The Controller Area Network (CAN bus) is a message-based protocol designed to allow the Electronic Control Units (ECUs) found in today's automobiles, as well as other devices, to communicate with each other in a reliable, priority-driven fashion.

Useful repos:

• https://github.com/autowp/arduino-mcp2515 

• https://wiki.seeedstudio.com/CAN-BUS_Shield_V2.0#schematic-online-viewer

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MCP2515 + MCP2551:

The MCP2515 is a stand-alone Controller Area Network (CAN) controller that implements the CAN specification, Version 2.0B. It is capable of transmitting and receiving both standard and extended data and remote frames. The MCP2515 has two acceptance masks and six acceptance filters that are used to filter out unwanted messages, thereby reducing the host MCU’s overhead. The MCP2515 interfaces with microcontrollers (MCUs) via an industry standard Serial Peripheral Interface (SPI).

The MCP2551 is a high-speed CAN, fault-tolerant device that serves as the interface between a CAN protocol controller and the physical bus. the MCP2551 device provides differential transmit and receive capability for the CAN protocol controller, and is fully compatible with ISO-11898 standard, including 24V requirements. It will operate at speed of up to 1Mb/s.

MCP2515 PICTAIL:

The CAN node consists of the MCP2515 Stand-Alone CAN controller and MCP2551 CAN transceiver. The PICkit Plus and PICkit Serial connectors allow the board to be interfaced to a variety of PICmicros so that the user can develop a CAN node. The board also contains headers or test points for most of the MCP2515 pins to allow the external functions to be monitored/evaluated.

https://www.microchip.com/en-us/development-tool/mcp2515dm-ptpls

• Stand-alone CAN controller and CAN transceiver
• PICtail Plus connector for attaching to Explorer 16 and other main boards with the connector
• DB9 connector for connecting to CAN networks using the psuedo standard pinout
• Footprint for terminal block connector for the CAN bus
• Test points for all of the MCP2515 pins