MPC5xxxのトピックRe: MPC5645S with external oscillator

MPC5645S with external oscillator

PCC — Wed, 02 Aug 2017 09:54:12 GMT

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

PetrS — Wed, 02 Aug 2017 10:12:17 GMT

Hi Pierre,

clock should be connected to the EXTAL pin

BR, Petr

PCC — Wed, 02 Aug 2017 11:41:34 GMT

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

robinauriol — Fri, 23 Feb 2018 11:04:01 GMT

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