[Coco] Raster position

[Sandro Mestre]

Hello, I'm new to this list.

I would like to code a game for the Coco1/2. I usually code for the
commodore c64 so I am aquainted with the 6502 but I also can code for the
motorolas 6800, 6809 and 680000. During the last days I have coded a sprite
engine for a computer with a 6809E and it is working great and then I
thought that I could code also the game for the Coco/Dragon computers.

I need to know if there is a register that I can poll to check the current
raster position or if there is another way to know when the VDP starts
painting the horizontal borders. I am asking this because as many will know
if I paint the sprites there(borders) there will be no flickering. Another
option I have would be to use double buffering but then this would eat much
more memory and that would be perhaps a no go.

How safe is it to use the high speed poke on a game? Do coco games use it?

Thanks

Wood