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Coldfire MCF52254 having problems booting

Question asked by Angelo Quattrociocchi on Jun 29, 2013
Latest reply on Aug 25, 2015 by Angelo Quattrociocchi

I have some custom boards using the MCF52254 which normally power up fine, but a recent batch is having a problem booting up frequently.  I see that when it is not running that the crystal is dead.  If I cycle the power quickly the crystal starts fine and the application boots normally.  If I let it stay off for too long (more than ~10s) the clock doesn't start and it doesn't boot.  The attached image shows the crystal circuit, which is based on the MCF52259 tower reference design.

 

I don't know of any changes between the last batch and this one, but they do apply a humiseal coating and I suspect it might be affecting the tuning.  I've tried to remove the coating and I don't think it had much effect, but I'm not sure I got enough off.

 

Any thoughts on what I could try?

 

Thanks

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