Bypassing the Pokemon Mini drawing circuit
I changed one of my tutorials so that it displays an image without actually using the PMs drawing circuit. The PM offers two hardware registers – 0xFF and 0xFE – to access the LCD controller directly, this gives us the opportunity to send whatever we want to the display controller.
I figured out some commands of the controller using this datasheet which i found on darkfaders website, but not all commands in the datasheet seem to work or the PM hardware interferes when you try to use them.
The PM drawing circuit does exactly the same as my code, but it doesn’t draw directly to GDDRAM, instead it first draws to the frame buffer at 0×1000 and while the LCD is in VBLANK it copies the framebuffer over to the LCD controller GDDRAM. Of course writing the GDDRAM yourself saves some RAM since you don’t have to use the framebuffer but it is slow and you have to draw everything yourself.
Download the source+binary here – this will, of course, only work on real hardware.