Help with weird behavior on LPCD1758 USB Host implementation

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Hi, i need some helo with a problem that is costing me hours of work.
I am working on a medium sized project with a LPC1758 device. Among
several other things i need to log some data on a USB flash device.

I am trying to use both NXP demo with USBHostLite and the chan's FAT
implementation (http://elm-chan.org/fsw/ff/00index_e.html) and have
the same problem on both (i belive it is on the USB Host stack). Here
comes the problem. When i first programmed the LPC my code was working
all ok, detecting the USB flash device and writing with no problems. I
did test the board several times on different days and worked all ok.
One day it stoped detecting the USB device. It would not detect any
USB flash. I tryed to reprogram it and the problem persisted.

To test that the USB port was working properly i programmed the
example project that comes with Chan's FAT and it worked with no
problem. I recreated a new project and recompiled, and after a few
moves on my code (on places with nothing related to USB) it got back
to work and recognize the USB flashes. After some days again it got
back to do not recognize it. I am geting real crazy here becouse it is
a real weird behavior. When it start not recognizing, i can reprogram
my device and the problem does not go away...

Any sugestion on what can couse that? The problem shows up at any
time, not at some code modification. Something like i am testing today
the board and after a while it happens to do not work anymore. I am
using Code Sourcery as compiler.

Thank you!

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