8-bit Microcontrollers中的主题 Re: Resonator GZ08 GR16A etc.

Resonator GZ08 GR16A etc.

galahad — Thu, 10 Jan 2008 15:27:56 GMT

A happy new year to everyone...

Is it possible to use a 4MHz or 8MHz Murata resonator instead of a crystal on a MC908GZ08 or GR16A? (3.3V) I couldn't find any useful informations so far.

Thank you from germany.

Re: Resonator GZ08 GR16A etc.

bigmac — Thu, 10 Jan 2008 21:58:33 GMT

Hello,

It should be possible for a ceramic resonator to be used in lieu of a crystal. Of course, the accuracy and stability of the resonator will be much degraded, compared with a crystal.

A two-terminal resonator device would simply replace the crystal in a Pierce oscillator configuration, and would also require a pair of suitable value external capacitors, similarly to the crystal. A three-terminal style resonator integrates the capacitors internally within its package.

Regards,

Mac

Re: Resonator GZ08 GR16A etc.

galahad — Fri, 11 Jan 2008 19:51:23 GMT

Thank you, Mac

Is it common to use resonators in high volume production although it is not specified by freescale? Or is it risky? Any experiences? We've done it with a 68HC11, and i know other companies did it too, but...

Re: Resonator GZ08 GR16A etc.

bigmac — Sat, 12 Jan 2008 10:26:39 GMT

Hello,

I presume the reason a ceramic resonator might be chosen over a crystal would be one of cost. I am not aware that the resonator would be substantially less reliable.

I have previously used resonators in old HC705 projects. However, for newer HC908 and HCS08 projects I have generally found the use of the internal oscillator to be adequate for many applications. For those cases where this is not sufficiently accurate and stable, I would then use a crystal.

My production batch quantities are not sufficiently large for small cost differences to be significant, and I generally have more flexibility in the choice of crystal frequency, for example. 4.9152 MHz.

Regards,

Mac