add 1.54" epd ssd1681 grayscale support

examples/ThinkInk_gray4/ThinkInk_gray4.ino

@@ -30,6 +30,10 @@
 // EPD_BUSY, EPD_SPI); ThinkInk_213_Grayscale4_T5 display(EPD_DC, EPD_RESET,
 // EPD_CS, SRAM_CS, EPD_BUSY, EPD_SPI);
 
+// 1.54" Grayscale Breakout (SSD1681)
+//ThinkInk_154_Grayscale4_M05 display(EPD_DC, EPD_RESET, EPD_CS, SRAM_CS, EPD_BUSY,
+//                                    EPD_SPI);
+
 // 2.13" Grayscale Featherwing or Breakout (SSD1680Z)
 ThinkInk_213_Grayscale4_MFGN display(EPD_DC, EPD_RESET, EPD_CS, SRAM_CS, EPD_BUSY,
                                      EPD_SPI);

src/Adafruit_EPD.cpp

@@ -509,7 +509,7 @@ void Adafruit_EPD::clearDisplay() {
  */
 /**************************************************************************/
 void Adafruit_EPD::EPD_commandList(const uint8_t* init_code) {
-  uint8_t buf[255];
+  uint8_t buf[250];
 
   while (init_code[0] != 0xFE) {
     uint8_t cmd = init_code[0];

src/Adafruit_ThinkInk.h

@@ -6,6 +6,7 @@
 #include "panels/ThinkInk_154_Mono_D27.h"
 #include "panels/ThinkInk_154_Mono_D67.h"
 #include "panels/ThinkInk_154_Mono_M10.h"
+#include "panels/ThinkInk_154_Grayscale4_M05.h"
 #include "panels/ThinkInk_154_Tricolor_RW.h"
 #include "panels/ThinkInk_154_Tricolor_Z17.h"
 #include "panels/ThinkInk_154_Tricolor_Z90.h"

src/drivers/Adafruit_JD79661.cpp

@@ -256,7 +256,6 @@ void Adafruit_JD79661::hardwareReset(void) {
 /**************************************************************************/
 
 void Adafruit_JD79661::powerUp() {
-  uint8_t buf[5];
   hardwareReset();
   busy_wait();
 

src/drivers/Adafruit_SSD1680.cpp

@@ -49,7 +49,7 @@ Adafruit_SSD1680::Adafruit_SSD1680(int width, int height, int16_t SID,
     height += 8 - (height % 8);
   }
 
-  buffer1_size = width * height / 8;
+  buffer1_size = ((uint32_t)width * (uint32_t)height) / 8;
   buffer2_size = buffer1_size;
 
   if (SRCS >= 0) {
@@ -87,7 +87,7 @@ Adafruit_SSD1680::Adafruit_SSD1680(int width, int height, int16_t DC,
     height += 8 - (height % 8);
   }
 
-  buffer1_size = width * height / 8;
+  buffer1_size = ((uint32_t)width * (uint32_t)height) / 8;
   buffer2_size = buffer1_size;
 
   if (SRCS >= 0) {

src/drivers/Adafruit_SSD1681.cpp

@@ -136,7 +136,7 @@ void Adafruit_SSD1681::update() {
   uint8_t buf[1];
 
   // display update sequence
-  buf[0] = 0xF7;
+  buf[0] = _display_update_val;  // varies for mono vs gray4 mode
   EPD_command(SSD1681_DISP_CTRL2, buf, 1);
 
   EPD_command(SSD1681_MASTER_ACTIVATE);
@@ -267,13 +267,20 @@ void Adafruit_SSD1681::powerUp() {
   }
   EPD_commandList(init_code);
 
+  setRAMWindow(0, 0, (HEIGHT / 8) - 1, WIDTH - 1);
+
+  // Set LUT (if we have one)
+  if (_epd_lut_code) {
+    EPD_commandList(_epd_lut_code);
+  }
+
   // Set display size and driver output control
   buf[0] = (WIDTH - 1);
   buf[1] = (WIDTH - 1) >> 8;
   buf[2] = 0x00;
   EPD_command(SSD1681_DRIVER_CONTROL, buf, 3);
 
-  setRAMWindow(0, 0, (HEIGHT / 8) - 1, WIDTH - 1);
+
 }
 
 /**************************************************************************/

src/drivers/Adafruit_SSD1681.h

@@ -57,6 +57,7 @@ class Adafruit_SSD1681 : public Adafruit_EPD {
   void setRAMAddress(uint16_t x, uint16_t y);
   void setRAMWindow(uint16_t x1, uint16_t y1, uint16_t x2, uint16_t y2);
   void busy_wait();
+  uint8_t _display_update_val = 0xF7;
 };
 
 #endif