rasberry Pi.

**broken link removed**

They have used MCP2515 CAN controller with MCP2551 CAN transceiver.

My question is why do we need a controller? Why cant the TXD and RXD of the MCP2551 can be connected directly to the TX and RX of the Rasberry Pi ?

 

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CAN transceiver (Layer 1: Physical)
CAN controller (Layer 2: Data-Link/Protocol)

You could write the protocol layer in software, but have no idea if the Pi is fast enough to meet the 1 Mbps maximum transfer rate of CAN.