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MPC5645S ko with external oscillator

Question asked by Pierre CAZENAVE on Aug 3, 2017



The cpu runs correctly with 16MHz internal RC   , and runs correctly with an 8Mhz QUARTZ,

But when connecting an  External oscillator 8MHZ MASTERCRISTAL MCS01Y-B-8MHZ  level  1,2V , square wave 

=> 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 EXTAL is short (3.5mm) , the XTAL is left unconnected (we try too with EXTAL grounded )


With 3 différents boards , the problem is the same 


Seems to be a soft initialization problem


Can any body help us ?

Thanks for all