split the two invert functions

main/hello_world_main.c

@@ -46,7 +46,7 @@ void app_main()
         LCD_setStr(buf, 4, LCD_HEIGHT - 10, 0);
         LCD_updateDisplay();
 
-        vTaskDelay(1000 / portTICK_PERIOD_MS);
+        vTaskDelay(900 / portTICK_PERIOD_MS);
     }
     printf("Restarting now.\n");
     fflush(stdout);

main/nokia.c

@@ -312,7 +312,6 @@ static void LCD_SendByte(bool data_or_command, uint8_t data)
     assert(ret == ESP_OK);            //Should have had no issues.
 }
 
-
 // This function sets a pixel on displayMap to your preferred
 // color. 1=Black, 0= white.
 void LCD_setPixel(int x, int y, bool bw)
@@ -529,8 +528,11 @@ void LCD_clearDisplay(bool bw)
 // specific x,y coordinate.
 static void gotoXY(int x, int y)
 {
-    LCD_SendByte(LCD_COMMAND, 0x80 | x);  // Column.
-    LCD_SendByte(LCD_COMMAND, 0x40 | y);  // Row.  ?
+    const uint8_t cmd[2] = {
+        0x80 | x,
+        0x40 | y,
+    };
+    LCD_SendBytes(LCD_COMMAND, cmd, 2);
 }
 
 // This will actually draw on the display, whatever is currently
@@ -548,28 +550,26 @@ void LCD_updateDisplay()
 void LCD_setContrast(uint8_t contrast)
 {
     spi_device_acquire_bus(hSPI, portMAX_DELAY);
-    LCD_SendByte(LCD_COMMAND, 0x21); //Tell LCD that extended commands follow
-    LCD_SendByte(LCD_COMMAND, 0x80 | contrast); //Set LCD Vop (Contrast): Try 0xB1(good @ 3.3V) or 0xBF if your display is too dark
-    LCD_SendByte(LCD_COMMAND, 0x20); //Set display mode
+    const uint8_t cmd[3] = {
+        0x21,  //Tell LCD that extended commands follow
+        0x80 | contrast,//Set LCD Vop (Contrast): Try 0xB1(good @ 3.3V) or 0xBF if your display is too dark
+        0x20,//Set display mode
+    };
+    LCD_SendBytes(LCD_COMMAND, cmd, 3);
     spi_device_release_bus(hSPI);
 }
 
-/* There are two ways to do this. Either through direct commands
-to the display, or by swapping each bit in the displayMap array.
-We'll leave both methods here, comment one or the other out if
-you please. */
-void LCD_invertDisplay()
+void LCD_invertDisplay(bool invert)
 {
-    /* Direct LCD Command option
-    LCDWrite(LCD_COMMAND, 0x20); //Tell LCD that extended commands follow
-    LCDWrite(LCD_COMMAND, 0x08 | 0x05); //Set LCD Vop (Contrast): Try 0xB1(good @ 3.3V) or 0xBF if your display is too dark
-    LCDWrite(LCD_COMMAND, 0x20); //Set display mode  */
+    LCD_SendByte(LCD_COMMAND, 0x0C | invert);
+}
 
+void LCD_invertDisplayData()
+{
     /* Indirect, swap bits in displayMap option: */
     for (int i = 0; i < (LCD_WIDTH * LCD_HEIGHT / 8); i++) {
-        displayMap[i] = ~displayMap[i] & 0xFF;
+        displayMap[i] ^= 0xFF;
     }
-    LCD_updateDisplay();
 }
 
 //This function is called (in irq context!) just before a transmission starts. It will
@@ -599,7 +599,7 @@ void LCD_setup(void)
         .max_transfer_sz=LCD_WIDTH * LCD_HEIGHT, // ??? this doesnt seem to do anything in the driver
     };
     spi_device_interface_config_t devcfg = {
-        .clock_speed_hz=2 * 1000 * 1000, // Hz
+        .clock_speed_hz=4 * 1000 * 1000, // Hz
         // enable signal lead/lag
         .cs_ena_pretrans = 0,
         .cs_ena_posttrans = 0,
@@ -624,7 +624,7 @@ void LCD_setup(void)
 
     const uint8_t magic[6] = {
         0x21, // Tell LCD extended commands follow
-        0xB0, // Set LCD Vop (Contrast)
+        0x80 + 40, // Set LCD Vop (Contrast)
         0x04, // Set Temp coefficent
         0x14, // LCD bias mode 1:48 (try 0x13)
         //We must send 0x20 before modifying the display control mode

main/nokia.h

@@ -59,11 +59,11 @@ void LCD_updateDisplay();
 // 40-60 is usually a pretty good range.
 void LCD_setContrast(uint8_t contrast);
 
-/* There are two ways to do this. Either through direct commands
-to the display, or by swapping each bit in the displayMap array.
-We'll leave both methods here, comment one or the other out if
-you please. */
-void LCD_invertDisplay();
+/* Invert colors */
+void LCD_invertDisplay(bool in_data);
+
+/* Invert colors (hard change in data; does NOT send to display immediately) */
+void LCD_invertDisplayData();
 
 //This sends the magical commands to the PCD8544
 void LCD_setup(void);