Add P8B mirrored version definition.

Author: izzeho

src/CMakeLists.txt

@@ -804,6 +804,7 @@ elseif(TARGET_DEVICE STREQUAL "MOY-UNK") # P8b mirrored
   add_definitions(-DCLOCK_CONFIG_LF_SRC=0) # RC
   add_definitions(-DMYNEWT_VAL_BLE_LL_SCA=500)
   add_definitions(-DCLOCK_CONFIG_LF_CAL_ENABLED=1)
+  add_definitions(-DDISPLAY_DRIVER_MIRROR)
 else()
   message(FATAL_ERROR "Invalid TARGET_DEVICE")
 endif()

src/drivers/St7789.cpp

@@ -21,7 +21,10 @@ void St7789::Init() {
   MemoryDataAccessControl();
   ColumnAddressSet();
   RowAddressSet();
+// P8B Mirrored version does not need display inversion.
+#ifndef DISPLAY_DRIVER_MIRROR
   DisplayInversionOn();
+#endif
   NormalModeOn();
   SetVdv();
   DisplayOn();
@@ -62,7 +65,12 @@ void St7789::ColMod() {
 
 void St7789::MemoryDataAccessControl() {
   WriteCommand(static_cast<uint8_t>(Commands::MemoryDataAccessControl));
+// P8B Mirrored version sets MX bit high in MADCTL register to flip about vertical axis.
+#ifdef DISPLAY_DRIVER_MIRROR
+  WriteData(0x40); // MY(0) MX(1) MV(0) ML(0) RGB(0) 0 0 0
+#else
   WriteData(0x00);
+#endif
 }
 
 void St7789::ColumnAddressSet() {