Re: writing to cart port (not IO space) on 64

From: Daniel Kahlin <ml-tlr_at_kahlin.net>
Date: Sat, 25 Feb 2017 19:08:32 +0100 (CET)
Message-ID: <Pine.LNX.4.62.1702251905410.30008@yxa.extundo.com>
On Fri, 24 Feb 2017, Jim Brain wrote:

>> ; optional to avoid visible glitches, wait until border area
>>         ldx     #$30
>> lp:
>>         cpx     $d012
>>         bcc     lp
> OK, I partially understand this.  Is it because color ROM is no longer wired 
> to anything?  Because, I assume you could relo the screen RAM to somewhere in 
> the first 4kB

It's because the character ROM is not visible to the VIC-II in ultimax 
mode.

I suppose you could put the charset in RAM and have full speed writing 
with the screen visible.

/Daniel


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Received on 2017-02-25 19:00:02

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