topic Re: Clock generation without external parts in 8-bit Microcontrollers

Clock generation without external parts

WimmerChris — Wed, 09 May 2007 12:05:19 GMT

Hello everybody,

i've a short question: Which HC08 MCUs like the QT4 or QB8 have an internal oszilatior, so that i can run them with out external parts?

Thanks for help!

With best regards

Christian Wimmer

Re: Clock generation without external parts

peg — Wed, 09 May 2007 12:41:20 GMT

Hi Chris,

This document helps:

http://www.freescale.com/files/microcontrollers/doc/fact_sheet/8BITCIPRODMPFS.pdf

The clock type column gives the acronym for the clock module type, from there and from a few checks you should be able to work it out. They don't make it real easy, do they?

Re: Clock generation without external parts

WimmerChris — Wed, 09 May 2007 23:46:19 GMT

Hi Peg,

thanks for the overview it's pretty good. But i'm sorry it doesn't help me in my problem because, if you look at the QT4A or the QB4 for example you will see that there is a "OSC" at the clock type. (Both devices have an internal oscillator.) But the JL8 (there is also a "OSC" ) didn't have an internal oscillator.

Thanks for your help.

Best regards.

Christian

Message Edited by WimmerChris on 2007-05-09 06:48 PM

Re: Clock generation without external parts

bigmac — Thu, 10 May 2007 01:26:55 GMT

Hello Chris,

The HC908 devices that have a trimmable internal oscillator are limited to a few series only - Qx series, EY, GT, but not many others come to mind. A few other series do have an internal oscillator, but is not accurate or stable with voltage and temperature.

Trimmable internal oscillators seem much more prevalent within the various 9S08 series, which are more recent devices.

Regards,

Mac

Re: Clock generation without external parts

peg — Thu, 10 May 2007 06:03:53 GMT

Hi Chris,

I know my response was fairly useless. I made in in the vain hope that someone at Freescale would see it and realise that filling these tables with useless, company specific acronyms only serves to keep the $%^&*'s in the marketing department happy and does nothing to assist its users.