Carter John / Mbed 2 deprecated LSM303DLHC_magnetometer_example

An example on how to read raw data

Dependencies:   mbed

main.cpp@0:fb4503358bc7, 2017-07-20 (annotated)

Committer:
ElectronicsSanta
Date:
Thu Jul 20 08:41:07 2017 +0000
Revision:
0:fb4503358bc7
first commit

Who changed what in which revision?

UserRevisionLine numberNew contents of line
ElectronicsSanta 0:fb4503358bc7 1 #include "mbed.h"
ElectronicsSanta 0:fb4503358bc7 2 #include <algorithm> // for min, max functions
ElectronicsSanta 0:fb4503358bc7 3
ElectronicsSanta 0:fb4503358bc7 4 #define MAGN_I2C_ADDRESS (0x1E << 1)
ElectronicsSanta 0:fb4503358bc7 5
ElectronicsSanta 0:fb4503358bc7 6 #define LSM303_REGISTER_MAG_OUT_X_H_M 0x03
ElectronicsSanta 0:fb4503358bc7 7 #define LSM303_REGISTER_MAG_OUT_X_L_M 0x04
ElectronicsSanta 0:fb4503358bc7 8 #define LSM303_REGISTER_MAG_OUT_Z_H_M 0x05
ElectronicsSanta 0:fb4503358bc7 9 #define LSM303_REGISTER_MAG_OUT_Z_L_M 0x06
ElectronicsSanta 0:fb4503358bc7 10 #define LSM303_REGISTER_MAG_OUT_Y_H_M 0x07
ElectronicsSanta 0:fb4503358bc7 11 #define LSM303_REGISTER_MAG_OUT_Y_L_M 0x08
ElectronicsSanta 0:fb4503358bc7 12
ElectronicsSanta 0:fb4503358bc7 13 #define LSM303_REGISTER_MAG_CRA_REG_M 0x00
ElectronicsSanta 0:fb4503358bc7 14 #define LSM303_REGISTER_MAG_CRB_REG_M 0x01
ElectronicsSanta 0:fb4503358bc7 15 #define LSM303_REGISTER_MAG_MR_REG_M 0x02
ElectronicsSanta 0:fb4503358bc7 16 #define LSM303_REGISTER_MAG_OUT_X_H_M 0x03
ElectronicsSanta 0:fb4503358bc7 17 #define LSM303_REGISTER_MAG_OUT_X_L_M 0x04
ElectronicsSanta 0:fb4503358bc7 18 #define LSM303_REGISTER_MAG_OUT_Z_H_M 0x05
ElectronicsSanta 0:fb4503358bc7 19 #define LSM303_REGISTER_MAG_OUT_Z_L_M 0x06
ElectronicsSanta 0:fb4503358bc7 20 #define LSM303_REGISTER_MAG_OUT_Y_H_M 0x07
ElectronicsSanta 0:fb4503358bc7 21 #define LSM303_REGISTER_MAG_OUT_Y_L_M 0x08
ElectronicsSanta 0:fb4503358bc7 22 #define LSM303_REGISTER_MAG_SR_REG_Mg 0x09
ElectronicsSanta 0:fb4503358bc7 23 #define LSM303_REGISTER_MAG_IRA_REG_M 0x0A
ElectronicsSanta 0:fb4503358bc7 24 #define LSM303_REGISTER_MAG_IRB_REG_M 0x0B
ElectronicsSanta 0:fb4503358bc7 25 #define LSM303_REGISTER_MAG_IRC_REG_M 0x0C
ElectronicsSanta 0:fb4503358bc7 26 #define LSM303_REGISTER_MAG_TEMP_OUT_H_M 0x31
ElectronicsSanta 0:fb4503358bc7 27 #define LSM303_REGISTER_MAG_TEMP_OUT_L_M 0x32
ElectronicsSanta 0:fb4503358bc7 28
ElectronicsSanta 0:fb4503358bc7 29 // MD1 MD0
ElectronicsSanta 0:fb4503358bc7 30 #define LSM303_REGISTER_MAG_MR_REG_CCM 0x00 // 0 0 = continuous-conversion mode
ElectronicsSanta 0:fb4503358bc7 31 #define LSM303_REGISTER_MAG_MR_REG_SCM 0x01 // 0 1 = single-conversion mode
ElectronicsSanta 0:fb4503358bc7 32 #define LSM303_REGISTER_MAG_MR_REG_SM 0x02 // 0 1 = sleep-mode. device is placed in sleep-mode
ElectronicsSanta 0:fb4503358bc7 33
ElectronicsSanta 0:fb4503358bc7 34 #define LSM303_REGISTER_MAG_CRA_REG_M_0_75HZ (0 << 2) // 0.75 Hz
ElectronicsSanta 0:fb4503358bc7 35 #define LSM303_REGISTER_MAG_CRA_REG_M_1_5HZ (1 << 2) // 1.5 Hz
ElectronicsSanta 0:fb4503358bc7 36 #define LSM303_REGISTER_MAG_CRA_REG_M_3_0HZ (2 << 2) // 3.0 Hz
ElectronicsSanta 0:fb4503358bc7 37 #define LSM303_REGISTER_MAG_CRA_REG_M_7_5HZ (3 << 2) // 7.5 Hz
ElectronicsSanta 0:fb4503358bc7 38 #define LSM303_REGISTER_MAG_CRA_REG_M_15HZ (4 << 2) // 15 Hz
ElectronicsSanta 0:fb4503358bc7 39 #define LSM303_REGISTER_MAG_CRA_REG_M_30HZ (5 << 2) // 30 Hz
ElectronicsSanta 0:fb4503358bc7 40 #define LSM303_REGISTER_MAG_CRA_REG_M_75HZ (6 << 2) // 75 Hz
ElectronicsSanta 0:fb4503358bc7 41 #define LSM303_REGISTER_MAG_CRA_REG_M_220HZ (7 << 2) // 220 Hz
ElectronicsSanta 0:fb4503358bc7 42
ElectronicsSanta 0:fb4503358bc7 43 #define LSM303_MULTIPLE_REGISTER_READS (1 << 7) // MSB set to 1 in the command is telling the LSM303 to increment the register pointer after each read/write (https://www.pololu.com/product/1268)
ElectronicsSanta 0:fb4503358bc7 44
ElectronicsSanta 0:fb4503358bc7 45 Serial serial(SERIAL_TX, SERIAL_RX);
ElectronicsSanta 0:fb4503358bc7 46 I2C i2c(I2C_SDA, I2C_SCL); // PB_9, PB_8
ElectronicsSanta 0:fb4503358bc7 47 Timer elapsed_time;
ElectronicsSanta 0:fb4503358bc7 48
ElectronicsSanta 0:fb4503358bc7 49 int16_t x;
ElectronicsSanta 0:fb4503358bc7 50 int16_t y;
ElectronicsSanta 0:fb4503358bc7 51 int16_t z;
ElectronicsSanta 0:fb4503358bc7 52 bool magn_found = false;
ElectronicsSanta 0:fb4503358bc7 53
ElectronicsSanta 0:fb4503358bc7 54 uint8_t i2c_read8_reg(uint8_t address, int8_t reg) {
ElectronicsSanta 0:fb4503358bc7 55 char i2cBuffer[1];
ElectronicsSanta 0:fb4503358bc7 56 i2cBuffer[0] = reg;
ElectronicsSanta 0:fb4503358bc7 57 i2c.write(address, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 58
ElectronicsSanta 0:fb4503358bc7 59 i2c.read(address, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 60
ElectronicsSanta 0:fb4503358bc7 61 return (uint8_t)i2cBuffer[0];
ElectronicsSanta 0:fb4503358bc7 62 }
ElectronicsSanta 0:fb4503358bc7 63
ElectronicsSanta 0:fb4503358bc7 64 void i2c_write8_reg(uint8_t address, int8_t reg, int8_t value) {
ElectronicsSanta 0:fb4503358bc7 65 char i2cBuffer[2];
ElectronicsSanta 0:fb4503358bc7 66 i2cBuffer[0] = reg;
ElectronicsSanta 0:fb4503358bc7 67 i2cBuffer[1] = value;
ElectronicsSanta 0:fb4503358bc7 68 i2c.write(address, i2cBuffer, 2);
ElectronicsSanta 0:fb4503358bc7 69 }
ElectronicsSanta 0:fb4503358bc7 70
ElectronicsSanta 0:fb4503358bc7 71 void read_magn() {
ElectronicsSanta 0:fb4503358bc7 72 char i2cBuffer[1];
ElectronicsSanta 0:fb4503358bc7 73
ElectronicsSanta 0:fb4503358bc7 74 i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_X_H_M;
ElectronicsSanta 0:fb4503358bc7 75 i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 76 i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 77 x = (i2cBuffer[0] << 8);
ElectronicsSanta 0:fb4503358bc7 78
ElectronicsSanta 0:fb4503358bc7 79 i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_X_L_M;
ElectronicsSanta 0:fb4503358bc7 80 i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 81 i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 82 x |= i2cBuffer[0];
ElectronicsSanta 0:fb4503358bc7 83
ElectronicsSanta 0:fb4503358bc7 84 i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_Y_H_M;
ElectronicsSanta 0:fb4503358bc7 85 i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 86 i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 87 y = (i2cBuffer[0] << 8);
ElectronicsSanta 0:fb4503358bc7 88
ElectronicsSanta 0:fb4503358bc7 89 i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_Y_L_M;
ElectronicsSanta 0:fb4503358bc7 90 i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 91 i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 92 y |= i2cBuffer[0];
ElectronicsSanta 0:fb4503358bc7 93
ElectronicsSanta 0:fb4503358bc7 94 i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_Z_H_M;
ElectronicsSanta 0:fb4503358bc7 95 i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 96 i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 97 z = (i2cBuffer[0] << 8);
ElectronicsSanta 0:fb4503358bc7 98
ElectronicsSanta 0:fb4503358bc7 99 i2cBuffer[0] = LSM303_REGISTER_MAG_OUT_Z_L_M;
ElectronicsSanta 0:fb4503358bc7 100 i2c.write(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 101 i2c.read(MAGN_I2C_ADDRESS, i2cBuffer, 1);
ElectronicsSanta 0:fb4503358bc7 102 z |= i2cBuffer[0];
ElectronicsSanta 0:fb4503358bc7 103 }
ElectronicsSanta 0:fb4503358bc7 104
ElectronicsSanta 0:fb4503358bc7 105 int main() {
ElectronicsSanta 0:fb4503358bc7 106 serial.baud(115200);
ElectronicsSanta 0:fb4503358bc7 107 i2c.frequency((uint32_t)100e3);
ElectronicsSanta 0:fb4503358bc7 108
ElectronicsSanta 0:fb4503358bc7 109 serial.printf("LSM303DLHC magnetometer example...\n");
ElectronicsSanta 0:fb4503358bc7 110
ElectronicsSanta 0:fb4503358bc7 111 // set the magnetometer data output rate (Hz)
ElectronicsSanta 0:fb4503358bc7 112 i2c_write8_reg(MAGN_I2C_ADDRESS, LSM303_REGISTER_MAG_CRA_REG_M, LSM303_REGISTER_MAG_CRA_REG_M_3_0HZ);
ElectronicsSanta 0:fb4503358bc7 113
ElectronicsSanta 0:fb4503358bc7 114 // read the magnetometer register for the value we set above
ElectronicsSanta 0:fb4503358bc7 115 uint8_t default_val = i2c_read8_reg(MAGN_I2C_ADDRESS, LSM303_REGISTER_MAG_CRA_REG_M);
ElectronicsSanta 0:fb4503358bc7 116
ElectronicsSanta 0:fb4503358bc7 117 if (default_val == LSM303_REGISTER_MAG_CRA_REG_M_3_0HZ) {
ElectronicsSanta 0:fb4503358bc7 118 magn_found = true;
ElectronicsSanta 0:fb4503358bc7 119 serial.printf("magn found\n");
ElectronicsSanta 0:fb4503358bc7 120 } else {
ElectronicsSanta 0:fb4503358bc7 121 serial.printf("magn NOT found\n");
ElectronicsSanta 0:fb4503358bc7 122 }
ElectronicsSanta 0:fb4503358bc7 123
ElectronicsSanta 0:fb4503358bc7 124 if (magn_found) {
ElectronicsSanta 0:fb4503358bc7 125 // enable the magnetometer
ElectronicsSanta 0:fb4503358bc7 126 i2c_write8_reg(MAGN_I2C_ADDRESS, LSM303_REGISTER_MAG_MR_REG_M, LSM303_REGISTER_MAG_MR_REG_CCM);
ElectronicsSanta 0:fb4503358bc7 127
ElectronicsSanta 0:fb4503358bc7 128 elapsed_time.start();
ElectronicsSanta 0:fb4503358bc7 129
ElectronicsSanta 0:fb4503358bc7 130 while (true) {
ElectronicsSanta 0:fb4503358bc7 131 if (elapsed_time.read_ms() > 200) { // print every x ms
ElectronicsSanta 0:fb4503358bc7 132 read_magn();
ElectronicsSanta 0:fb4503358bc7 133 elapsed_time.reset();
ElectronicsSanta 0:fb4503358bc7 134 serial.printf("x: %d; y: %d; z: %d\n", x, y, z);
ElectronicsSanta 0:fb4503358bc7 135 serial.printf("**************************\n");
ElectronicsSanta 0:fb4503358bc7 136 }
ElectronicsSanta 0:fb4503358bc7 137 }
ElectronicsSanta 0:fb4503358bc7 138 }
ElectronicsSanta 0:fb4503358bc7 139 }