Basic implementation of various backlight drivers

backlight/PWM.go

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+package backlight
+
+import "machine"
+
+type PWM interface {
+	Configure(config machine.PWMConfig) error
+	Channel(pin machine.Pin) (channel uint8, err error)
+	Top() uint32
+	Set(channel uint8, value uint32)
+}
+
+type PWMDriver struct {
+	pwm PWM
+	ch  uint8
+}
+
+func NewPWMDriver(pwm PWM, pin machine.Pin) (PWMDriver, error) {
+	err := pwm.Configure(machine.PWMConfig{})
+	if err != nil {
+		return PWMDriver{}, err
+	}
+	ch, err := pwm.Channel(pin)
+	if err != nil {
+		return PWMDriver{}, err
+	}
+	return PWMDriver{pwm, ch}, nil
+}
+
+func (b PWMDriver) SetBrightness(brightness uint8) {
+	b.pwm.Set(b.ch, b.pwm.Top()*uint32(brightness)/255)
+}

backlight/backlight.go

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+package backlight
+
+type Driver interface {
+	SetBrightness(uint8)
+}

backlight/onoff.go

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+package backlight
+
+import "machine"
+
+type OnOffDriver struct {
+	blPin machine.Pin
+}
+
+func NewOnOffDriver(pin machine.Pin) OnOffDriver {
+	pin.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	return OnOffDriver{blPin: pin}
+}
+
+func (b OnOffDriver) SetBrightness(brightness uint8) {
+	if brightness < 128 {
+		b.blPin.Low()
+	} else {
+		b.blPin.High()
+	}
+}

backlight/pinetime.go

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+package backlight
+
+import "machine"
+
+type PineTimeDriver struct {
+	blLowPin  machine.Pin
+	blMidPin  machine.Pin
+	blHighPin machine.Pin
+}
+
+func NewPineTimeDriver(lowPin, midPin, highPin machine.Pin) PineTimeDriver {
+	lowPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	midPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	highPin.Configure(machine.PinConfig{Mode: machine.PinOutput})
+	return PineTimeDriver{blLowPin: lowPin, blMidPin: midPin, blHighPin: highPin}
+}
+
+// Not sure if you can combine the three pins to get intermediate brightness levels.s
+func (b PineTimeDriver) SetBrightness(brightness uint8) {
+	if brightness < 85 {
+		b.blLowPin.Low()
+		b.blMidPin.High()
+		b.blHighPin.High()
+	} else if brightness < 170 {
+		b.blLowPin.High()
+		b.blMidPin.Low()
+		b.blHighPin.High()
+	} else {
+		b.blLowPin.High()
+		b.blMidPin.High()
+		b.blHighPin.Low()
+	}
+}