[Coco] Re: [Color Computer] Re: Adapter from Coo3 to SVGA

[RJRTTY at aol.com]

In a message dated 4/5/05 8:02:29 AM Eastern Daylight Time, 
Torsten at Dittel.info writes:

<< That's odd. And I don't know enough about hardware to say that a cheap 
 PAL or GAL with kind of a shift register containing the code sequence to 
   programm the devices would serve. >>

As a matter of fact the Matco composite to SVGA converter uses
a Pal chip to set up its AL250 whenever power is
applied to it.   It's mostly to configure the text messages that
appear on the screen to label different modes of operation.
     I am ashamed to say I dont know enough about Pal and Gal
chips to consider them as an alternative to programming
the video chips with the coco3.   Maybe somebody here could
briefly explain or point me to information on line I could
consume?    I would hate to overlook an elegant solution
because of my ignorance.
        Interestingly enough,  I modified a Matco converter to accept
the RGB from the coco3.   I cut the data lines going to the
AL250 from the SAA7111A  Philips video decoder then
I used about 4 Quad comparators as a fast low res
ADC to convert the analog RGB of the coco3 to RGB565.
I did this in order to evaluate how effective the AL250
conversion was before I continued with the project.  The
display was off center to the right even after it was
programmed by the on board pal chip so the default
configuration of the video chips may have been set
to accomodate other devices such as video decoders.
Our use of these chips to process RGB to RGB is
likely out of the norm from what the designers
intended for those chips.

       DERN COCO USERS.....PERVERTING
OUR TECHNOLOGY LIKE THAT !!!!    :))))))

I really need to get around to fixing my Matco
converter someday but I'm a little occupied right
now.   :))

Roy