Hi.

1. openmsx -ext gfx9000 romname.rom

2. You have all that information in the teambomba's g9klib, and searching v9990 in the internet: v9990 e-vdp-iii.
      Normally you will use ports 0x60-0x67

3. At first I recommend using openMSX-debugger for testing. You can write directly on the registers and go see how it behaves, and then fret the VRAM. When you are clear about how it works, start typing code.


vpoke:
;writes B value at DHL address
     di
     xor a
     out[0x64],a   ;register 0 selected

     ld a,l
     out [0x63],a  ;this will write L value to register 0. (Low byte)
     ld a,h
     out [0x63],a  ;this will write H value to register 1. (Med byte)
     ld a,d
     out [0x63],a  ;this will write D value to register 2. (High Byte)

     ;VRAM pointer points to DHL
     ld a,b
     out [0x60],a 
     ei
     ret
     

i'm trying this now:


nothing happens, just a blank display when i enter "set videosource gfx9000" on the OpenMSX console

btw, how can i replace "set videosource gfx9000" with a command line, so i don’t need to go to the console for entering that console command?

it’s working! thanks!
and thanks a lot for the OpenMSX command for display switching, i didn’t know that!

and about the "not necessary", they actually were in my case, i was trying to create libraries for ZX-Basic:

example08.bas

library/msxgfx9kvdp.bas:

library/msxgfx9kpalette.bas:

library/msxgfx9kvpoke.bas:

nevermind, i found that, it is "out $67,1"

You should use the autoinc register feature, maybe creating another function: