topic MC1321x self clocked mode in 8-bit Microcontrollers

MC1321x self clocked mode

fignon — Tue, 22 Jan 2008 23:52:43 GMT

Hello,
I'm using self clocked mode(SCM) with MC1321x. It works correctly but I don't understand how the ICGFLTU and ICGFLTL register work.
Do you know where I can find a table where I can see ICDCLK frequency and the value of this register ?

Best regards.

Re: MC1321x self clocked mode

Mads — Wed, 23 Jan 2008 00:17:07 GMT

Hi,

All the documentation can be found here:

http://www.freescale.com/webapp/sps/site/prod_summary.jsp?code=MC13213&nodeId=01J4Fs25657103&fpsp=1&tab=Documentation_Tab

The ICG module is described in the Mc1321x reference manual.

(MC1321XRM)

BR,

Mads

Re: MC1321x self clocked mode

fignon — Wed, 23 Jan 2008 17:58:06 GMT

I have already read the MC1321XRM but I don't understand how varies ICDCLK frequency with ICGFLTU and ICGFLTL value.
Several tests show me it works but I don't know how.
Could you briefly explain to me how it work ?

Best regards.
fignon

Re: MC1321x self clocked mode

Mads — Thu, 24 Jan 2008 01:22:10 GMT

Fignon,

Im not an expert on this module, but the Mc1321x is simply just a HCS08 GT/GB60a and a radio.

You can find an application note for all your needs on the 8 bit microcontroller website.

E.g. is there one called AN2496
Calibrating the MC9S08GB/GT Internal Clock Generator (ICG)

I think that would help you - it even comes with source code examples.

For other application notes for 8 bit cpu's then have a look here :

http://www.freescale.com/webapp/sps/site/overview.jsp?nodeId=01624684491179

BR,

Mads

Re: MC1321x self clocked mode

RickN — Sun, 10 Feb 2008 05:31:56 GMT

Hi Fignon,

I spent some time looking through the docs, and you are right that there is very little information on the settings for the Filter Registers (FLTU, FLTL). I put in a service request and was unable to get the equation (mapping) for filter bits to clock frequency. The default value of 0x0C0 maps to approximately 8MHz. I was told to change the value and use a scope to see the result! Basically you really don't want to use the self clocked mode (SCM) for much of anything. Move over to FLL Engaged with the Internal Clock Source (FEI), and you have much better control of your MCU clocking. You can trim the internal oscillator, and you have some choices of core clock speeds. I recommend using the Internal Clock Source and going to FEI clock mode as an option for you.

Thanks,

Rick