Re: A86: Many Stupid Questions


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Re: A86: Many Stupid Questions



So if I don't load the new contrast setting to both places, bad things happen... Like what?  I've tried messing around with contrast before by (stupidly) mangling a TI-83 prog and putting it on the 86 to see what would happen... the gremlins in the calculator ate the screen.
 
 
 
 
>3.    Is it possible to adjust the contrast of individual pixels, or do
>you have to adjust the contrast of the whole screen?

Unfortunatly, only the whole screen.  U use Port 2 for that.  A bit of code:

ContDown:
        ld      a,($C008)               ;since port 2 is read only, we must get the
        dec     a                       ;current contrast from a memory address
        ld      ($C008),a               ;decriment it, then load it back to the mem
        out     (2),a                   ;and to the port also
        ret                             ;return to calling code

It is important that u load the new contrast to both places, else bad
things can happen!!

Later,
CHICANE
 

 
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