Naresh Krish
Mbed driver for the Stmicroelectronics LIS2MDL sensor
Dependents: itracker-mbed-os-example-lis2mdl
Introduction
The LIS2MDL is an ultra-low-power, high-performance 3-axis digital magnetic sensor.
The LIS2MDL has a magnetic field dynamic range of ±50 gauss.
The LIS2MDL includes an I2C serial bus interface that supports standard, fast mode, fast mode plus, and high-speed (100 kHz, 400 kHz, 1 MHz, and 3.4 MHz) and an SPI serial standard interface.
More details in datasheet here: http://www.st.com/resource/en/datasheet/lis2mdl.pdf
This driver assumes the user will deploy the sensor over I2C. SPI update will be committed soon :)
Sample Code:
LIS2mDL sample program
uint8_t MODR = MODR_100Hz;
int16_t temp[3] = {0, 0, 0};
float magBias[3] = {0,0,0}, magScale[3] = {0,0,0};
// Attach interrupt to this pin if you want to use magnetometer sensor interrupt
// Before that make sure to set the correct interrupt value in the INT_CTRL_REG, INT_THS_L_REG and the INT_THS_H_REG (threshold value)
DigitalIn interruptPin(LIS2MDL_intPin);
// The itracker has the LIS2MDL sensor on the 13 and 11 I2C pins
I2C i2c(p13,p11);
// main() method. Runs in its own thread in the OS
int main()
{
//Create LIS2MDL object
LIS2MDL sensor(i2c, LIS2MDL_ADDRESS);
//Reset the sensor to ensure correct starting config register values
sensor.reset();
wait(3);
//Intialise the CHIP with the MODR value chosen
sensor.init(MODR);
//Test the Chip ID. Should return 64 (0x40)
sensor.getChipID();
// Calcaulte the offset bias to be used in future reading. See self check for example usage
sensor.offsetBias(magBias, magScale);
// Read the internal temp sensor
sensor.readTemperature();
//Get readings from the sensor;
for(int i=0; i<60; i++) {
int16_t temp[3] = {0, 0, 0};
sensor.readData(temp);
wait(0.1);
}
}
Diff: LIS2MDL.h
- Revision:
- 0:d7138994c637
--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/LIS2MDL.h Mon Feb 12 04:59:47 2018 +0000
@@ -0,0 +1,138 @@
+/*
+ Created by Naresh Krishnamoorthy
+
+ The LIS2MDL is a low power magnetometer, here used as 3 DoF solution.
+ Library may be used freely and without limit with attribution.
+*/
+
+#ifndef LIS2MDL_h
+#define LIS2MDL_h
+
+#include "mbed.h"
+
+//*********************************
+//Register map for LIS2MDL'
+// http://www.st.com/content/ccc/resource/technical/document/datasheet/group3/29/13/d1/e0/9a/4d/4f/30/DM00395193/files/DM00395193.pdf/jcr:content/translations/en.DM00395193.pdf
+//*********************************
+#define LIS2MDL_OFFSET_X_REG_L 0x45
+#define LIS2MDL_OFFSET_X_REG_L 0x46
+#define LIS2MDL_OFFSET_X_REG_L 0x47
+#define LIS2MDL_OFFSET_X_REG_L 0x48
+#define LIS2MDL_OFFSET_X_REG_L 0x49
+#define LIS2MDL_OFFSET_X_REG_L 0x4A
+#define LIS2MDL_WHO_AM_I 0x4F
+#define LIS2MDL_CFG_REG_A 0x60
+#define LIS2MDL_CFG_REG_B 0x61
+#define LIS2MDL_CFG_REG_C 0x62
+#define LIS2MDL_INT_CTRL_REG 0x63
+#define LIS2MDL_INT_SOURCE_REG 0x64
+#define LIS2MDL_INT_THS_L_REG 0x65
+#define LIS2MDL_INT_THS_H_REG 0x66
+#define LIS2MDL_STATUS_REG 0x67
+#define LIS2MDL_OUTX_L_REG 0x68
+#define LIS2MDL_OUTX_H_REG 0x69
+#define LIS2MDL_OUTY_L_REG 0x6A
+#define LIS2MDL_OUTY_H_REG 0x6B
+#define LIS2MDL_OUTZ_L_REG 0x6C
+#define LIS2MDL_OUTZ_H_REG 0x6D
+#define LIS2MDL_TEMP_OUT_L_REG 0x6E
+#define LIS2MDL_TEMP_OUT_H_REG 0x6F
+
+#define LIS2MDL_ADDRESS (0x1E << 1)
+
+//******************************
+// MODR legal values
+//******************************
+#define MODR_10Hz 0x00
+#define MODR_20Hz 0x01
+#define MODR_50Hz 0x02
+#define MODR_100Hz 0x03
+
+/** LIS2MDL class.
+ * Used for interfacing with the LIS2MDL sensor on board the itracker
+ */
+class LIS2MDL
+{
+public:
+ /**Public constructor
+ * @param p_i2c Mbed I2C class object
+ * @param addr Address of the I2C object
+ *
+ */
+ LIS2MDL(I2C& p_i2c, uint8_t addr);
+
+ /** init function to set the sensors initialisation parameters
+ * @param MODR See the MODR legal values in the defines in LIS2MDL.h
+ *
+ */
+ void init(uint8_t MODR);
+
+ /** Function to get the CHIP ID
+ *
+ * @return uin8_t returns the chip id. In this can 64
+ * see http://www.st.com/content/ccc/resource/technical/document/datasheet/group3/29/13/d1/e0/9a/4d/4f/30/DM00395193/files/DM00395193.pdf/jcr:content/translations/en.DM00395193.pdf
+ */
+ uint8_t getChipID();
+
+ /** Read the raw sensor data
+ * @params destination pointer to the array that will store the results
+ * see http://www.st.com/content/ccc/resource/technical/document/datasheet/group3/29/13/d1/e0/9a/4d/4f/30/DM00395193/files/DM00395193.pdf/jcr:content/translations/en.DM00395193.pdf
+ */
+ void readData(int16_t * destination);
+
+ /** Function to get the status register value
+ *
+ * @return uint8_t value of the status register
+ * see http://www.st.com/content/ccc/resource/technical/document/datasheet/group3/29/13/d1/e0/9a/4d/4f/30/DM00395193/files/DM00395193.pdf/jcr:content/translations/en.DM00395193.pdf
+ */
+ uint8_t status();
+
+ /** Function to reset the LIS2MDL sensor
+ */
+ void reset();
+
+ /** Function to generate the offset bias stored in the chip as part of the calib
+ * @param dest1 Magnetic Bias offset of the sensor
+ * @param dest2 Magnetic Scale offset of the sensor
+ */
+ void offsetBias(float * dest1, float * dest2);
+
+ /** Function to read the temperature of the internal tempo sensor
+ *
+ * @return uint8_t temperature reading of the internal temp sensor
+ */
+ int16_t readTemperature();
+
+ /** Self check function for the sensor
+ *
+ */
+ void lis2mdlSelfCheck();
+
+ /** I2C function for writing a Byte to the LIS2MDL sensor
+ * @param address address of the sensor
+ * @param subaddress register location to which to write data
+ * @param data data to be written
+ */
+ void writeByte(uint8_t address, uint8_t subAddress, uint8_t data);
+
+ /** I2C function for reading a Byte from the LIS2MDL sensor
+ * @param address address of the sensor
+ * @param subaddress register location to which to write data
+ */
+ uint8_t readByte(uint8_t address, char subAddress);
+
+ /** I2C function for reading many Bytes from the LIS2MDL sensor
+ * @param address address of the sensor
+ * @param subaddress register location to which to write data
+ * @param count number of bytes to read
+ * @param dest pointer to the array which will store the read values
+ */
+ void readBytes(uint8_t address, uint8_t subAddress, uint8_t count, char * dest);
+
+protected:
+ I2C *_i2c_p;
+ I2C &_i2c;
+
+};
+
+#endif
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