Glamo problem on GTA02
andy at openmoko.com
Thu Jul 31 14:53:15 CEST 2008
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Somebody in the thread at some point said:
|> What is on the LCM at that time, is it all white by any chance?
| I have seen it all white, and I have seen it all black. Back when it
| used to boot once in 50 times, I often saw the LCM seeming to "decay"
| from a previously shown picture before bringing up the u-boot menu. But
| today it was mostly black while doing this, and then at the end of the
| day it did it while showing completely white for a short while.
| Is there any test points I can probe to prove your theory? Anything I
| can put a probe on to affect the capacitance and make it work (since you
| said in the other thread that your CRO probe was able to affect it)?
Not testpoint but if you popped the main can (your device is going to
end up like my ones, a "skelephone" at this rate :-) ) you can fairly
easily test for this insane Glamo Reset / scope probe detector stuff.
The two ends of the resistors show in the pic are both RST#.
LCM all-white is direct result of reset action. However, it can get
itself into various half-configured states, that and the crashes on
framebuffer access will be the black LCM outcomes.
One other thing is important if you are interested to poke at this,
there is a testpoint for nWAIT to CPU (controlled by Glamo) just under
the backup battery. Of the two testpoints there, it is the one nearest
the centre of the PCB. If you see that guy stuck low, it is because
Glamo has froze the external memory bus for you, he's normally high
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