Jump to content

Trying out a Scroll Routine

Recommended Posts

This is done in 100% Assembly Language.


I am only scrolling 640 characters starting from Column 0, Row 0 or $1800 using Mode 2


I write my 640 bytes sending the data through port $BE with my pointer pointing to the pattern table.


All works great.


I set up a routine the polls the controller, up and down.


I send the offset to +32 or minus 32 within my pattern.


The bottom line this does make the pattern scroll up and down very effectively.


So much effectively that it is too fast.

Also, because it movies on one 8 bit pattern line at a time.  Every 32 patterns.  It tears.


Are there any timing routines in BIOS or the community to slow this down.

Maybe ideas on double buffering?


I sent a PM to PkK on how he was able to use the entire 1k of Coleco Ram so maybe I can use that for a screen double buffer but he has yet to return my calls.
Even then I would have to figure out how to double buffer with a Colecovision.

I could share some code but it is essentially how I described it.

I am basic in experience.
All I know so far is what I seen in Tony Cruise's video series.
I was following up till his last video which seems to be a long time ago.



Basically, what I am attempting to do is have a pattern of my choice, size and shape be able to move up and down the screen and look smooth with the limited resources a Colecovision has.  Nothing fancy, no round corners or special colors.  All filled in 8x8 blocks.

Edited by CaptainCozmos20863
Link to comment
Share on other sites

  • 2 weeks later...

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.


  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Create New...