topic Re: How does the 9S08JS16 USB Bootloader ROM auto-detect the crystal frequency? in 8-bit Microcontrollers

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

wrljet — Tue, 21 Apr 2009 04:22:57 GMT

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

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

peg — Tue, 21 Apr 2009 06:54:27 GMT

Hello and welcome to the fora wrljet,

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

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

wrljet — Tue, 21 Apr 2009 09:15:04 GMT

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

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

peg — Tue, 21 Apr 2009 20:07:54 GMT

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.

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

wrljet — Tue, 21 Apr 2009 20:42:02 GMT

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

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

TurboBob — Thu, 23 Apr 2009 05:22:32 GMT

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