mpu6050 v0.1.0

MPU-6050 six-axis IMU driver.

Application scenarios

• Tilt and orientation sensing.
• Motion detection or a shake counter.
• A logger for acceleration and angular rate.

Contract

typedef struct {
    int16_t accel_x, accel_y, accel_z;
    int16_t gyro_x, gyro_y, gyro_z;
    int16_t temperature;
} mpu6050_raw_t;

typedef struct {
    int32_t accel_x_mg, accel_y_mg, accel_z_mg;
    int32_t gyro_x_mdps, gyro_y_mdps, gyro_z_mdps;
    int32_t temperature_milli_celsius;
} mpu6050_scaled_t;

uint8_t mpu6050_init(mpu6050_t *device, mpu6050_port_t port, uint8_t i2c_address);
uint8_t mpu6050_read_raw(mpu6050_t *device, mpu6050_raw_t *raw);
uint8_t mpu6050_read_scaled(mpu6050_t *device, mpu6050_scaled_t *scaled);

• init checks WHO_AM_I (0x68), resets, wakes, and sets a 1 kHz sample

rate with a 44 Hz digital low-pass filter.

• read_raw reads a 14-byte burst from 0x3B.
• read_scaled converts to mg, milli-degrees/s, and milli-degrees Celsius.
• Returns 1 on success, 0 on a bus error or a wrong identity.

Parameters

• Default ranges: accelerometer +-2 g, gyroscope +-250 degrees/s.
• Change the range in the adapter or extend the scale factors.
• I2C address 0x68 or 0x69.

Memory and timing

• About 4 bytes plus the caller's result struct.
• A burst read is 14 bytes; no delays after init.

Integration

mpu6050_t imu;
mpu6050_raw_t raw;
mpu6050_init(&imu, board_i2c_port(), 0x68);
mpu6050_read_raw(&imu, &raw);

Adapters

• The adapter issues a register write followed by a repeated-start read.
• Reference: jrowberg/i2cdevlib MPU6050 (MIT), LibDriver mpu6050 (MIT), and

the InvenSense register map.

• This implementation is original.

When not to use

• A sensor with a magnetometer for absolute heading; use a 9-axis part.
• Hard real-time attitude control; use the DMP or a dedicated filter.

Verification

make test covers identity, init writes, a raw burst, scaled values, and

a wrong identity.

void *context;
uint8_t (*write)(void *context, uint8_t address, const uint8_t *data, uint16_t length);
uint8_t (*read)(void *context, uint8_t address, uint8_t *data, uint16_t length);
void (*delay_ms)(void *context, uint16_t milliseconds);

mpu6050_port_t port;
uint8_t i2c_address;

int16_t accel_x;
int16_t accel_y;
int16_t accel_z;
int16_t gyro_x;
int16_t gyro_y;
int16_t gyro_z;
int16_t temperature;

int32_t accel_x_mg;
int32_t accel_y_mg;
int32_t accel_z_mg;
int32_t gyro_x_mdps;
int32_t gyro_y_mdps;
int32_t gyro_z_mdps;
int32_t temperature_milli_celsius;