[Coco] Re: Converter update

[jdaggett at gate.net]

John

Instead of doing a loop to count between VSYNC IRQs, you can set 
the GIME timer reference to HSYNC and set the timer value to 
slightly less than 262. Which ever interrupts first,  VSYNC or Timer 
can then be used to determine the VSYNC frequency. 

Hardest part is to sync the timer to the VSYNC IRQ service routine.

james

james


On 9 Apr 2005 at 13:49, John Kowalski wrote:

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From:           	sock at axess.com (John Kowalski)
Subject:        	Re: [Coco] Re: Converter update
Date sent:      	Sat,  9 Apr 2005 13:49:11 -0400 (EDT)
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> ><< > Just another note, the ATtiny11
> > 
> > Cool... is 64 bytes of EEPROM enough space for the AL's parameters?
> > That means this could be updated by the CoCo and initialize the AL.
> > >>
> >
> >Maybe.   I haven't written the software yet but we'll see.    This
> >may be a possiblity for any future design.
> 
> Also, since it's programmable, it may also be possible to do something
> like have a push-button on the device - that the MPU will toggle
> different video modes at the push of the button.
> 
> ...Or, no buttons.  Maybe the little MPU could monitor the CoCo's
> VSYNC line - to count how many times a loop executes between VSYNC
> pulses.  This would allow automatically detecting wether the CoCo was
> 50 Hz PAL or 60 Hz NTSC and set the video chip's parameters
> automatically.
> 
>                                    John Kowalski (Sock Master)
>                                    http://www.axess.com/twilight/sock/
> 
> 
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