View source for Controller Area Network (CAN)

The '''Controller Area Network''' (CAN) represents an essential vehicle bus standard. It was explicitly engineered to facilitate communication between microcontrollers and devices without resorting to a central computer. The primary purpose of CAN is to enhance vehicle interconnectivity and foster swift data exchange between various systems within the vehicle.

== MCP2515 ==

The '''MCP2515''' is an integrated circuit produced by Microchip Technology, constructed to function as a stand-alone CAN controller. It exhibits compatibility with an SPI (Serial Peripheral Interface) which makes it versatile in various applications. Although its primary use is in automotive industries, it is also used in a variety of other control applications.<ref>MCP2515 Stand-Alone CAN Controller with SPI Interface. Microchip Technology. [https://www.microchip.com/wwwproducts/en/en010406 Official datasheet].</ref>

The MCP2515 bridges the connection between the CAN protocol and the SPI protocol by receiving CAN messages and translating them into SPI data, allowing the microcontroller to interpret the information. Similarly, it transforms SPI data into CAN messages for transmission.<ref>MCP2515 Stand-Alone CAN Controller with SPI Interface. Microchip Technology. [https://www.microchip.com/wwwproducts/en/en010406 Official datasheet].</ref>

The MCP2515's operational details include its capacity to support CAN 2.0A and B, drawing attention to its alignment with established CAN standards and equipping it for both basic and extended frame format usage.<ref>MCP2515 Stand-Alone CAN Controller with SPI Interface. Microchip Technology. [https://www.microchip.com/wwwproducts/en/en010406 Official datasheet].</ref>

== Applications  ==

The [https://python-can.readthedocs.io/en/stable/ python-can] library provides Controller Area Network support for Python, providing common abstractions to different hardware devices, and a suite of utilities for sending and receiving messages on a CAN bus.

There is an example of an installation on [[Jetson_Orin]] here.

=== Pi4 ===

Raspberry Pi offers an easy to deploy 2-Channel Isolated CAN Bus Expansion HAT which allows to quickly integrate it to the peripheral devices. See the [https://www.waveshare.com/wiki/2-CH_CAN_HAT tutorial] for more information

=== Arduino ===

Arduino has a good support of the MCPs with many implementations of the [https://github.com/Seeed-Studio/Seeed_Arduino_CAN drivers]

=== MCP2515 Driver ===

By default the CAN bus node is supposed to acknowledge every message on the bus whether or not that node is interested in the message. However, the interference on the network can drop some bits during the communication. In the standard mode, the node would not only continuously try to re-send the unacknowledged messages, but also after a short period it would start sending error frames and then eventually go to bus-off mode and stop. This causes sever issues when the CAN network works with multiple motors.

The controller has a [http://ww1.microchip.com/downloads/en/DeviceDoc/MCP2515-Stand-Alone-CAN-Controller-with-SPI-20001801J.pdf one-shot] setup that requires changes in the driver.

=== Wiring ===

Here is some suggested equipment for wiring a CAN bus:

* Molex Mini-Fit Junior connectors
** [https://www.digikey.ca/en/products/detail/molex/0638190901/9655931 Crimper]
** [https://www.digikey.ca/en/products/detail/molex/0766500013/2115996 Connector kit]
** [https://www.aliexpress.us/item/3256805730106963.html Extraction tool]
* CAN bus cable
** [https://www.digikey.ca/en/products/detail/igus/CF211-02-01-02/18724291 Cable]
** [https://www.digikey.com/en/products/detail/igus/CF891-07-02/21280679 Alternative Cable]
* Heat shrink
** [https://www.amazon.com/Eventronic-Heat-Shrink-Tubing-Kit-3/dp/B0BVVMCY86 Tubing]

== References ==
<references />

[[Category:Communication]]