lis2mdl: better examples showing how to create unit tests

Signed-off-by: deadprogram <ron@hybridgroup.com>

lis2mdl/lis2mdl.go

@@ -1,7 +1,7 @@
 // Package lis2mdl implements a driver for the LIS2MDL,
 // a magnetic sensor which is included on BBC micro:bit v1.5.
 //
-// Datasheet: https://www.st.com/resource/en/datasheet/lsm303agr.pdf
+// Datasheet: https://www.st.com/resource/en/datasheet/lis2mdl.pdf
 //
 package lis2mdl // import "tinygo.org/x/drivers/lis2mdl"
 
@@ -33,13 +33,13 @@ type Configuration struct {
 //
 // This function only creates the Device object, it does not touch the device.
 func New(bus drivers.I2C) Device {
-	return Device{bus: bus, Address: MAG_ADDRESS}
+	return Device{bus: bus, Address: ADDRESS}
 }
 
 // Connected returns whether LIS2MDL sensor has been found.
 func (d *Device) Connected() bool {
 	data := []byte{0}
-	d.bus.ReadRegister(uint8(d.Address), MAG_WHO_AM_I, data)
+	d.bus.ReadRegister(uint8(d.Address), WHO_AM_I, data)
 	return data[0] == 0x40
 }
 
@@ -48,44 +48,44 @@ func (d *Device) Configure(cfg Configuration) {
 	if cfg.PowerMode != 0 {
 		d.PowerMode = cfg.PowerMode
 	} else {
-		d.PowerMode = MAG_POWER_NORMAL
+		d.PowerMode = POWER_NORMAL
 	}
 
 	if cfg.DataRate != 0 {
 		d.DataRate = cfg.DataRate
 	} else {
-		d.DataRate = MAG_DATARATE_100HZ
+		d.DataRate = DATARATE_100HZ
 	}
 
 	if cfg.SystemMode != 0 {
 		d.SystemMode = cfg.SystemMode
 	} else {
-		d.SystemMode = MAG_SYSTEM_CONTINUOUS
+		d.SystemMode = SYSTEM_CONTINUOUS
 	}
 
 	cmd := []byte{0}
 
 	// reset
 	cmd[0] = byte(1 << 5)
-	d.bus.WriteRegister(uint8(d.Address), MAG_MR_CFG_REG_A, cmd)
+	d.bus.WriteRegister(uint8(d.Address), CFG_REG_A, cmd)
 	time.Sleep(100 * time.Millisecond)
 
 	// reboot
 	cmd[0] = byte(1 << 6)
-	d.bus.WriteRegister(uint8(d.Address), MAG_MR_CFG_REG_A, cmd)
+	d.bus.WriteRegister(uint8(d.Address), CFG_REG_A, cmd)
 	time.Sleep(100 * time.Millisecond)
 
 	// bdu
 	cmd[0] = byte(1 << 4)
-	d.bus.WriteRegister(uint8(d.Address), MAG_MR_CFG_REG_C, cmd)
+	d.bus.WriteRegister(uint8(d.Address), CFG_REG_C, cmd)
 
 	// Temperature compensation is on for magnetic sensor (0x80)
 	cmd[0] = byte(0x80)
-	d.bus.WriteRegister(uint8(d.Address), MAG_MR_CFG_REG_A, cmd)
+	d.bus.WriteRegister(uint8(d.Address), CFG_REG_A, cmd)
 
 	// speed
 	cmd[0] = byte(0x80 | d.DataRate)
-	d.bus.WriteRegister(uint8(d.Address), MAG_MR_CFG_REG_A, cmd)
+	d.bus.WriteRegister(uint8(d.Address), CFG_REG_A, cmd)
 }
 
 // ReadMagneticField reads the current magnetic field from the device and returns
@@ -94,11 +94,11 @@ func (d *Device) ReadMagneticField() (x int32, y int32, z int32) {
 	// turn back on read mode, even though it is supposed to be continuous?
 	cmd := []byte{0}
 	cmd[0] = byte(0x80 | d.PowerMode<<4 | d.DataRate<<2 | d.SystemMode)
-	d.bus.WriteRegister(uint8(d.Address), MAG_MR_CFG_REG_A, cmd)
+	d.bus.WriteRegister(uint8(d.Address), CFG_REG_A, cmd)
 	time.Sleep(10 * time.Millisecond)
 
 	data := make([]byte, 6)
-	d.bus.ReadRegister(uint8(d.Address), MAG_OUT_X_L_M, data)
+	d.bus.ReadRegister(uint8(d.Address), OUTX_L_REG, data)
 
 	x = int32(int16((uint16(data[0]) << 8) | uint16(data[1])))
 	y = int32(int16((uint16(data[2]) << 8) | uint16(data[3])))

lis2mdl/lis2mdl_test.go

@@ -11,22 +11,49 @@ func TestDefaultI2CAddress(t *testing.T) {
 	c := qt.New(t)
 	bus := tester.NewI2CBus(c)
 	dev := New(bus)
-	c.Assert(dev.Address, qt.Equals, uint8(MAG_ADDRESS))
+	c.Assert(dev.Address, qt.Equals, uint8(ADDRESS))
 }
 
 func TestWhoAmI(t *testing.T) {
 	c := qt.New(t)
 	bus := tester.NewI2CBus(c)
-	fake := tester.NewI2CDevice(c, MAG_ADDRESS)
+	fake := tester.NewI2CDevice(c, ADDRESS)
+	fake.SetupRegisters(defaultRegisters())
 	bus.AddDevice(fake)
 
 	dev := New(bus)
-
-	fake.SetupRegisters([]uint8{
-		0x4F: 0x40,
-	})
 	c.Assert(dev.Connected(), qt.Equals, true)
 
-	fake.SetupRegister(0x4F, 0x99)
+	fake.SetupRegister(WHO_AM_I, 0x99)
 	c.Assert(dev.Connected(), qt.Equals, false)
 }
+
+// defaultRegisters returns the default values for all of the device's registers.
+// see table 22 on page 27 of the datasheet.
+func defaultRegisters() []uint8 {
+	return []uint8{
+		OFFSET_X_REG_L: 0,
+		OFFSET_X_REG_H: 0,
+		OFFSET_Y_REG_L: 0,
+		OFFSET_Y_REG_H: 0,
+		OFFSET_Z_REG_L: 0,
+		OFFSET_Z_REG_H: 0,
+		WHO_AM_I:       0x40,
+		CFG_REG_A:      0x03,
+		CFG_REG_B:      0,
+		CFG_REG_C:      0,
+		INT_CRTL_REG:   0xE0,
+		INT_SOURCE_REG: 0,
+		INT_THS_L_REG:  0,
+		INT_THS_H_REG:  0,
+		STATUS_REG:     0,
+		OUTX_L_REG:     0,
+		OUTX_H_REG:     0,
+		OUTY_L_REG:     0,
+		OUTY_H_REG:     0,
+		OUTZ_L_REG:     0,
+		OUTZ_H_REG:     0,
+		TEMP_OUT_L_REG: 0,
+		TEMP_OUT_H_REG: 0,
+	}
+}

lis2mdl/registers.go

@@ -2,31 +2,44 @@ package lis2mdl
 
 const (
 	// Constants/addresses used for I2C.
-	MAG_ADDRESS = 0x1E
+	ADDRESS = 0x1E
 
 	// magnetic sensor registers.
-	MAG_WHO_AM_I     = 0x4F
+	OFFSET_X_REG_L = 0x45
-	MAG_MR_CFG_REG_A = 0x60
+	OFFSET_X_REG_H = 0x46
-	MAG_MR_CFG_REG_B = 0x61
+	OFFSET_Y_REG_L = 0x47
-	MAG_MR_CFG_REG_C = 0x62
+	OFFSET_Y_REG_H = 0x48
-	MAG_OUT_X_L_M    = 0x68
+	OFFSET_Z_REG_L = 0x49
-	MAG_OUT_X_H_M    = 0x69
+	OFFSET_Z_REG_H = 0x4A
-	MAG_OUT_Y_L_M    = 0x6A
+	WHO_AM_I       = 0x4F
-	MAG_OUT_Y_H_M    = 0x6B
+	CFG_REG_A      = 0x60
-	MAG_OUT_Z_L_M    = 0x6C
+	CFG_REG_B      = 0x61
-	MAG_OUT_Z_H_M    = 0x6D
+	CFG_REG_C      = 0x62
+	INT_CRTL_REG   = 0x63
+	INT_SOURCE_REG = 0x64
+	INT_THS_L_REG  = 0x65
+	INT_THS_H_REG  = 0x66
+	STATUS_REG     = 0x67
+	OUTX_L_REG     = 0x68
+	OUTX_H_REG     = 0x69
+	OUTY_L_REG     = 0x6A
+	OUTY_H_REG     = 0x6B
+	OUTZ_L_REG     = 0x6C
+	OUTZ_H_REG     = 0x6D
+	TEMP_OUT_L_REG = 0x6E
+	TEMP_OUT_H_REG = 0x6F
 
 	// magnetic sensor power mode.
-	MAG_POWER_NORMAL = 0x00 // default
+	POWER_NORMAL = 0x00 // default
-	MAG_POWER_LOW    = 0x01
+	POWER_LOW    = 0x01
 
 	// magnetic sensor operate mode.
-	MAG_SYSTEM_CONTINUOUS = 0x00 // default
+	SYSTEM_CONTINUOUS = 0x00 // default
-	MAG_SYSTEM_SINGLE     = 0x01
+	SYSTEM_SINGLE     = 0x01
 
 	// magnetic sensor data rate
-	MAG_DATARATE_10HZ  = 0x00 // default
+	DATARATE_10HZ  = 0x00 // default
-	MAG_DATARATE_20HZ  = 0x01
+	DATARATE_20HZ  = 0x01
-	MAG_DATARATE_50HZ  = 0x02
+	DATARATE_50HZ  = 0x02
-	MAG_DATARATE_100HZ = 0x03
+	DATARATE_100HZ = 0x03
 )