can

CAN bus interface: initialise the bus, receive frames with a callback, and transmit standard or extended frames.

Available on: Flexs Q5 Pro

The can object connects the device to a CAN bus. Initialise the bus with a data rate, register a receive handler, and transmit frames with can.tx() — including extended IDs, CAN FD and remote (RTR) frames.

Functions

can.init() — Initialises the CAN bus interface.
can.listen() — Registers a receive handler for incoming CAN frames.
can.tx() — Transmits a CAN frame.

can.init()

can.init(dataRate, canFD, autoRetransmit)

Initialises the CAN bus interface.

Arguments

Name	Type	Required	Default	Description
dataRate	number (kbps)	yes	—	Bus data rate in kbps, e.g. `125`, `250`, `500`.
canFD	boolean	yes	—	Enable CAN FD framing.
autoRetransmit	boolean	yes	—	Enable automatic retransmission.

Example

can.init(125, false, false); // 125 kbps, classic CAN, no auto retransmission

can.listen()

can.listen(callback)

Registers a receive handler for incoming CAN frames.

The callback receives a message object with the frame id and data payload. Decode binary payloads with the bin functions.

Arguments

Name	Type	Required	Default	Description
callback	function	yes	—	Callback `function(msg){ … }` — `msg = { id, data }`.

Example

can.listen(function(msg){
  print(string(msg)); // {"id":164242,"data":"hello from canbus"}
});

can.tx()

can.tx(id, payload, extendedId, canFD, remoteFrame)

Transmits a CAN frame.

Arguments

Name	Type	Required	Default	Description
id	number	yes	—	Frame identifier.
payload	string	yes	—	Frame payload — pack binary data with the `bin` functions.
extendedId	boolean	yes	—	`true` for a 29-bit extended identifier.
canFD	boolean	yes	—	`true` to send as a CAN FD frame.
remoteFrame	boolean	yes	—	`true` to send a remote (RTR) frame.

Example

can.tx(
  12,             // id
  "Test Payload", // payload
  false,          // extended id
  false,          // canFD
  false           // remote frame (RTR)
);