The Gameboy Uses an LCD display with a resolution of
160x144. The supported sprites are 8x8 and 8x16. There
is no way to use 32x32 sprites, so don't ask. The
gameboy supports a max of 40 sprites with 10 on one
horizontal axis at one time.
Before writing any data to the videomem you have to disable
the LCD-Display (display_off();).
On a real gameboy you are not able to upload data to the
videomem while the LCD is processing.
Gameboy emulators may not suffer from this problem.
If your programm needs to write to the videomem while displaying
something you have to be in the Vertical-Blank.It´s also possible
to write data to the videomem while being in the Horizontal-Blank
but this needs a special interrupt handling.
Also have in mind that most emulaotrs will fill all
RAM/ROM with zeros. A real gameboy won´t do that. At the end of
all programs, it is a good habit to fill at least the visible
screen data to all 0s.
All of the information provided is compiled from various
sources and own experiences. This document is for educational
purposes and ´homebrew´ GB-development.
GameBoy and CGB is copyrighted by Nintendo Co., LTD.