ina260: add new i2c device

ina260/ina260.go

@@ -0,0 +1,112 @@
+package ina260
+
+import "tinygo.org/x/drivers"
+
+// Device wraps an I2C connection to an INA260 device.
+type Device struct {
+	bus     drivers.I2C
+	Address uint16
+}
+
+// Config holds the configuration of the INA260 device.
+type Config struct {
+	// One of AVGMODE_XXX
+	AverageMode byte
+
+	// One of CONVTIME_XXXXUSEC
+	VoltConvTime byte
+
+	// One of CONVTIME_XXXXUSEC
+	CurrentConvTime byte
+
+	// Multiple of MODE_XXXX
+	Mode byte
+}
+
+// New creates a new INA260 connection. The I2C bus must already be
+// configured.
+//
+// This function only creates the Device object, it does not touch the device.
+func New(bus drivers.I2C) Device {
+	return Device{
+		bus:     bus,
+		Address: Address,
+	}
+}
+
+// Configure sets up the device.
+//
+// This only needs to be called to override built-in defaults. By default,
+// the device starts with:
+//
+// * AverageMode = AVGMODE_1
+// * VoltConvTime = CONVTIME_1100USEC
+// * CurrentConvTime = CONVTIME_1100USEC
+// * Mode = MODE_CONTINUOUS | MODE_VOLTAGE | MODE_CURRENT
+//
+func (d *Device) Configure(cfg Config) {
+	var val uint16
+
+	val = uint16(cfg.AverageMode&0x7) << 9
+	val |= uint16(cfg.VoltConvTime&0x7) << 6
+	val |= uint16(cfg.CurrentConvTime&0x7) << 3
+	val |= uint16(cfg.Mode & 0x7)
+
+	d.WriteRegister(REG_CONFIG, val)
+}
+
+// Resets the device, setting all registers to default values
+func (d *Device) Reset() {
+	d.WriteRegister(REG_CONFIG, 0x8000)
+}
+
+// Connected returns whether an INA260 has been found.
+func (d *Device) Connected() bool {
+	return d.ReadRegister(REG_MANF_ID) == MANF_ID &&
+		(d.ReadRegister(REG_DIE_ID)&DEVICE_ID_MASK) == DEVICE_ID
+}
+
+// Gets the measured current in µA (max resolution 1.25mA)
+func (d *Device) Current() int32 {
+	val := d.ReadRegister(REG_CURRENT)
+
+	if val&0x8000 == 0 {
+		return int32(val) * 1250
+	}
+
+	// Two's complement, convert to signed int
+	return -(int32(^val) + 1) * 1250
+}
+
+// Gets the measured voltage in µV (max resolution 1.25mV)
+func (d *Device) Voltage() int32 {
+	val := d.ReadRegister(REG_BUSVOLTAGE)
+
+	if val&0x8000 == 0 {
+		return int32(val) * 1250
+	}
+
+	// Two's complement, convert to signed int
+	return -(int32(^val) + 1) * 1250
+}
+
+// Gets the measured power in µW (max resolution 10mW)
+func (d *Device) Power() int32 {
+	return int32(d.ReadRegister(REG_POWER)) * 10000
+}
+
+// Read a register
+func (d *Device) ReadRegister(reg uint8) uint16 {
+	data := []byte{0, 0}
+	d.bus.ReadRegister(uint8(d.Address), reg, data)
+	return (uint16(data[0]) << 8) | uint16(data[1])
+}
+
+// Write to a register
+func (d *Device) WriteRegister(reg uint8, v uint16) {
+	data := []byte{0, 0}
+	data[0] = byte(v >> 8)
+	data[1] = byte(v & 0xff)
+
+	d.bus.WriteRegister(uint8(d.Address), reg, data)
+}