[Color Computer] Re: [Coco] New CoCo game demo: Glove.

[James Diffendaffer]

>> I don't know of any way to detect which output is being used other
>> than to ask the user....
>
>    I remember reading some speculation somewhere that one of the unused
>pins in the RGB header might originally have been intended to be used to
>detect the RGB monitor, perhaps through an unused PIA line.  [Digging
>through CoCo 3 service manual...]  Aha.  According to the schematic, pin
>10 of the RGB port on the bottom of the CoCo 3 does connect to pin 13
>(Port B, bit 3) of  IC4, and it's pulled high with some resistors.  
>And
>the service manual also says on page 10 that bit 3 of $FF22 is "RGB
>Monitor Sensing INPUT".  However, the RGB monitor may not actually drive
>the line low.  In the manual for the CM-8 it calls pin 10 a No Connect. 
>I suppose a ?(PEEK(&HFF22)AND 8) with an RGB monitor plugged in should
>yield an answer.  Or something like that.
>    What one could do if the monitor sense input is not used by the CM-8
>is make a little cable adaptor that would ground pin 10 when the RGB
>monitor was plugged in.  You could test the PIA input and conclude that
>a (modified) RGB monitor is plugged in if it is low.  If it is high, it
>is either a composite monitor or an unmodified RGB.  In that case, ask
>the user.
>
>JCE

I'm aware of the pin but at this point in time you'll probably detect
a handfull of machines at best.  On the other hand, once people know
something is actually testing it that may change.  LOL
I think any new CoCo clone should take advantage of this so that new
software doesn't have to ask.
Do any of the old games actually use this or do they all ask what
video output you are using?





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