fix(board): Correct display init for Pimoroni Explorer (RP2350)

Author: tyeth

ports/raspberrypi/boards/pimoroni_explorer2350/board.c

@@ -22,22 +22,50 @@
 
 #define DELAY 0x80
 
-// ST7789V display init sequence for 320x240
+// ST7789V display init sequence for 320x240 parallel bus
+// Based on Pimoroni's pimoroni-pico ST7789 driver configuration
 uint8_t display_init_sequence[] = {
-    // sw reset
+    // Software reset
     0x01, 0 | DELAY, 150,
-    // sleep out
+    // Sleep out
     0x11, 0 | DELAY, 255,
-    // colmod 16-bit color
-    0x3A, 1 | DELAY, 0x55, 10,
-    // inversion on
-    0x21, 0 | DELAY, 10,
-    // normal display mode on
+    // Tearing effect line on (frame sync)
+    0x35, 1, 0x00,
+    // COLMOD: 16-bit color (5-6-5 RGB)
+    0x3A, 1, 0x55,
+    // Porch control (PORCTRL)
+    0xB2, 5, 0x0C, 0x0C, 0x00, 0x33, 0x33,
+    // Gate control (GCTRL) - VGH=13.26V, VGL=-10.43V
+    0xB7, 1, 0x35,
+    // VCOM setting (VCOMS)
+    0xBB, 1, 0x1F,
+    // LCM control (LCMCTRL)
+    0xC0, 1, 0x2C,
+    // VDV and VRH command enable (VDVVRHEN)
+    0xC2, 1, 0x01,
+    // VRH set (VRHS)
+    0xC3, 1, 0x12,
+    // VDV set (VDVS)
+    0xC4, 1, 0x20,
+    // Frame rate control (FRCTRL2)
+    0xC6, 1, 0x0F,
+    // Power control 1 (PWCTRL1)
+    0xD0, 2, 0xA4, 0xA1,
+    // RAM control (RAMCTRL) - for proper endianness
+    0xB0, 2, 0x00, 0xC0,
+    // Positive gamma correction
+    0xE0, 14, 0xD0, 0x08, 0x11, 0x08, 0x0C, 0x15, 0x39, 0x33, 0x50, 0x36, 0x13, 0x14, 0x29, 0x2D,
+    // Negative gamma correction
+    0xE1, 14, 0xD0, 0x08, 0x10, 0x08, 0x06, 0x06, 0x39, 0x44, 0x51, 0x0B, 0x16, 0x14, 0x2F, 0x31,
+    // Inversion on
+    0x21, 0,
+    // Normal display mode on
     0x13, 0 | DELAY, 10,
-    // MADCTL: row/column addressing order and RGB/BGR
-    0x36, 1, 0x00,
-    // display on
-    0x29, 0 | DELAY, 255,
+    // MADCTL: MX=0, MY=1, MV=1, ML=1 (COL_ORDER | SWAP_XY | SCAN_ORDER) = 0x70
+    // This configures the 320x240 display in landscape orientation
+    0x36, 1, 0x70,
+    // Display on
+    0x29, 0 | DELAY, 100,
 };
 
 static void display_init(void) {