On the m505, the Bus Clock is used to directly drive the external display
controller.  The same reference frequency is used as the pixel clock for the
display, if I recall correctly.

If you increase the Bus Clock frequency, the pixel clock to the LCD is going
to go up too, effectively messing up your vertical frame rate, which will
cause a change in contrast.

The Epson S1D13706 Display Controller (which is used on the m505) has it's
own set of memory-mapped registers (not for the faint-of-heart) that you
could [INSERT MAJOR HACK-ALERT HERE] tweak to change the LCD's display
timing by messing with the H-Total, V-Total, and/or Pixel Clock dividers.

If you did this, you could bring the display's effective frame rate back in
line to correct the contrast, but such changes would be a BIG HONKING HACK,
and would *only* work on the m505.

Doug.

PS: I'm recalling this from memory, so I can't be 100% sure exactly how the
pixel clock is derived, but I'm fairly certain this would be the only way to
bring down the frame rate if you jacked up the system clock.


-----Original Message-----
From: Andrew Perron [mailto:[EMAIL PROTECTED]]
Sent: Wednesday December 5, 2001 17:00
To: Palm Developer Forum
Subject: Palm m505 contrast?


Hi all,

I was recently playing with (software) overclocking an m505 and noticed 
that it was significantly reducing the brightness.

This got me thinking of NoStreak Hack and how it modifies the bus 
bandwidth available to the display.  Would it be possible and feasible 
to increase the contrast of the m505 with similar techniques?

Cheers,

Andrew

P.S. Please at least CC my e-mail as I will not have access to news for 
the next while, thanks.

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