MPC5645S with external oscillator

[PCC]

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

[robinauriol]

Hi,

I have the same problem, do you find the solution to this problem Pierre ?

The crystal configuration works fine, but it doesn't work with only an oscillator on the EXTAL pin and nothing on the XTAL pin.

I have maid the same circuit on a MPC5646C and it works !

Is the MPC5645S more sensitive ?

Thanks

Robin

[PCC]

Hi Petr,

I apologize , i wrote an error  in my post , i was talking about EXTAL as an entry for the oscillator ,and XTAL is not connected.

The oscillator is really connected on the EXTAL entry  an XTAL is left non connected.

But it doesn'twork...

Thanks for your help 

Pierre

[PetrS]

Hi Pierre,

clock should be connected to the EXTAL pin

BR, Petr