[Coco] Access to 225 lines in BASIC

Nick Marentes nickma2 at optusnet.com.au
Mon Oct 20 14:08:50 EDT 2014


On 21/10/2014 3:54 AM, Robert Gault wrote:
>
> So far so good, but you wanted 225 lines. That gets very tricky as it 
> requires 160x225=$8CA0 bytes but Task1 (used for hi-res graphics) 
> currently has $8000 bytes available.
>
> I have been able to make Basic use 225 lines in HSCREEN2 mode but it 
> requires tricking Basic into using an additional MMU block in Task1. 
> If you try all the needed POKEs at once, Basic crashes. You have to 
> gradually increase the amount of memory used by HCLS at $E6E6 until 
> the full $8CA0 amount has been accessed.
>
> As yet I've not been able to force the 320x225x16 mode in a single 
> pass of a Basic program.
>
> If you want a demo program, let me know.
>
> Robert
>
>

I've managed to alter my screen layout to accomodate the 200 lines. 208 
was the target but this was difficult for the reason you explained.

Thanks


More information about the Coco mailing list