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)
+}

ina260/ina260_test.go

@@ -0,0 +1,80 @@
+package ina260
+
+import (
+	"testing"
+
+	qt "github.com/frankban/quicktest"
+	"tinygo.org/x/drivers/tester"
+)
+
+func TestDefaultI2CAddress(t *testing.T) {
+	c := qt.New(t)
+	bus := tester.NewI2CBus(c)
+	dev := New(bus)
+	c.Assert(dev.Address, qt.Equals, uint16(Address))
+}
+
+func TestConnected(t *testing.T) {
+	c := qt.New(t)
+	bus := tester.NewI2CBus(c)
+	fake := tester.NewI2CDevice16(c, Address)
+	fake.Registers = defaultRegisters()
+	bus.AddDevice(fake)
+
+	dev := New(bus)
+	c.Assert(dev.Connected(), qt.Equals, true)
+}
+
+func TestVoltage(t *testing.T) {
+	c := qt.New(t)
+	bus := tester.NewI2CBus(c)
+	fake := tester.NewI2CDevice16(c, Address)
+	fake.Registers = defaultRegisters()
+	fake.Registers[REG_BUSVOLTAGE] = 0x2570
+	bus.AddDevice(fake)
+
+	dev := New(bus)
+	// Datasheet: 2570h = 11.98V = 11980mV = 11980000uV
+	c.Assert(dev.Voltage(), qt.Equals, int32(11980000))
+}
+
+func TestCurrent(t *testing.T) {
+	c := qt.New(t)
+	bus := tester.NewI2CBus(c)
+	fake := tester.NewI2CDevice16(c, Address)
+	fake.Registers = defaultRegisters()
+	fake.Registers[REG_CURRENT] = 0x2710
+	bus.AddDevice(fake)
+
+	dev := New(bus)
+	// Datasheet: 2710h = 12.5A = 12500mA = 12500000uA
+	c.Assert(dev.Current(), qt.Equals, int32(12500000))
+}
+
+func TestPower(t *testing.T) {
+	c := qt.New(t)
+	bus := tester.NewI2CBus(c)
+	fake := tester.NewI2CDevice16(c, Address)
+	fake.Registers = defaultRegisters()
+	fake.Registers[REG_POWER] = 0x3A7F
+	bus.AddDevice(fake)
+
+	dev := New(bus)
+	// 3A7Fh = 149.75W = 149750mW = 149750000uW
+	c.Assert(dev.Power(), qt.Equals, int32(149750000))
+}
+
+// defaultRegisters returns the default values for all of the device's registers.
+// set TI INA260 datasheet for power-on defaults
+func defaultRegisters() map[uint8]uint16 {
+	return map[uint8]uint16{
+		REG_CONFIG:     0x6127,
+		REG_CURRENT:    0x0000,
+		REG_BUSVOLTAGE: 0x0000,
+		REG_POWER:      0x0000,
+		REG_MASKENABLE: 0x0000,
+		REG_ALERTLIMIT: 0x0000,
+		REG_MANF_ID:    0x5449,
+		REG_DIE_ID:     0x2270,
+	}
+}

ina260/registers.go

@@ -0,0 +1,50 @@
+package ina260
+
+// The default I2C address for this device.
+//
+// The actual address is configurable by connecting address pins.
+const Address = 0x40
+
+// Registers
+const (
+	REG_CONFIG     = 0x00
+	REG_CURRENT    = 0x01
+	REG_BUSVOLTAGE = 0x02
+	REG_POWER      = 0x03
+	REG_MASKENABLE = 0x06
+	REG_ALERTLIMIT = 0x07
+	REG_MANF_ID    = 0xFE
+	REG_DIE_ID     = 0xFF
+)
+
+// Well-Known Values
+const (
+	MANF_ID        = 0x5449 // TI
+	DEVICE_ID      = 0x2270 // 227h
+	DEVICE_ID_MASK = 0xFFF0
+
+	AVGMODE_1    = 0
+	AVGMODE_4    = 1
+	AVGMODE_16   = 2
+	AVGMODE_64   = 3
+	AVGMODE_128  = 4
+	AVGMODE_256  = 5
+	AVGMODE_512  = 6
+	AVGMODE_1024 = 7
+
+	CONVTIME_140USEC  = 0
+	CONVTIME_204USEC  = 1
+	CONVTIME_332USEC  = 2
+	CONVTIME_588USEC  = 3
+	CONVTIME_1100USEC = 4 // 1.1 ms
+	CONVTIME_2116USEC = 5 // 2.1 ms
+	CONVTIME_4156USEC = 6 // 4.2 ms
+	CONVTIME_8244USEC = 7 // 8.2 ms
+
+	MODE_CONTINUOUS = 0x4
+	MODE_TRIGGERED  = 0x0
+	MODE_VOLTAGE    = 0x2
+	MODE_NO_VOLTAGE = 0x0
+	MODE_CURRENT    = 0x1
+	MODE_NO_CURRENT = 0x0
+)