P96 on CV64

[patrik]

@AMIGAZ:

You can get some wierd effects if you max out the CV64:s pixelclock, especially in 24-bit screenmodes. For 24-bit screenmodes the maximum pixelclock is 50MHz which corresponds to a 800x600@75Hz vesa screenmode if I am not mistaken. The card/chip is speced to handle this, but I get some really wierd effects when moving windows etc. Just lowering the pixelclock a bit sorts the problem - when using a 800x600@72Hz vesa screenmode the problems are gone.

Generally the Trio64 chip and I assume the Virge chip too as it is based on the previous - is quite good at giving a slightly erronous picture when you start to reach its maximum pixelclock. In 8-bit screenmodes around 130MHz pixelclock, you get the problem that it seems to "forget" to draw some pixels, making for example straight vertical lines look jagged.


/Patrik

[patrik]

@AMIGAZ:

No problem :=).

Yeah, definately. The Trio64 chip is only speced for 50MHz at 24-bit and you often need to go down to ~48MHz to make it behave correctly.

You could always use a 800x600 16-bit screenmode instead to achieve the refresh-rates you want. Admittedly if your backdrop contains large gradients areas of rather pure red, blue or green you might have to give your backdrop a touch with an image-processing software, but the responsiveness you gain is definately worth it.


/Patrik