[PATCH] fix-glamofb-flicker-72hz-refresh.patch

[joerg]

Am Mo  10. März 2008 schrieb Andy Green:
> - gpg control packet
> Somebody in the thread at some point said:
[...]
> > Also, you said the PCLK signal is very corrupted due to the R-C. Even 
while
> > apparently not causing actual trouble, this should be given a closer look, 
to
> > feel good regarding worst case scenarios. Someone has to have an 
explanation
> > _why_ this C is there and should be this value. Otherwise just replace 
with a
> > better value for MP?
> 
> I guess the idea is emissions LPF... I attach what it does to this
> 24.5Mhz clock.  This is on a 200MHz bandwidth 'scope, that's really what
> the "square wave" actually looks like at the LCM connector :-)
> 
> If there is no objection maybe we could try 12pF or somesuch there
> instead of 47pF.  But at this time near production I can imagine the
> urge is to let all sleeping dogs lie.
> 
> -Andy
> 

From LCM-datasheet:
abs. max. ratings: (for PCLK, @VDDIO=3,0V)
VInput-Low: <= VDDIO * 0,3 = 0,9V
VInput-High:>= VDDIO * 0,7 = 2,1V

I think this scope-plot signals really critical situation for PCLK.
NB: with higher clock freq , situation gets worse!

cheers
jOERG