mirror of
https://github.com/tinygo-org/drivers.git
synced 2026-08-19 06:03:57 +00:00
Ayke van Laethem
6763521eff
This type should be used whenever a sensor (or actuator?) works with a
temperature. For example, this commit changes the signature:
ReadTemperature() (int32, error)
to the following:
ReadTemperature() (drivers.Temperature, error)
I believe this is much clearer in intent. It also makes it trivial to
introduce common conversions. For example, there are already Celsius()
and Fahrenheit() methods to convert to the given units, as a floating
point. More units could be added as needed, for example a CelsiusInt().
205 lines
6.8 KiB
Go
205 lines
6.8 KiB
Go
// Package lsm303agr implements a driver for the LSM303AGR,
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// a 3 axis accelerometer/magnetic sensor which is included on BBC micro:bits v1.5.
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//
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// Datasheet: https://www.st.com/resource/en/datasheet/lsm303agr.pdf
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//
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package lsm303agr // import "tinygo.org/x/drivers/lsm303agr"
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import (
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"math"
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"tinygo.org/x/drivers"
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)
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// Device wraps an I2C connection to a LSM303AGR device.
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type Device struct {
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bus drivers.I2C
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AccelAddress uint8
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MagAddress uint8
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AccelPowerMode uint8
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AccelRange uint8
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AccelDataRate uint8
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MagPowerMode uint8
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MagSystemMode uint8
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MagDataRate uint8
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}
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// Configuration for LSM303AGR device.
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type Configuration struct {
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AccelPowerMode uint8
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AccelRange uint8
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AccelDataRate uint8
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MagPowerMode uint8
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MagSystemMode uint8
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MagDataRate uint8
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}
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// New creates a new LSM303AGR connection. The I2C bus must already be
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// configured.
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//
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// This function only creates the Device object, it does not touch the device.
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func New(bus drivers.I2C) Device {
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return Device{bus: bus, AccelAddress: ACCEL_ADDRESS, MagAddress: MAG_ADDRESS}
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}
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// Connected returns whether both sensor on LSM303AGR has been found.
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// It does two "who am I" requests and checks the responses.
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func (d *Device) Connected() bool {
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data1, data2 := []byte{0}, []byte{0}
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d.bus.ReadRegister(uint8(d.AccelAddress), ACCEL_WHO_AM_I, data1)
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d.bus.ReadRegister(uint8(d.MagAddress), MAG_WHO_AM_I, data2)
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return data1[0] == 0x33 && data2[0] == 0x40
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}
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// Configure sets up the LSM303AGR device for communication.
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func (d *Device) Configure(cfg Configuration) {
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if cfg.AccelDataRate != 0 {
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d.AccelDataRate = cfg.AccelDataRate
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} else {
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d.AccelDataRate = ACCEL_DATARATE_100HZ
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}
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if cfg.AccelPowerMode != 0 {
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d.AccelPowerMode = cfg.AccelPowerMode
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} else {
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d.AccelPowerMode = ACCEL_POWER_NORMAL
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}
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if cfg.AccelRange != 0 {
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d.AccelRange = cfg.AccelRange
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} else {
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d.AccelRange = ACCEL_RANGE_2G
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}
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if cfg.MagPowerMode != 0 {
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d.MagPowerMode = cfg.MagPowerMode
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} else {
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d.MagPowerMode = MAG_POWER_NORMAL
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}
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if cfg.MagDataRate != 0 {
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d.MagDataRate = cfg.MagDataRate
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} else {
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d.MagDataRate = MAG_DATARATE_10HZ
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}
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if cfg.MagSystemMode != 0 {
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d.MagSystemMode = cfg.MagSystemMode
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} else {
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d.MagSystemMode = MAG_SYSTEM_CONTINUOUS
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}
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cmd := []byte{0}
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cmd[0] = byte(d.AccelDataRate<<4 | d.AccelPowerMode | 0x07)
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d.bus.WriteRegister(uint8(d.AccelAddress), ACCEL_CTRL_REG1_A, cmd)
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cmd[0] = byte(0x80 | d.AccelRange<<4)
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d.bus.WriteRegister(uint8(d.AccelAddress), ACCEL_CTRL_REG4_A, cmd)
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cmd[0] = byte(0xC0)
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d.bus.WriteRegister(uint8(d.AccelAddress), TEMP_CFG_REG_A, cmd)
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// Temperature compensation is on for magnetic sensor
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cmd[0] = byte(0x80 | d.MagPowerMode<<4 | d.MagDataRate<<2 | d.MagSystemMode)
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d.bus.WriteRegister(uint8(d.MagAddress), MAG_MR_REG_M, cmd)
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}
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// ReadAcceleration reads the current acceleration from the device and returns
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// it in µg (micro-gravity). When one of the axes is pointing straight to Earth
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// and the sensor is not moving the returned value will be around 1000000 or
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// -1000000.
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func (d *Device) ReadAcceleration() (x int32, y int32, z int32) {
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data1, data2, data3, data4, data5, data6 := []byte{0}, []byte{0}, []byte{0}, []byte{0}, []byte{0}, []byte{0}
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d.bus.ReadRegister(uint8(d.AccelAddress), ACCEL_OUT_X_H_A, data1)
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d.bus.ReadRegister(uint8(d.AccelAddress), ACCEL_OUT_X_L_A, data2)
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d.bus.ReadRegister(uint8(d.AccelAddress), ACCEL_OUT_Y_H_A, data3)
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d.bus.ReadRegister(uint8(d.AccelAddress), ACCEL_OUT_Y_L_A, data4)
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d.bus.ReadRegister(uint8(d.AccelAddress), ACCEL_OUT_Z_H_A, data5)
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d.bus.ReadRegister(uint8(d.AccelAddress), ACCEL_OUT_Z_L_A, data6)
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rangeFactor := int16(0)
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switch d.AccelRange {
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case ACCEL_RANGE_2G:
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rangeFactor = 1
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case ACCEL_RANGE_4G:
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rangeFactor = 2
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case ACCEL_RANGE_8G:
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rangeFactor = 4
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case ACCEL_RANGE_16G:
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rangeFactor = 12 // the readings in 16G are a bit lower
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}
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x = int32(int32(int16((uint16(data1[0])<<8|uint16(data2[0])))>>4*rangeFactor) * 1000000 / 1024)
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y = int32(int32(int16((uint16(data3[0])<<8|uint16(data4[0])))>>4*rangeFactor) * 1000000 / 1024)
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z = int32(int32(int16((uint16(data5[0])<<8|uint16(data6[0])))>>4*rangeFactor) * 1000000 / 1024)
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return
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}
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// ReadPitchRoll reads the current pitch and roll angles from the device and
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// returns it in micro-degrees. When the z axis is pointing straight to Earth
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// the returned values of pitch and roll would be zero.
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func (d *Device) ReadPitchRoll() (pitch int32, roll int32) {
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x, y, z := d.ReadAcceleration()
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xf, yf, zf := float64(x), float64(y), float64(z)
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pitch = int32((math.Round(math.Atan2(yf, math.Sqrt(math.Pow(xf, 2)+math.Pow(zf, 2)))*(180/math.Pi)*100) / 100) * 1000000)
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roll = int32((math.Round(math.Atan2(xf, math.Sqrt(math.Pow(yf, 2)+math.Pow(zf, 2)))*(180/math.Pi)*100) / 100) * 1000000)
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return
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}
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// ReadMagneticField reads the current magnetic field from the device and returns
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// it in mG (milligauss). 1 mG = 0.1 µT (microtesla).
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func (d *Device) ReadMagneticField() (x int32, y int32, z int32) {
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if d.MagSystemMode == MAG_SYSTEM_SINGLE {
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cmd := []byte{0}
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cmd[0] = byte(0x80 | d.MagPowerMode<<4 | d.MagDataRate<<2 | d.MagSystemMode)
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d.bus.WriteRegister(uint8(d.MagAddress), MAG_MR_REG_M, cmd)
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}
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data1, data2, data3, data4, data5, data6 := []byte{0}, []byte{0}, []byte{0}, []byte{0}, []byte{0}, []byte{0}
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d.bus.ReadRegister(uint8(d.MagAddress), MAG_OUT_X_H_M, data1)
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d.bus.ReadRegister(uint8(d.MagAddress), MAG_OUT_X_L_M, data2)
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d.bus.ReadRegister(uint8(d.MagAddress), MAG_OUT_Y_H_M, data3)
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d.bus.ReadRegister(uint8(d.MagAddress), MAG_OUT_Y_L_M, data4)
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d.bus.ReadRegister(uint8(d.MagAddress), MAG_OUT_Z_H_M, data5)
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d.bus.ReadRegister(uint8(d.MagAddress), MAG_OUT_Z_L_M, data6)
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x = int32(int16((uint16(data1[0])<<8 | uint16(data2[0]))))
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y = int32(int16((uint16(data3[0])<<8 | uint16(data4[0]))))
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z = int32(int16((uint16(data5[0])<<8 | uint16(data6[0]))))
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return
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}
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// ReadCompass reads the current compass heading from the device and returns
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// it in micro-degrees. When the z axis is pointing straight to Earth and
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// the y axis is pointing to North, the heading would be zero.
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//
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// However, the heading may be off due to electronic compasses would be effected
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// by strong magnetic fields and require constant calibration.
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func (d *Device) ReadCompass() (h int32) {
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x, y, _ := d.ReadMagneticField()
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xf, yf := float64(x), float64(y)
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h = int32(float32((180/math.Pi)*math.Atan2(yf, xf)) * 1000000)
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return
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}
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// ReadTemperature returns the temperature in Celsius milli degrees (°C/1000)
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func (d *Device) ReadTemperature() (c drivers.Temperature, e error) {
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data1, data2 := []byte{0}, []byte{0}
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d.bus.ReadRegister(uint8(d.AccelAddress), OUT_TEMP_H_A, data1)
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d.bus.ReadRegister(uint8(d.AccelAddress), OUT_TEMP_L_A, data2)
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t := int16((uint16(data1[0])<<8 | uint16(data2[0]))) >> 4 // temperature offsef from 25 °C
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c = drivers.Temperature(t)*125 + 25000
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e = nil
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return
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}
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