RE: Unknown holes in the motherboard of the CBM610

Hallo Mia,


> The 18MHz clock is needed for the pixel clock anyways

I completely forgot that. But OTOH, there are a lot of systems that use two different clocks; one for the video and one for the system. 


> but I see no reason for throwing away that possibility to control timing exactly.

We'll see what can be done. But I know one possible reason to keep it:  what did come to my mind is the so called "snow effect" on video cards when writing directly to the video memory. A good example is the CGA card. But for one or another reason the MDA card doesn't suffer this problem. One possibility to solve the problem is to halt the CPU the moment it wants to write to the memory when it is read by the video system at the same time. But I'm quite sure the MDA card doesn't do this. If anyone knows how snow can be avoided in other ways and want to share this knowledge, please be welcome!


Met vriendelijke groet / With kind regards, Ruud Baltissen

www.Baltissen.org





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