waveshare213v2: Document more values

Introduce named constants where possible (based on the data sheet) and
compute values instead of using hardcoded ones.

Signed-off-by: Michael Hanselmann <public@hansmi.ch>

waveshare2in13v2/waveshare213v2.go

@@ -46,6 +46,15 @@ const (
 	setDigitalBlockControl         byte = 0x7E
 )
 
+// Register values
+const (
+	gateDrivingVoltage19V = 0x15
+
+	sourceDrivingVoltageVSH1_15V   = 0x41
+	sourceDrivingVoltageVSH2_5V    = 0xA8
+	sourceDrivingVoltageVSL_neg15V = 0x32
+)
+
 // Dev defines the handler which is used to access the display.
 type Dev struct {
 	c conn.Conn
@@ -90,38 +99,34 @@ var EPD2in13v2 = Opts{
 	Width:  122,
 	Height: 250,
 	FullUpdate: LUT{
-		0x80, 0x60, 0x40, 0x00, 0x00, 0x00, 0x00,
-		0x10, 0x60, 0x20, 0x00, 0x00, 0x00, 0x00,
-		0x80, 0x60, 0x40, 0x00, 0x00, 0x00, 0x00,
-		0x10, 0x60, 0x20, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-
-		0x03, 0x03, 0x00, 0x00, 0x02,
-		0x09, 0x09, 0x00, 0x00, 0x02,
-		0x03, 0x03, 0x00, 0x00, 0x02,
-		0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00,
-
-		0x15, 0x41, 0xA8, 0x32, 0x30, 0x0A,
+		0x80, 0x60, 0x40, 0x00, 0x00, 0x00, 0x00, //LUT0: BB:     VS 0 ~7
+		0x10, 0x60, 0x20, 0x00, 0x00, 0x00, 0x00, //LUT1: BW:     VS 0 ~7
+		0x80, 0x60, 0x40, 0x00, 0x00, 0x00, 0x00, //LUT2: WB:     VS 0 ~7
+		0x10, 0x60, 0x20, 0x00, 0x00, 0x00, 0x00, //LUT3: WW:     VS 0 ~7
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //LUT4: VCOM:   VS 0 ~7
+
+		0x03, 0x03, 0x00, 0x00, 0x02, // TP0 A~D RP0
+		0x09, 0x09, 0x00, 0x00, 0x02, // TP1 A~D RP1
+		0x03, 0x03, 0x00, 0x00, 0x02, // TP2 A~D RP2
+		0x00, 0x00, 0x00, 0x00, 0x00, // TP3 A~D RP3
+		0x00, 0x00, 0x00, 0x00, 0x00, // TP4 A~D RP4
+		0x00, 0x00, 0x00, 0x00, 0x00, // TP5 A~D RP5
+		0x00, 0x00, 0x00, 0x00, 0x00, // TP6 A~D RP6
 	},
 	PartialUpdate: LUT{
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-		0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-		0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
-
-		0x0A, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00,
-		0x00, 0x00, 0x00, 0x00, 0x00,
-
-		0x15, 0x41, 0xA8, 0x32, 0x30, 0x0A,
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //LUT0: BB:     VS 0 ~7
+		0x80, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //LUT1: BW:     VS 0 ~7
+		0x40, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //LUT2: WB:     VS 0 ~7
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //LUT3: WW:     VS 0 ~7
+		0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, //LUT4: VCOM:   VS 0 ~7
+
+		0x0A, 0x00, 0x00, 0x00, 0x00, // TP0 A~D RP0
+		0x00, 0x00, 0x00, 0x00, 0x00, // TP1 A~D RP1
+		0x00, 0x00, 0x00, 0x00, 0x00, // TP2 A~D RP2
+		0x00, 0x00, 0x00, 0x00, 0x00, // TP3 A~D RP3
+		0x00, 0x00, 0x00, 0x00, 0x00, // TP4 A~D RP4
+		0x00, 0x00, 0x00, 0x00, 0x00, // TP5 A~D RP5
+		0x00, 0x00, 0x00, 0x00, 0x00, // TP6 A~D RP6
 	},
 }
 
@@ -221,9 +226,7 @@ func (d *Dev) Init(partialUpdate PartialUpdate) error {
 		d.waitUntilIdle()
 
 		eh.sendCommand([]byte{writeLutRegister})
-		for i := range [70]int{} {
-			eh.sendData([]byte{d.opts.PartialUpdate[i]})
-		}
+		eh.sendData(d.opts.PartialUpdate[:70])
 
 		eh.sendCommand([]byte{0x37})
 		eh.sendData([]byte{0x00, 0x00, 0x00, 0x00, 0x40, 0x00, 0x00})
@@ -257,7 +260,11 @@ func (d *Dev) Init(partialUpdate PartialUpdate) error {
 
 		// Driver output control
 		eh.sendCommand([]byte{driverOutputControl})
-		eh.sendData([]byte{0xF9, 0x00, 0x00})
+		eh.sendData([]byte{
+			byte((d.opts.Height - 1) % 0xFF),
+			byte((d.opts.Height - 1) / 0xFF),
+			0x00,
+		})
 
 		// Data entry mode
 		eh.sendCommand([]byte{dataEntryModeSetting})
@@ -280,23 +287,21 @@ func (d *Dev) Init(partialUpdate PartialUpdate) error {
 		eh.sendData([]byte{0x55})
 
 		eh.sendCommand([]byte{gateDrivingVoltageControl})
-		eh.sendData([]byte{d.opts.FullUpdate[70]})
+		eh.sendData([]byte{gateDrivingVoltage19V})
 
 		eh.sendCommand([]byte{sourceDrivingVoltageControl})
-		eh.sendData([]byte{d.opts.FullUpdate[71], d.opts.FullUpdate[72], d.opts.FullUpdate[73]})
+		eh.sendData([]byte{sourceDrivingVoltageVSH1_15V, sourceDrivingVoltageVSH2_5V, sourceDrivingVoltageVSL_neg15V})
 
 		// Dummy Line
 		eh.sendCommand([]byte{setDummyLinePeriod})
-		eh.sendData([]byte{d.opts.FullUpdate[74]})
+		eh.sendData([]byte{0x30})
 
 		// Gate Time
 		eh.sendCommand([]byte{setGateTime})
-		eh.sendData([]byte{d.opts.FullUpdate[75]})
+		eh.sendData([]byte{0x0A})
 
 		eh.sendCommand([]byte{writeLutRegister})
-		for i := range [70]int{} {
-			eh.sendData([]byte{d.opts.FullUpdate[i]})
-		}
+		eh.sendData(d.opts.FullUpdate[:70])
 
 		// Set RAM x address count to 0
 		eh.sendCommand([]byte{setRAMXAddressCounter})