SNES programming tutorial. Example 11.
https://github.com/nesdoug/SNES_11
This page is under construction.
HDMA is a way to write to PPU registers while the screen is drawing. You can change values at specific scanlines, to create unique effects.
The H is for H-Blank. Remember before, when we talked about V-blank (vertical blank), where the PPU isn’t doing anything for a short while after drawing each screen? Well, it also pauses a VERY SHORT time after drawing each horizontal line. Just long enough for the 8 HDMA channels to quickly change a register or send data, before the screen goes to write the next line.
They work in order, 1,2,3,4,5,6,7,8. They can all write 1 thing (1,2 or 4 bytes) on the same line.
HDMA uses the same registers as the DMA registers, and you shouldn’t use both at the same time.
(link)
This page is under construction.