[Coco] replacing main rom
jdaggett at gate.net
jdaggett at gate.net
Thu May 12 16:54:08 EDT 2005
William
Thanks for the input and yes I am familiar with that part of the code.
When this came up about a rom change and the GIME interrupts it
spurred one of my lingering problems with the GIME FPAG project
that I am working on. The timer. No where in the basic code is it
used and even with the hardware character blick I anm not so
certain that it is used for that. It maybe however that the blink timer
and 12 bit timer at $FF94/$FF95 share the same frequency source
and prescalar.
Oh well even with the enhancements, I am postive that there is still
some backward compatibility.
james
On 11 May 2005 at 21:06, William Astle wrote:
Date sent: Wed, 11 May 2005 21:06:44 -0600
From: William Astle <lost at l-w.ca>
To: CoCoList for Color Computer Enthusiasts
<coco at maltedmedia.com>
Subject: Re: [Coco] replacing main rom
Send reply to: CoCoList for Color Computer Enthusiasts
<coco at maltedmedia.com>
<mailto:coco-
request at maltedmedia.com?subject=unsubscribe>
<mailto:coco-
request at maltedmedia.com?subject=subscribe>
> Someone else already pointed out that you can demonstrate that the
> character blink rate is determined by the timer. The timer itself has
> two possible input frequencies which correspond to the vertical and
> horizontal syncs (IIRC).
>
> The cursor blink is done in the "console in" routine which is
> "patched" by Super Extended basic to handle blinking the cursor on the
> hires text screen. It doesn't do anything so clever as count
> interrupts or anything like that to blink the cursor. IIRC it's merely
> Y times through the "wait for a keypress" loop then flip the cursor.
> Lather, rinse, repeat. Just like on the 32 column screen, just with
> only 2 states. You can demonstrate that it doesn't count interrupts or
> anything so clever by switching to high speed mode and you'll see the
> cursor blink rate doubles.
More information about the Coco
mailing list