How does the 9S08JS16 USB Bootloader ROM auto-detect the crystal frequency?

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How does the 9S08JS16 USB Bootloader ROM auto-detect the crystal frequency?

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wrljet
Contributor II

Subject says it all.

How does the 9S08JS16 Bootloader code auto-detect the crystal frequency?

I'd like to do that in my own code.

 

Bill

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peg
Senior Contributor IV

Hello and welcome to the fora wrljet,

 

Take a look at AN2295. It explains how this works.

 

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wrljet
Contributor II

I don't see it explained in there.

 

The clock has to be running at 48 MHz before any USB emuneration

even takes place. 

 

Bill

 

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peg
Senior Contributor IV

Sorry Bill,

 

I just assumed a serial bootloader, even though you were pretty clear.

This sort of info is not generally released. Looks like your in for some disassembly.

 

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wrljet
Contributor II

Also, FWIW, the USB Bootloader WinUSB installer for this JS16 chip won't run on Windows XP SP3.

It states it require SP2 or Vista, or higher.  Has a bug.  I reported this to Freescale but haven't heard anything back yet.

 

I was hot for this chip as soon as I read the announcement, designed and built some PCBs for it, and then had the wind go out of my sails when the provided bootloader wouldn't install.

 

I debugged the installer and wrote a small hook program that tricks the buggy installer to run on Windows XP SP3. 

 

Bill

 

 

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TurboBob
Contributor IV
they need to post the source code or a DLL for the Bootloader. 
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