Configuring CAN through Xbus

• Termination Resistor
• General CAN configuration messages

The MTi 600-series, Xsens Avior series and Xsens Sirius series support a CAN output. The Xsens Avior series and Xsens Sirius series also support CAN input. The CAN communication must be configured through the UART or RS232 interface using Xbus messages. The method of configuring is described below. For more information on Xbus and its message structure, please review the MT Low Level Communication Protocol Documentation.

Termination Resistor

• Xsens Avior series: There is a 120 Ohm termination resistor on the Avior series development board (the standalone Avior series module does not have a termination resistor).
• Xsens Sirius series: The Sirius series devices have an internal 120 Ohm termination resistor which is disabled by default, and can be enabled.  
• MTi 600 series: The MTi-600 series devices do not have an internal 120 Ohm termination resistor. They can be used in a CAN bus that already incorporates the required termination. If used in a single-device connection, a 120 Ω termination resistor must be added between the CAN_H and CAN_L pins.

General CAN configuration messages

ReqCanConfig                      

            MID              230 (0xE6)

            DATA            n/a

            Direction      To MT

            Valid in         Config State

Request the current CAN configuration – see SetCanConfig for information about the data field of the received ReqCanConfigAck acknowledgement message.

SetCanConfig

            MID              230 (0xE6)

            DATA            CAN enable flag (1bit) , Baud rate code (1byte)

            Direction      To MT

            Valid in         Config State

Set the general configuration settings of the CAN-Bus

Example usage:

• Enable regular CAN at 500k birate:
  • FA FF E6 04 00 00 01 0A 0C 

• Enable CAN-FD at 500k nominal bitrate and 2M data bitrate

  • FA FF E6 04 00 00 D3 0A 3A

BAUDRATE

The BAUDRATE is a 1-byte code that specifies at which rate the CAN bus will send data. The CAN peripheral is internally automatically configured to best match a Sample-Point of 70% to 75%.

CAN config settings

Available CAN baud codes

* Bit timing configuration parameters may be subject to change in future firmware releases. 

ReqCanOutputConfig

            MID              232 (0xE8)

            DATA            n/a

            Direction      To MT

            Valid in         Config State

Request the general configuration settings of the CANBus.

SetCanOutputConfig

            MID              232 (0xE8)

            DATA            Xsens CAN data id (7 bits) , ID length flag (1bit), ID mask (29 bits), Output frequency (11 bits)

            Direction      To MT

            Valid in         Config State

Set the output configuration of the CAN-Bus.

The data is a repeating sequence of Xsens CAN data id, ID length flag (11- or 29-bit length, indicated by the value 0 or 1), ID mask, Output frequency. See the figure below for the message structure, and the table below for the Xsens CAN Data Identifiers.

The maximum number of different output messages that can be configured is 16.

SetCanOutputConfig structure

CAN Output Configuration

Xsens CAN Identifiers