add 4.2" with UC8276

Author: ladyada

examples/ThinkInk_tricolor/ThinkInk_tricolor.ino

@@ -23,6 +23,8 @@
 // 2.9" Tricolor Featherwing or Breakout:
 ThinkInk_290_Tricolor_Z10 display(EPD_DC, EPD_RESET, EPD_CS, SRAM_CS, EPD_BUSY);
 //ThinkInk_420_Tricolor_RW display(EPD_DC, EPD_RESET, EPD_CS, SRAM_CS, EPD_BUSY);
+//ThinkInk_420_Tricolor_Z21 display(EPD_DC, EPD_RESET, EPD_CS, SRAM_CS, EPD_BUSY);
+
 
 void setup() {
   Serial.begin(115200);

src/Adafruit_ThinkInk.h

@@ -11,6 +11,7 @@ typedef enum {
 #include "panels/ThinkInk_270_Tricolor_C44.h"
 #include "panels/ThinkInk_290_Tricolor_Z10.h"
 #include "panels/ThinkInk_420_Tricolor_RW.h"
+#include "panels/ThinkInk_420_Tricolor_Z21.h"
 
 #include "panels/ThinkInk_154_Grayscale4_T8.h"
 #include "panels/ThinkInk_213_Grayscale4_T5.h"

src/drivers/Adafruit_UC8276.h

@@ -17,32 +17,6 @@
 #define UC8276_WRITE_VCOM 0x50
 #define UC8276_GET_STATUS 0x71
 
-/*
-#define UC8276_GATE_VOLTAGE 0x03
-#define UC8276_PROGOTP_INITIAL 0x08
-#define UC8276_PROGREG_INITIAL 0x09
-#define UC8276_READREG_INITIAL 0x0A
-#define UC8276_BOOST_SOFTSTART 0x0C
-#define UC8276_DATA_MODE 0x11
-#define UC8276_SW_RESET 0x12
-#define UC8276_TEMP_CONTROL 0x18
-#define UC8276_TEMP_WRITE 0x1A
-
-#define UC8276_DISP_CTRL1 0x21
-#define UC8276_DISP_CTRL2 0x22
-
-#define UC8276_READ_OTP 0x2D
-#define UC8276_READ_STATUS 0x2F
-#define UC8276_WRITE_LUT 0x32
-#define UC8276_WRITE_BORDER 0x3C
-#define UC8276_SET_RAMXPOS 0x44
-#define UC8276_SET_RAMYPOS 0x45
-#define UC8276_SET_RAMXCOUNT 0x4E
-#define UC8276_SET_RAMYCOUNT 0x4F
-#define UC8276_SET_ANALOGBLOCK 0x74
-#define UC8276_SET_DIGITALBLOCK 0x7E
-*/
-
 /**************************************************************************/
 /*!
     @brief  Class for interfacing with UC8276 EPD drivers

src/panels/ThinkInk_420_Tricolor_Z21.h

@@ -0,0 +1,36 @@
+#ifndef _THINKINK_420_TRICOLOR_Z21_H
+#define _THINKINK_420_TRICOLOR_Z21_H
+
+#include "Adafruit_EPD.h"
+
+class ThinkInk_420_Tricolor_Z21 : public Adafruit_UC8276 {
+private:
+public:
+  ThinkInk_420_Tricolor_Z21(int8_t SID, int8_t SCLK, int8_t DC, int8_t RST,
+                           int8_t CS, int8_t SRCS, int8_t MISO,
+                           int8_t BUSY = -1)
+      : Adafruit_UC8276(300, 400, SID, SCLK, DC, RST, CS, SRCS, MISO, BUSY){};
+
+  ThinkInk_420_Tricolor_Z21(int8_t DC, int8_t RST, int8_t CS, int8_t SRCS,
+                           int8_t BUSY = -1, SPIClass *spi = &SPI)
+      : Adafruit_UC8276(300, 400, DC, RST, CS, SRCS, BUSY, spi){};
+
+  void begin(thinkinkmode_t mode = THINKINK_TRICOLOR) {
+    Adafruit_EPD::begin(true);
+    setBlackBuffer(0, true);
+    setColorBuffer(1, false);
+
+    layer_colors[EPD_WHITE] = 0b00;
+    layer_colors[EPD_BLACK] = 0b01;
+    layer_colors[EPD_RED] = 0b10;
+    layer_colors[EPD_GRAY] = 0b10;
+    layer_colors[EPD_LIGHT] = 0b00;
+    layer_colors[EPD_DARK] = 0b01;
+
+    default_refresh_delay = 13000;
+    setRotation(1);
+    powerDown();
+  };
+};
+
+#endif // _THINKINK_420_TRI