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This example is deprecated and no longer maintained.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.

Files at this revision

API Documentation at this revision

Revision 48:69d35430fe8b, committed 2015-05-21

Comitter:: Alex Young
Date:: Thu May 21 16:45:07 2015 +0200
Parent:: 47:c4610a65dade
Child:: 49:38ecfbff5391
Commit message:: Add documentation for xbusmessage

Changed in this revision

xbus/xbusmessage.c	Show annotated file Show diff for this revision Revisions of this file
xbus/xbusmessage.h	Show annotated file Show diff for this revision Revisions of this file

--- a/xbus/xbusmessage.c	Thu May 21 16:32:53 2015 +0200
+++ b/xbus/xbusmessage.c	Thu May 21 16:45:07 2015 +0200
@@ -17,6 +17,9 @@
 #include "xbusdef.h"
 #include "xbusutility.h"
 
+/*!
+ * \brief Calculate the number of bytes needed for \a message payload.
+ */
 static uint16_t messageLength(struct XbusMessage const* message)
 {
 	switch (message->mid)
@@ -29,6 +32,9 @@
 	}
 }
 
+/*!
+ * \brief Format a message with a pointer to an array of OutputConfiguration elements.
+ */
 static void formatOutputConfig(uint8_t* raw, struct XbusMessage const* message)
 {
 	struct OutputConfiguration* conf = message->data;
@@ -40,6 +46,10 @@
 	}
 }
 
+/*!
+ * \brief Format the payload of a message from a native data type to
+ * raw bytes.
+ */
 static void formatPayload(uint8_t* raw, struct XbusMessage const* message)
 {
 	switch (message->mid)
@@ -57,6 +67,10 @@
 	}
 }
 
+/*!
+ * \brief Format a message into the raw Xbus format ready for transmission to
+ * a motion tracker.
+ */
 size_t XbusMessage_format(uint8_t* raw, struct XbusMessage const* message)
 {
 	uint8_t* dptr = raw;
@@ -96,6 +110,14 @@
 	return dptr - raw;
 }
 
+/*!
+ * \brief Get a pointer to the data correspondind to \a id.
+ * \param id The data identifier to find in the message.
+ * \param data Pointer to the raw message payload.
+ * \param dataLength The length of the payload in bytes.
+ * \returns Pointer to data item, or NULL if the identifier is not present in
+ * the message.
+ */
 static uint8_t const* getPointerToData(enum XsDataIdentifier id, uint8_t const* data, uint16_t dataLength)
 {
 	uint8_t const* dptr = data;
@@ -114,6 +136,12 @@
 	return NULL;
 }
 
+/*!
+ * \brief Read a number of floats from a message payload.
+ * \param out Pointer to where to output data.
+ * \param raw Pointer to the start of the raw float data.
+ * \param floats The number of floats to read.
+ */
 static void readFloats(float* out, uint8_t const* raw, uint8_t floats)
 {
 	for (int i = 0; i < floats; ++i)
@@ -122,6 +150,13 @@
 	}
 }
 
+/*!
+ * \brief Get a data item from a XMID_MtData2 Xbus message.
+ * \param item Pointer to where to store the data.
+ * \param id The data identifier to get.
+ * \param message The message to read the data item from.
+ * \returns true if the data item is found in the message, else false.
+ */
 bool XbusMessage_getDataItem(void* item, enum XsDataIdentifier id, struct XbusMessage const* message)
 {
 	uint8_t const* raw = getPointerToData(id, message->data, message->length);
@@ -161,6 +196,9 @@
 	}
 }
 
+/*!
+ * \brief Get a string descriptions for the passed data identifier.
+ */
 char const* XbusMessage_dataDescription(enum XsDataIdentifier id)
 {
 	switch (id)

--- a/xbus/xbusmessage.h	Thu May 21 16:32:53 2015 +0200
+++ b/xbus/xbusmessage.h	Thu May 21 16:45:07 2015 +0200
@@ -24,6 +24,7 @@
 extern "C" {
 #endif
 
+/*! \brief Xbus message IDs. */
 enum XsMessageId
 {
 	XMID_Wakeup             = 0x3E,
@@ -43,6 +44,7 @@
 	XMID_Error              = 0x42,
 };
 
+/*! \brief Xbus data message type IDs. */
 enum XsDataIdentifier
 {
 	XDI_PacketCounter  = 0x1020,
@@ -56,16 +58,36 @@
 	XDI_StatusWord     = 0xE020,
 };
 
+/*!
+ * \brief An Xbus message structure with optional payload.
+ */
 struct XbusMessage
 {
+	/*! \brief The message ID of the message. */
 	enum XsMessageId mid;
+	/*!
+	 * \brief The length of the payload.
+	 *
+	 * \note The meaning of the length is message dependent. For example,
+	 * for XMID_OutputConfig messages it is the number of OutputConfiguration
+	 * elements in the configuration array.
+	 */
 	uint16_t length;
+	/*! \brief Pointer to the payload data. */
 	void* data;
 };
 
+/*!
+ * \brief Output configuration structure.
+ */
 struct OutputConfiguration
 {
+	/*! \brief Data type of the output. */
 	enum XsDataIdentifier dtype;
+	/*!
+	 * \brief The output frequency in Hz, or 65535 if the value should be
+	 * included in every data message.
+	 */
 	uint16_t freq;
 };