I'm having a bit of a problem programming the VDP in ASM and hoped someone could give me some pointers to the correct sequence. I'm probably not understanding something correctly.
Taking my cues from the objdump of the rom:
currently I am performing a reset (setting SRS/Clearing SRS)
setting R6 SCREEN_MODE0 =($59), R7 SCREEN_MODE1 =($08), P7 SYSCTRL =($00) for mode P2
setting R8 CTRL =($c2)
setting R13 PALETTE_CTRL =($00)
setting R14 PALETTE_PTR =($00)
I then copy the 16 bytes from the palette table into P1 PALETTE_REG - I use the palette table from the font.h for the rom
i then copy the font data from the font.h to VRAM starting at $00000
i then I set the backdrop colour to $04 as per the ROM code
i then I set 3784 bytes of VRAM starting at $7C000 to $00
All I get is a white screen, just like its not been programmed. attempting to write anything to the VRAM pattern table doesn't change anything (i am writing 2 bytes per location).
I get a clear 2 weeks to work on something and I've spent 3 days banging my head against something so basic
![Embarrassed :oops:](./images/smilies/icon_redface.gif)
Thanks
Chris