Date   : Fri, 10 Dec 2004 12:41:15 +0000
From   : Richard Gellman <splodge@...>
Subject: Re: Video ULA shenanigans

Tom Walker wrote:

>>Firstly, such a thing is impossible, not because of
>>    
>>
>rates, etc.,
>  
>
>>but because of the way the chip is designed. The
>>    
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>chip
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>>generates a 40x25 display. No arguments. 
>>    
>>
>
>Doesn't the Firetrack loader generate a teletext
>display with more than 40 columns though?
>
>Tom
>  
>
Not quite.

When we say "40-character" we're referring to the number of characters 
per line the TT chip generates. Firetrack does something weird with the 
CRTC chip. Its still 40 characters wide, but the sync pulses are in 
weird places causing the display to wrap. Quite why the TT is happy with 
this I do not know, I would expect it to screw up completely.

Firetrack then uses custom routines to work out where to display things. 
And IIRC, it was less than 40 characters.

-- Richard Gellman