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MPC5645S with external oscillator

Question asked by Pierre CAZENAVE on Aug 2, 2017
Latest reply on Feb 23, 2018 by Robin AURIOL

Hello,

 

The cpu runs correctly with 16MHz internal RC , we want to use the internal  PLL with connecting an  External oscillator 8MHZ

=> the cpu doesnt start correctly because it detects 

S_FXOSC =0 (0 fast external crystal oscillator (4-16 MHz) is not stable)

 

the oscillator is  MASTERCRISTAL MCS01Y-B-8MHZ  level is 1,2V , square wave is clean , stable and accurate 8MHZ

The trace of XTAL is short (3.5mm) , the EXTAL is left unconnected (we try too with EXTAL grounded )

 

With 2 différents boards , the problem is the same 

 

Can any body help us ?

Thanks for all

 

Pierre CAZENAVE

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