Pin constrained processors such as the ESP32 do not have enough pins to drive a 16 bit parallel display, so if you have bought one of those displays it may end up getting unused.
There is however a "trick" with these displays to make them usable as 8 bit parallel displays, providing you are content to use a limited set of colours.
The "trick" is possible because typically all commands only use data bits D0-7 and that is 8 bits, when writing commands the bits D8-15 are "don't care" so could be set to any value. Colours on the other hand do use the full 16 bit width.
This means the display can be driven as 16 bits by a 16 bit library but the data bits D8-17 at the display can wired to D0-7 thus:
Connect D0 to D8 Connect D1 to D9 Connect D2 to D10 Connect D3 to D11 Connect D4 to D12 Connect D5 to D13 Connect D6 to D14 Connect D7 to D15
The control pins DC, CS and WR are wired normally and RD (if available) tied high.
You can now use a limited set of "byte matched" colours to draw graphics on the screen such as these:
// These are byte matched colours #define BM_BLACK 0x0000 #define BM_BLUE 0x1818 #define BM_RED 0xE0E0 #define BM_GREEN 0x0707 #define BM_CYAN 0x7777 #define BM_MAGENTA 0xF8F8 #define BM_YELLOW 0xE7E7 #define BM_WHITE 0xFFFF #define BM_LIGHT_GREY 0xB5B5 #define BM_DARK_GREY 0x6B6B #define BM_PINK 0xF4F4 #define BM_ORANGE 0xE4E4
The library used must support 16 bit displays but you do have to assign the pins for D8-15 in the library to a single unused processor pin or set the pin number to -1 if the library can accept that. That will keep the library thinking it is driving a true 16 bit display.
If you try this then do post back!