VDP access from Z80 questions

For anything related to VDP (plane, color, sprite, tiles)

Moderators: BigEvilCorporation, Mask of Destiny

User avatar
Stef
Very interested
Posts: 2948
Joined: Thu Nov 30, 2006 9:46 pm
Location: France - Sevres
Contact:

Re: VDP access from Z80 questions

Post by Stef » Wed Aug 31, 2016 2:53 pm

You have 224 H-Int but in certain condition the V-int is acknowledged as a H-int by the 68000 so you end having a 225th H-int instead of 224 H-Int + 1 V-int but you can't have more than that.

User avatar
Miquel
Very interested
Posts: 437
Joined: Sat Jul 30, 2016 12:33 am

Re: VDP access from Z80 questions

Post by Miquel » Fri Sep 02, 2016 8:27 pm

Ok, just to recapitulate, you don't need hcounter to know in which line you are in a horizontal exception if you vertical exception last less than a vertical blank. So:
- In a standard frame just be sure that the above is accomplished.
- On a loading frame (when you fill most of the VRAM) use hcounter to wait for a vblank to begin, or use fade out to hide artefacts.

Post Reply

Who is online

Users browsing this forum: No registered users and 3 guests