mpu6050: add driver

Only the accelerometer is supported at the moment.

mpu6050/mpu6050.go

@@ -0,0 +1,48 @@
+// Package mpu6050 provides a driver for the MPU6050 accelerometer and gyroscope
+// made by InvenSense.
+//
+// Datasheets:
+// https://store.invensense.com/datasheets/invensense/MPU-6050_DataSheet_V3%204.pdf
+// https://www.invensense.com/wp-content/uploads/2015/02/MPU-6000-Register-Map1.pdf
+package mpu6050
+
+import (
+	"machine"
+)
+
+// Device wraps an I2C connection to a MPU6050 device.
+type Device struct {
+	bus machine.I2C
+}
+
+// NewI2C creates a new MPU6050 connection. The I2C bus must already be
+// configured.
+//
+// This function only creates the Device object, it does not touch the device.
+func NewI2C(bus machine.I2C) Device {
+	return Device{bus}
+}
+
+// Connected returns whether a MPU6050 has been found.
+// It does a "who am I" request and checks the response.
+func (d Device) Connected() bool {
+	data := []byte{0}
+	d.bus.ReadRegister(Address, WHO_AM_I, data)
+	return data[0] == 0x68
+}
+
+// Configure sets up the device for communication.
+func (d Device) Configure() {
+	d.bus.WriteRegister(Address, PWR_MGMT_1, []uint8{0})
+}
+
+// ReadAcceleration reads the current acceleration from the device and returns
+// it.
+func (d Device) ReadAcceleration() (x int16, y int16, z int16) {
+	data := make([]byte, 6)
+	d.bus.ReadRegister(Address, ACCEL_XOUT_H, data)
+	x = int16((uint16(data[0]) << 8) | uint16(data[1]))
+	y = int16((uint16(data[2]) << 8) | uint16(data[3]))
+	z = int16((uint16(data[4]) << 8) | uint16(data[5]))
+	return
+}

mpu6050/registers.go

@@ -0,0 +1,109 @@
+package mpu6050
+
+// Constants/addresses used for I2C.
+
+// The I2C address which this device listens to.
+const Address = 0x68
+
+// Registers. Names, addresses and comments copied from the datasheet.
+const (
+	// Self test registers
+	SELF_TEST_X = 0x0D
+	SELF_TEST_Y = 0x0E
+	SELF_TEST_Z = 0x0F
+	SELF_TEST_A = 0x10
+
+	SMPLRT_DIV   = 0x19 // Sample rate divider
+	CONFIG       = 0x1A // Configuration
+	GYRO_CONFIG  = 0x1B // Gyroscope configuration
+	ACCEL_CONFIG = 0x1C // Accelerometer configuration
+	FIFO_EN      = 0x23 // FIFO enable
+
+	// I2C pass-through configuration
+	I2C_MST_CTRL   = 0x24
+	I2C_SLV0_ADDR  = 0x25
+	I2C_SLV0_REG   = 0x26
+	I2C_SLV0_CTRL  = 0x27
+	I2C_SLV1_ADDR  = 0x28
+	I2C_SLV1_REG   = 0x29
+	I2C_SLV1_CTRL  = 0x2A
+	I2C_SLV2_ADDR  = 0x2B
+	I2C_SLV2_REG   = 0x2C
+	I2C_SLV2_CTRL  = 0x2D
+	I2C_SLV3_ADDR  = 0x2E
+	I2C_SLV3_REG   = 0x2F
+	I2C_SLV3_CTRL  = 0x30
+	I2C_SLV4_ADDR  = 0x31
+	I2C_SLV4_REG   = 0x32
+	I2C_SLV4_DO    = 0x33
+	I2C_SLV4_CTRL  = 0x34
+	I2C_SLV4_DI    = 0x35
+	I2C_MST_STATUS = 0x36
+
+	// Interrupt configuration
+	INT_PIN_CFG = 0x37 // Interrupt pin/bypass enable configuration
+	INT_ENABLE  = 0x38 // Interrupt enable
+	INT_STATUS  = 0x3A // Interrupt status
+
+	// Accelerometer measurements
+	ACCEL_XOUT_H = 0x3B
+	ACCEL_XOUT_L = 0x3C
+	ACCEL_YOUT_H = 0x3D
+	ACCEL_YOUT_L = 0x3E
+	ACCEL_ZOUT_H = 0x3F
+	ACCEL_ZOUT_L = 0x40
+
+	// Temperature measurement
+	TEMP_OUT_H = 0x41
+	TEMP_OUT_L = 0x42
+
+	// Gyroscope measurements
+	GYRO_XOUT_H = 0x43
+	GYRO_XOUT_L = 0x44
+	GYRO_YOUT_H = 0x45
+	GYRO_YOUT_L = 0x46
+	GYRO_ZOUT_H = 0x47
+	GYRO_ZOUT_L = 0x48
+
+	// External sensor data
+	EXT_SENS_DATA_00 = 0x49
+	EXT_SENS_DATA_01 = 0x4A
+	EXT_SENS_DATA_02 = 0x4B
+	EXT_SENS_DATA_03 = 0x4C
+	EXT_SENS_DATA_04 = 0x4D
+	EXT_SENS_DATA_05 = 0x4E
+	EXT_SENS_DATA_06 = 0x4F
+	EXT_SENS_DATA_07 = 0x50
+	EXT_SENS_DATA_08 = 0x51
+	EXT_SENS_DATA_09 = 0x52
+	EXT_SENS_DATA_10 = 0x53
+	EXT_SENS_DATA_11 = 0x54
+	EXT_SENS_DATA_12 = 0x55
+	EXT_SENS_DATA_13 = 0x56
+	EXT_SENS_DATA_14 = 0x57
+	EXT_SENS_DATA_15 = 0x58
+	EXT_SENS_DATA_16 = 0x59
+	EXT_SENS_DATA_17 = 0x5A
+	EXT_SENS_DATA_18 = 0x5B
+	EXT_SENS_DATA_19 = 0x5C
+	EXT_SENS_DATA_20 = 0x5D
+	EXT_SENS_DATA_21 = 0x5E
+	EXT_SENS_DATA_22 = 0x5F
+	EXT_SENS_DATA_23 = 0x60
+
+	// I2C slave data out
+	I2C_SLV0_DO      = 0x63
+	I2C_SLV1_DO      = 0x64
+	I2C_SLV2_DO      = 0x65
+	I2C_SLV3_DO      = 0x66
+	I2C_MST_DELAY_CT = 0x67
+
+	SIGNAL_PATH_RES = 0x68 // Signal path reset
+	USER_CTRL       = 0x6A // User control
+	PWR_MGMT_1      = 0x6B // Power Management 1
+	PWR_MGMT_2      = 0x6C // Power Management 2
+	FIFO_COUNTH     = 0x72 // FIFO count registers (high bits)
+	FIFO_COUNTL     = 0x73 // FIFO count registers (low bits)
+	FIFO_R_W        = 0x74 // FIFO read/write
+	WHO_AM_I        = 0x75 // Who am I
+)