mag3110: add driver

mag3110/mag3110.go

@@ -0,0 +1,55 @@
+// Package mag3110 implements a driver for the MAG3110 3-axis magnetometer by
+// Freescale/NXP.
+//
+// Datasheet: https://www.nxp.com/docs/en/data-sheet/MAG3110.pdf
+package mag3110
+
+import (
+	"machine"
+)
+
+// Device wraps an I2C connection to a MAG3110 device.
+type Device struct {
+	bus machine.I2C
+}
+
+// NewI2C creates a new MAG3110 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 MAG3110 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] == 0xC4
+}
+
+// Configure sets up the device for communication.
+func (d Device) Configure() {
+	d.bus.WriteRegister(Address, CTRL_REG2, []uint8{0x80}) // Power down when not used
+}
+
+// ReadMagnetic reads the vectors of the magnetic field of the device and
+// returns it.
+func (d Device) ReadMagnetic() (x int16, y int16, z int16) {
+	d.bus.WriteRegister(Address, CTRL_REG1, []uint8{0x1a}) // Request a measurement
+
+	data := make([]byte, 6)
+	d.bus.ReadRegister(Address, OUT_X_MSB, 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
+}
+
+// ReadTemperature reads the current die temperature in degrees Celsius.
+func (d Device) ReadTemperature() (temp int8) {
+	data := make([]byte, 1)
+	d.bus.ReadRegister(Address, DIE_TEMP, data)
+	return int8(data[0])
+}