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Switching Vybrid Core Power Source

Question asked by Benno Jung on Aug 19, 2014
Latest reply on Sep 8, 2014 by Naoum Gitnik

Hello

 

We have some identical boards with the Vybrid Processor on it.

One of them doesnt work from the beginnings, one stopped work after some days of software testing.

 

The problem is the initializing/start up of the board. When the board is powered up, the line EXTAL goes to 0.6V for about 2ms. Then its tied low again. This is identical on the good and the bad boards.

But then: the good boards set the EXTAL after a while again to 0.6V and the crystal starts working. On the bad boards EXTAL stays low, and the initialisazation stops on the Point /* Wait for PLL lock. */.

 

What can be the Problem? The boards are (should be) identical, the software is the same...?

Pic1 below: power up, all boards start up like this.

Pic2 below: good boards set EXTAL to 0.6V like on the pic, on bad boards EXTAL stays low forever...

 

Thanks in advance.

 

 

crystal-error1.png

crystal-noerror.png

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