S12 / MagniV MicrocontrollersのトピックPLL not locking on NE64

PLL not locking on NE64

WayneHowell — Wed, 20 Jun 2007 23:16:09 GMT

Hi,

I'm using the MC9S12NE64. Initially been using the Axiom development board.

I've developed our own hardware. I cannot get the PLL to lock.

I've used exactly the same crystal circuit as the Axiom board.

Any ideas would be appreciated.

Cheers

Wayne

Re: PLL not locking on NE64

Lundin — Thu, 21 Jun 2007 16:15:38 GMT

I assume that you are also using the same PLL filter as they did between the XFC and VDD PLL pins? And a decoupling capacitor from VDD PLL to VSS PLL? Are your certain you are using the right values?

Is the oscillator circuit working properly? Have you measured the actual frequency? If there is anything wrong with it, the HCS12 will still work in "limp-home" mode around 2MHz, since the self-clock feature is enabled by default out of reset. All timing and baudrates will naturally be messed up, though.

Re: PLL not locking on NE64

WayneHowell — Thu, 21 Jun 2007 16:28:19 GMT

Many thanks - it had indeed gone into 'limp home' mode.

Bad connection on the xtal pin.

Running happily now.

Thanks

Wayne