Interfaces

• Pin Configuration
  • MTi 600-series module
  • Robust trackers (MTi-630R/670G/680G)
• Communication to host
  • CAN
  • RS232
  • UART
• GNSS receiver interface
• RTCM corrections interface
• SYNC

Pin Configuration

MTi 600-series module

Below figure shows the pin configuration of the MTi 600-series module.

Pin configuration of the MTi 600-series module

Below table shows the pin descriptions of the MTi 600-series module.

Robust trackers (MTi-630R/670G/680G)

The figure below shows the three connectors on the rugged housing of the MTi-670G/680G. The MTi-630R only features the Host Interface connector.

Pin configuration of the MTi-670G/680G

The table below shows the pin descriptions of the MTi-630R/670G/680G Host Interface connector.

The table below shows the pin descriptions of the MTi-680G RTCM corrections connector.

Communication to host

The MTi 600-series is designed to be used as a peripheral device in embedded systems or as a standalone unit. The MTi 600-series supports Controller Area Network (CAN) and RS232 protocols for the communication between the MTi and a host. The module supports an additionally Universal Asynchronous Receiver/Transmitter (UART). See the table below for interface specifications.

A USB and RS422 interface is possible through a UART to USB/RS422 converter (see example in the MTi 600-series Development Kit).

At its core, the MTi uses the Xsens-proprietary Xbus protocol which is compatible with all Xsens Motion Tracker products. This protocol is available on all interfaces; UART, RS232 and CAN.

The MT Low Level Communication Protocol Documentation is a complete reference for the protocol.

CAN

The CAN interface of the MTi-600 does not include a termination resistor; it 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 needs to be added between the CAN_H and CAN_L pins.

For more information, please review the MT CAN Protocol Documentation.

RS232

The RS232 interface complies with the standard RS232 voltage levels. It includes hardware flow control through RTS and CTS lines.

The RTS signal is an output of the MTi-600. If the RTS line is low, the module is busy and unable to receive new data. Otherwise, the module’s UART is idle and ready to receive. The CTS signal is an input for the MTi 600-series. The module checks the state of the CTS line at the start of every byte it transmits. If CTS is high, the module transmits the byte. Otherwise, it postpones transmission until CTS is raised. If flow control is not used, the CTS input should be connected to a logic high to make sure that the MTi 600-series can transmit data. A RS232 logic high voltage should be between +3 V and +25 V.

The CTS signal is an input for the module. The module checks the state of the CTS line at the start of every byte it transmits. If CTS is high, the module transmits the byte. Otherwise, it postpones transmission until CTS is raised. When, during the transmission of a byte, the user lowers the CTS signal, the module completes transmission of that byte before postponing further output. The module will not retransmit this byte. The figure below shows the behaviour of the TX and CTS lines.

Data transmit behaviour under CTS

The RTS signal is an output of the module. If the RTS line is low, the module is busy and unable to receive new data. Otherwise, the module’s UART is idle and ready to receive. After receiving a byte, the direct memory access (DMA) controller of the module will transfer the byte to its receive first-in-first-out (FIFO) buffer. The module will pull down the RTS signal during this transfer. Therefore, with every byte received, the module lowers the RTS line shortly. The figure below shows this behaviour.

RTS behaviour during data reception

The user can use this communication mode without hardware flow control. In this case, the user must tie the CTS line high (e.g. VIN) to make the module transmit.

UART

The UART interface can be used to directly connect to an MCU at 3.3 V IO-levels. The user can configure the MTi 600-series module to communicate over UART. The UART frame configuration is 8 data bits, no parity and 1 stop bit (8N1). The UART protocol only has the TX and RX lines without any flow control. The UART interface is not available on the MTi-630R/670G/680G.

GNSS receiver interface

The MTi-670/680 variants of the MTi 600-series module family support external inputs from a GNSS receiver, such as the u-blox MAX-M8 GNSS receiver. For the GNSS receiver, the RS232 or UART communication pins of the receiver need to be connected to the GNSS_TxD and GNSS_RxD pins of the MTi-670/680 module. In the case of a UART interface on the GNSS receiver, an additional RS232 transceiver should be connected in-between the MTi-600 and the GNSS receiver. See the figure below for connection details and the table below for interface specifications.

The PPS/TIMEPULSE output of the GNSS receiver should be connected to either one of the SYNC inputs of the MTi-670/680. The used SYNC input needs to be configured in software accordingly. Under default configurations, the PPS/TIMEPULSE output should be connected to SYNC_IN2.

Connections for the GNSS interface

RTCM corrections interface

The MTi-680G variant of the MTi 600-series family supports RTCM correction inputs from an external device (e.g. radio module). This input can be found on the 4-pin connector and uses RS232 levels. In the case of a UART interface on the radio module, an additional RS232 transceiver should be connected in-between the MTi-680G and the radio module. See the figure below for connection details and the table below for interface specifications.

Connections for the RTCM corrections interface

SYNC

The MTi 600-series has two multifunctional synchronization inputs and one synchronization output. The electrical specifications can be found in Electrical Specifications. Refer to the MTi 600-series Datasheet for configuration details.