Re: Blurry picture

From: Segher Boessenkool <segher_at_kernel.crashing.org>
Date: Thu, 17 Nov 2011 22:09:11 +0100
Message-Id: <F5EB0C9D-3182-48CE-A3FF-E18AED00EFB4@kernel.crashing.org>
> The vertical stripes really depend on the chip run and are, from  
> what I have seen, more pronounced on the C128. I don't really  
> notice them on the C64 with 8565R2 I use most of the time.

So what causes the stripes?  They coincide with AEC/Phi2, but that  
doesn't
mean it causes it.  I don't see anything on the chip that could cause  
it,
so maybe it is interference on the board?

> What I do notice are the grey dots of the HMOS-II VICs.

That seems to be caused by the different boards, not the different VIC
revision: the #CS signal is too early (relative to the data bus), which
means that when you write a colour reg, it first gets written with all
ones, getting the correct colour only later that same cycle.  Delaying
the #CS signal (adding a cap is enough) gets rid of the dots.


Segher


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Received on 2011-11-17 22:00:04

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