S12X PLL Calculator Software

[Nabla69]

Good Morning,

I enclosed here a small beta of a software to help you with the calculation of your PLL Filter on S12 and S12X.

Do enjoy,

Alvin.

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Alban-Moderator adds: Zip files contain .exe which were checked. No known virus or trojan found.

Message Edited by Alban on 2006-08-03 10:39 AM

[Xbot]

Here's my version of the PLL calculator. Just input the desired bus and oscillator frequency and you'll be given the values for SYNR, REFDV and POSTDIV.

[kef]

Is it better than S12XE IPLL Calculator Software (from S12XE page, Software & Tools tab)? :

http://cache.freescale.com/files/microcontrollers/software/device_drivers/S12XESW.zip

[Xbot]

not even close... try osc: 16mhz and bus: 50mhz... that gave me synr: 0xf1, refdv: 0x0f and postdiv: 0x0... mine had 0xd8, 0x07 and 0 ... respectively... remember to use the lowest synr possible value.

[kef]

It turns that I used calculator v1.03, which gives synr and refdv like your calculator. And when I looked for Freescale PLL calculator to post url here, I found the link to older v1.02, which gives F1 for synr and f for refdv.

v1.03 is available on S12XE documentation tab (not software and tools):

S12XEIPLLCUGSW -- Software

http://cache.freescale.com/files/microcontrollers/doc/user_guide/S12XEIPLLCUGSW.zip

[gdszyj]

that is good

[PO220]

Hi

Thanks for this software

The S12 version proposes three choices of stability.
The S12X version requires two parameters which I don't understand : stability factor and damping factor.

How can I to know if the selected filter is rather stable or rather unstable?

Thank you in advance

[PO220]

Hi,

Is my question a bad question ?

Stability factor is 50, OK. Stability delay is 0.5ms, OK. But my filter is not stable, almost stable or extremely stable ?

Thank you

[Alban]

Hello ourson,

Here is the formula from the datasheet on what this factor is based on.

As you can see, it depends on the filter bandwidth.

Cheers,

Alban.

[NZ_Design]

Thats a great litle program. Can some one please advise on the goal for the stability factor and damining factor.

Is that meant to by high or as low as you can get it.

Obviouslt the lock time wants to be as short as possable.

[Alban]

Hello NZ-Design,

Have a look in the picture attached to my previous post.
The stability factor should be as high as possible to prevent the oscillator from being ... un-stable.

Damping of 0.9 is mentioned.
It's difficult for me to recommend a value. I mean, a value above 1 means a lower bandwidth around the fundamental frequency. (also called quality factor). It impacts the stability of the oscillator.
I would say use 0.9... Because it is in the spec...

Alban.