I'm working on a project, where I have vertical mirroring in place, and have a working irq split, where the top part is stationary for text, while the bottom part (the irq) contains gfx.
My stationary top portion resides in $2000ppu $2400ppu, while my irq split gfx are located in $2400ppu & $2C00ppu.
I'm having difficulty with my ability to select a nametable from either the stationary part of my screen, or from my irq split.
I tried adding LDA $2002, LDA $#01(load up $2400 nametable) STA $2000, but it doesn't work. I have this within my NMI. And I also tried the same routine within my irq split, but I cant select the nametable either.
Could someone refresh my memory on how to do this correctly. I tried looking up the nesdev wiki on PPU registers, and thought I was doing this right, but I'm not obviously.
what I'm trying to do, is have my irq split scroll from left to right, displaying gfx from one nametable to the other, then I perform vram updates to change the current nametable im having the irq scroll to. I have my irq gfx start in $2400, then I would have gfx written into $2000, so that when the scroll count enter either 00 or FF, and dec's/inc's further, that I have the option to toggle the current viewed nametable, to give the appearance of a smooth transition.
Thanks for reading!
My stationary top portion resides in $2000ppu $2400ppu, while my irq split gfx are located in $2400ppu & $2C00ppu.
I'm having difficulty with my ability to select a nametable from either the stationary part of my screen, or from my irq split.
I tried adding LDA $2002, LDA $#01(load up $2400 nametable) STA $2000, but it doesn't work. I have this within my NMI. And I also tried the same routine within my irq split, but I cant select the nametable either.
Could someone refresh my memory on how to do this correctly. I tried looking up the nesdev wiki on PPU registers, and thought I was doing this right, but I'm not obviously.
what I'm trying to do, is have my irq split scroll from left to right, displaying gfx from one nametable to the other, then I perform vram updates to change the current nametable im having the irq scroll to. I have my irq gfx start in $2400, then I would have gfx written into $2000, so that when the scroll count enter either 00 or FF, and dec's/inc's further, that I have the option to toggle the current viewed nametable, to give the appearance of a smooth transition.
Thanks for reading!