Re: Another idea for outputting to VGA/DVI/HDMI

[Sheldon Simms <wssimms@gmail.com>]

On 2013-03-23 20:53:33 +0000, Charlie said:
> The problem with any card that uses data from the slot bus is the 
> inability to synchronize with the Apple video output.  This is the way 
> the Carte Blanche works and I'm pretty sure the Second-Sight card 
> worked in a similar way (although I've never seen one).  The Carte 
> Blanche output visually is quite good although it doesn't have the NTSC 
> look. This works well with most video but because of the lack of 
> synchronization, programs that rely on timing with Vertical Blanking or 
> interrupting to change palettes, modes, etc. don't do well.
>
> By the way sampling the bus doesn't have to be that fast.  The Carte 
> Blanche does it a 50MHz.

50 Mhz is plenty fast enough, I was just wondering whether the 
Beaglebone can do it that fast.

Video sync is a solvable problem. Either take the signal where it is 
available (IIe slot 7, etc.) or write a program that will allow the VGA 
card/software to sync.