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INF2004_Project/frtos/magnetometer/magnetometer_init.h

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/**
* @file magnetometer_init.h
* @author Woon Jun Wei
* @brief Initialise the magnetometer sensor and
* calculate the direction of the car
*
* @details This file contains the function prototypes for the
* magnetometer sensor and the function to calculate
* the direction of the car based on the magnetometer sensor data
*/
#ifndef MAGNETOMETER_INIT_H
#define MAGNETOMETER_INIT_H
#include <stdio.h>
#include <math.h>
#include "pico/stdlib.h"
#include "hardware/i2c.h"
#include "pico/binary_info.h"
#include "FreeRTOS.h"
#include "task.h"
#include "message_buffer.h"
#include "semphr.h"
#include "car_config.h"
#include "LSM303DLHC_register.h"
// Semaphores
SemaphoreHandle_t g_direction_sem = NULL;
/**
* @brief Read Data with I2C, given the address and register
* @param addr Address of the device
* @param reg Register to read from
* @return 1 piece of data read from the register
*/
static inline int
read_data(uint8_t addr, uint8_t reg)
{
uint8_t data[1];
// Send the register address to read from
i2c_write_blocking(i2c_default, addr, &reg, 1, true);
// Read the data
i2c_read_blocking(i2c_default, addr, data, 1, false);
return data[0];
}
/**
* @brief Read Accelerometer Data
* @param accelerometer Accelerometer Data
*/
static inline void
read_accelerometer(int16_t accelerometer[3], volatile direction_t *p_direction)
{
uint8_t buffer[6];
buffer[0] = read_data(ACCEL_ADDR, LSM303_OUT_X_L_A);
buffer[1] = read_data(ACCEL_ADDR, LSM303_OUT_X_H_A);
buffer[2] = read_data(ACCEL_ADDR, LSM303_OUT_Y_L_A);
buffer[3] = read_data(ACCEL_ADDR, LSM303_OUT_Y_H_A);
buffer[4] = read_data(ACCEL_ADDR, LSM303_OUT_Z_L_A);
buffer[5] = read_data(ACCEL_ADDR, LSM303_OUT_Z_H_A);
// Combine high and low bytes
// xAcceleration
accelerometer[0] = (int16_t)((buffer[1] << 8) | buffer[0]);
// yAcceleration
accelerometer[1] = (int16_t)((buffer[3] << 8) | buffer[2]);
// zAcceleration
accelerometer[2] = (int16_t)((buffer[5] << 8) | buffer[4]);
// Apply the calibration data
accelerometer[0] -= p_direction->calibration_data->accelerometerBias[0];
accelerometer[1] -= p_direction->calibration_data->accelerometerBias[1];
accelerometer[2] -= p_direction->calibration_data->accelerometerBias[2];
}
/**
* @brief Read Magnetometer Data with Moving Average
* @param magnetometer Magnetometer Data
*/
static inline void
read_magnetometer(int16_t magnetometer[3], volatile direction_t *p_direction)
{
uint8_t buffer[6];
int32_t xMagFiltered = 0;
int32_t yMagFiltered = 0;
int32_t zMagFiltered = 0;
for (int i = 0; i < NUM_READINGS; i++)
{
buffer[0] = read_data(MAG_ADDR, LSM303_OUT_X_H_M);
buffer[1] = read_data(MAG_ADDR, LSM303_OUT_X_L_M);
buffer[2] = read_data(MAG_ADDR, LSM303_OUT_Y_H_M);
buffer[3] = read_data(MAG_ADDR, LSM303_OUT_Y_L_M);
buffer[4] = read_data(MAG_ADDR, LSM303_OUT_Z_H_M);
buffer[5] = read_data(MAG_ADDR, LSM303_OUT_Z_L_M);
// Update the cumulative sum of the magnetometer data
xMagFiltered += (int16_t)(buffer[0] << 8 | buffer[1]);
yMagFiltered += (int16_t)(buffer[2] << 8 | buffer[3]);
zMagFiltered += (int16_t)(buffer[4] << 8 | buffer[5]);
}
// Calculate the moving average
magnetometer[0] = xMagFiltered / NUM_READINGS;
magnetometer[1] = yMagFiltered / NUM_READINGS;
magnetometer[2] = zMagFiltered / NUM_READINGS;
// Apply the calibration data
magnetometer[0] -= p_direction->calibration_data->magnetometerBias[0];
magnetometer[1] -= p_direction->calibration_data->magnetometerBias[1];
magnetometer[2] -= p_direction->calibration_data->magnetometerBias[2];
}
/**
* @brief Read Temperature Data in Degrees Celsius
* @param temperature Temperature Data in Degrees Celsius
*/
static inline void
read_temperature(int16_t temperature[1])
{
uint8_t buffer[2];
buffer[0] = read_data(MAG_ADDR, LSM303_TEMP_OUT_H_M);
buffer[1] = read_data(MAG_ADDR, LSM303_TEMP_OUT_L_M);
/**
* Normalize temperature; it is big-endian, fixed-point
* 9 bits signed integer, 3 bits fractional part, 4 bits zeros
* and is relative to 20 degrees Celsius
* Source: https://electronics.stackexchange.com/a/356964
*/
int16_t raw_temperature
= (20 << 3) + (((int16_t)buffer[0] << 8 | buffer[1]) >> 4);
// Convert the raw temperature data to degrees Celsius
float temperature_celsius = (float)raw_temperature / 8.0;
// Store the result in the temperature array
temperature[0] = (int16_t)temperature_celsius;
}
/**
* @brief Calibrate the Magnetometer Sensor via bias values
*
* @return None
*/
void
initial_calibration(direction_t *p_direction)
{
int16_t accelerometer[3];
int16_t magnetometer[3];
int16_t accelerometerMin[3] = { 0, 0, 0 };
int16_t accelerometerMax[3] = { 0, 0, 0 };
int16_t magnetometerMin[3] = { 0, 0, 0 };
int16_t magnetometerMax[3] = { 0, 0, 0 };
printf("Initial Calibration\n");
for (int i = 0; i < 100; i++)
{
printf("Calibrating... %d\n", i);
read_accelerometer(accelerometer, p_direction);
read_magnetometer(magnetometer, p_direction);
for (int j = 0; j < 3; j++)
{
if (accelerometer[j] > accelerometerMax[j])
{
accelerometerMax[j] = accelerometer[j];
}
if (accelerometer[j] < accelerometerMin[j])
{
accelerometerMin[j] = accelerometer[j];
}
if (magnetometer[j] > magnetometerMax[j])
{
magnetometerMax[j] = magnetometer[j];
}
if (magnetometer[j] < magnetometerMin[j])
{
magnetometerMin[j] = magnetometer[j];
}
}
sleep_ms(10);
}
p_direction->calibration_data->accelerometerBias[0]
= (accelerometerMax[0] + accelerometerMin[0]) / 2;
p_direction->calibration_data->accelerometerBias[1]
= (accelerometerMax[1] + accelerometerMin[1]) / 2;
p_direction->calibration_data->accelerometerBias[2]
= (accelerometerMax[2] + accelerometerMin[2]) / 2;
p_direction->calibration_data->magnetometerBias[0]
= (magnetometerMax[0] + magnetometerMin[0]) / 2;
p_direction->calibration_data->magnetometerBias[1]
= (magnetometerMax[1] + magnetometerMin[1]) / 2;
p_direction->calibration_data->magnetometerBias[2]
= (magnetometerMax[2] + magnetometerMin[2]) / 2;
printf("Accelerometer Bias: %d, %d, %d\n",
p_direction->calibration_data->accelerometerBias[0],
p_direction->calibration_data->accelerometerBias[1],
p_direction->calibration_data->accelerometerBias[2]);
printf("Magnetometer Bias: %d, %d, %d\n",
p_direction->calibration_data->magnetometerBias[0],
p_direction->calibration_data->magnetometerBias[1],
p_direction->calibration_data->magnetometerBias[2]);
}
/**
* @brief Initialise the LSM303DLHC sensor (Accelerometer and Magnetometer)
* @details
* Accelerometer - Normal power mode, all axes enabled, 10 Hz,
* Full Scale +-2g, continuous update
*
* Magnetometer - Continuous-conversion mode, Gain = +/- 1.3,
* Enable temperature sensor, 220 Hz
*
* @return None
*/
static void
LSM303DLHC_init()
{
/**
* Accelerometer Setup
*/
// 0x20 = CTRL_REG1_A
// Normal power mode, all axes enabled, 10 Hz
uint8_t buf[2] = { LSM303_CTRL_REG1_A, 0x27 };
i2c_write_blocking(i2c_default, ACCEL_ADDR, buf, 2, false);
// Reboot memory content (0x40 = CTRL_REG4_A)
// Full Scale +-2g, continuous update (0x00 = 0b0000 0000)
buf[0] = LSM303_CTRL_REG4_A;
buf[1] = 0x00;
i2c_write_blocking(i2c_default, ACCEL_ADDR, buf, 2, false);
/**
* Magnetometer Setup
*/
// MR_REG_M (0x02) - Continuous-conversion mode (0x00 -> 00000000)
buf[0] = LSM303_MR_REG_M;
buf[1] = 0x00;
i2c_write_blocking(i2c_default, MAG_ADDR, buf, 2, false);
// CRB_REG_M (0x01) - Gain = +/- 1.3 (0x20 -> 00100000)
buf[0] = LSM303_CRB_REG_M;
buf[1] = 0x20;
i2c_write_blocking(i2c_default, MAG_ADDR, buf, 2, false);
// CRA_REG_M (0x00), 0x9C = 0b1001 1100
// Enable temperature sensor (0x80 -> 1000 0000)
// 220 Hz (0x1C -> 0001 1100)
buf[0] = LSM303_CRA_REG_M;
buf[1] = 0x9C;
i2c_write_blocking(i2c_default, MAG_ADDR, buf, 2, false);
}
/**
* @brief Initialise the Magnetometer Sensor
* @details Initialise the I2C Port, SDA and SCL Pins, and the LSM303DLHC Sensor
*/
void
magnetometer_init(car_struct_t *p_car_struct)
{
p_car_struct->p_direction->roll = 0;
p_car_struct->p_direction->pitch = 0;
p_car_struct->p_direction->yaw = 0;
p_car_struct->p_direction->target_yaw = 0;
p_car_struct->p_direction->orientation = NORTH;
p_car_struct->p_direction->roll_angle = LEFT;
p_car_struct->p_direction->pitch_angle = UP;
calibration_data_t g_calibration_data
= { .accelerometerBias = { 0, 0, 0 }, .magnetometerBias = { 0, 0, 0 } };
p_car_struct->p_direction->calibration_data = &g_calibration_data;
printf("Magnetometer Initialising\n");
i2c_init(I2C_PORT, 400 * 1000);
gpio_set_function(I2C_SDA, GPIO_FUNC_I2C);
gpio_set_function(I2C_SCL, GPIO_FUNC_I2C);
gpio_pull_up(I2C_SDA);
gpio_pull_up(I2C_SCL);
LSM303DLHC_init();
// initial_calibration();
printf("Magnetometer Initialised\n");
}
/**
* @brief Timer Interrupt Handler To calculate the direction of the car
* @param repeatingTimer The timer handler
* @return True (To keep the timer running)
*/
bool
h_direction_timer_handler(repeating_timer_t *repeatingTimer)
{
BaseType_t xHigherPriorityTaskWoken = pdFALSE;
xSemaphoreGiveFromISR(g_direction_sem, &xHigherPriorityTaskWoken);
portYIELD_FROM_ISR(xHigherPriorityTaskWoken);
return true;
}
#endif
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