After fidling around I finally got the hang of all this assembly stuff but the VDP still remains a mystery to me. I have read the V9938 manual 10 times over and my brains hurt by now.
So I send some bits and bytes to the VDP port and I eventually manage to change the screen mode and even change it back after hitting the esc key but I really just cannot understand how to put something into that screen.
I have tried putting some bytes into the vram in the hope to see something happen on screen5 but all I get is a line of white dots on a blue screen. No colors, just anoying white dots. These dots are my written bits though but the adressing into the vram memory also doesn't turn out as I expect.
Basicly: How can I for example, by just writing bits and bytes into the vram position a block/line whatever on the screen in the color I want?
Does the VDP read the contents of the VRAM automaticly and displays this onto the screen?


Yes your info has got me started.