Xsens » Code » MTi-1_example

Example of using Xbus library to communicate with an MTi-1 series device using a full-duplex UART connection.

Important Information

This example is deprecated and no longer maintained. There are new embedded examples available in the MT SDK folder of the MT Software Suite. For more information please visit: https://xsenstechnologies.force.com/knowledgebase/s/article/Introduction-to-the-MT-SDK-programming-examples-for-MTi-devices

Overview

The example program demonstrates connecting to an MTi-1 series device, restoring communications settings to default if necessary, and configuring the MTi to send data. For an MTi-1 the device is configured to send inertial sensor data, while MTi-2 and MTi-3 devices are configured to output orientation data using the onboard XKF3i filter.

Communication with the MTi-1 series device is implemented using a either a full-duplex UART, I2C or SPI bus. A reset line is used to reset the MTi during initialization. Data is output to a host PC terminal using a second UART.

For more information on the MTi-1 series communication protocol please refer to the datasheet: https://www.xsens.com/download/pdf/documentation/mti-1/mti-1-series_datasheet.pdf

Supported Platforms

The program has been tested on the following mbed platforms:

Using the Example

To use the example program connect one of the supported mbed boards to the host PC and download the application from the mbed online compiler to the target device.
With the mbed board unpowered (USB disconnected) wire the mbed board to the MTi-1 development board. The following connections are required:
- In all cases:
  - 5V (or 3V3) main supply to VDD (P300-1)
  - MCU IO voltage (IORef) to VDDIO (P300-2)
  - GND to GND (P300-3)
  - MT_NRESET to nRST (P300-5)
- For I2C communication:
  - MT_SCL to I2C_SCL (P300-9)
  - MT_SDA to I2C_SDA (P300-11)
  - MT_DRDY to DRDY (P300-15)
  - MT_ADD0 to ADD0 (P300-17)
  - MT_ADD1 to ADD1 (P300-19)
  - MT_ADD2 to ADD2 (P300-21)
- For SPI communication:
  - MT_DRDY to DRDY (P300-15)
  - MT_SCLK to SPI_SCK (P300-17)
  - MT_MISO to SPI_MISO (P300-19)
  - MT_MOSI to SPI_MOSI (P300-21)
  - MT_nCS to SPI_nCS (P300-23)
- For UART communication:
  - MT_RX to UART_TX (P300-9)
  - MT_TX to UART_RX (P300-11)

For more information on the MTi-1 development board please refer to the MTi-1 series user manual: https://www.xsens.com/download/pdf/documentation/mti-1/mti-1-series_dk_user_manual.pdf

Information

Check the defines at the top of main.cpp to determine which IO pins are used for the MT_xxx connections on each mbed platform.

Information

The active peripheral (I2C, SPI or UART) is selected on the MTi-1 development board through the PSEL0 and PSEL1 switches. Look on the bottom of the development board for the correct settings.

Connect to the target using a serial terminal. The application is configured for:
- Baudrate = 921600
- Stop bits = 1
- No parity bits
- No flow control
Reset the mbed board.
You should be presented with a simple user interface as shown below:

MTi-1 series embedded example firmware.
Device ready for operation.
Found device with ID: 03880011.
Device is an MTi-3: Attitude Heading Reference System.
Output configuration set to:
        Packet counter: 65535 Hz
        Sample time fine: 65535 Hz
        Quaternion: 100 Hz
        Status word: 65535 Hz

Press 'm' to start measuring and 'c' to return to config mode.

Diff: main.cpp

Revision:: 54:2e9bb1390c9c
Parent:: 53:3891f4259901
Child:: 55:9a2d6f947f0d

--- a/main.cpp	Fri May 22 16:20:04 2015 +0200
+++ b/main.cpp	Fri May 22 16:20:29 2015 +0200
@@ -11,6 +11,52 @@
  * KIND, EITHER EXPRESSED OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND/OR FITNESS FOR A
  * PARTICULAR PURPOSE.
+
+ * \page Overview Firmware overview
+ *
+ * Example firmware for communicating with an Xsens MTi-1 series motion
+ * tracker (MT).
+ *
+ * The firmware uses the mbed-rtos library to provide RTOS features such as
+ * memory pools and queues. A single thread (main) is used with reception of
+ * data from the motion tracker via a UART handled by interrupts.
+ *
+ * \section Hardware setup
+ * The firmware has been tested with a ST Nucleo F302R8 development board.
+ * The Nucleo board should be connected to the MTi1 development board using the
+ * Arduino compatible headers on the Nucleo board as follows:
+ *
+ * | Nucleo pin | MTi1 func.  | MTi1 dev. pin |
+ * |------------|-------------|---------------|
+ * | IORef      | VDDIO_EXT   | P301-3        |
+ * | 5V         | VDD_EXT     | P301-1        |
+ * | GND        | GND         | P301-2        |
+ * | SCL/D15    | DEV_UART_TX | P301-9        |
+ * | SDA/D14    | DEV_UART_RX | P301-11       |
+ * | D2         | nRST        | P301-7        |
+ *
+ * Communication with the host PC is achieved using the built-in USB serial
+ * bridge of the Nucleo board.
+ *
+ * \subsection Porting
+ * To port to a different mbed platform only the serial Rx/Tx lines and the
+ * reset line pins should need to be updated.
+ *
+ * \section Firmware Operation
+ * The firmware starts by initializing the serial ports used to communicate
+ * with the host PC and with the MT. During the initialization the MT is held
+ * in reset using the nRST input.
+ *
+ * Once the firmware is ready to communicate with the MT the reset line is
+ * released and the firmware waits for a wakeup message from the MT. If this is
+ * not received within 1 second the firmware will try to restore communication
+ * with the MT using a special restore communication procedure.
+ *
+ * When the MT is ready for communication the firmware requests the device ID
+ * of the MT, and based on this determines which type of MTi is connected.
+ * If the MT is an MTi-1 then it will be configured to send inertial and
+ * magnetic measurement data. MTi2 and MTi3 devices have onboard orientation
+ * estimation and will therefore be configured to provide quaternion output.
  */
 
 #include "mbed.h"