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Help on hardware Watchdog Timers

Posted: 2006/03/17 03:43:54
by eprimetime
I do not know where else to start, so I figured I'd post somewhere, anywhere, and see if anyone has any ideas.

I own a PICMG-standard Single Board Computer. It is based on the Intel 440BX chipset. Machine is currently running ClarkConnect Linux 3.2, which is directly derived from CentOS 4.0, which is why I am posting this here.

This SBC has a hardware watchdog timer on it, so that if the CPU stops responding, the computer is automatically reset.

After over a year of trying to contact someone knowledgable at the manufacturer (A company called Mitac), I finally hit what amounted to paydirt. The person I contacted was able to hook me up with a the important parts of the user manual (jumpers, info, POST codes, headers, etc.). I've got pages 1-24, and 80-86.

The manual is what clued me in to the watchdog timer. There is a jumper to either enable or disable the watchdog, and it is also software configurable.

Unfortunately, the manual doesn't tell me what the make/model of the watchdog timer chip is. I have done some Googling, and have seen references to a built-in watchdog timer on Intel's 8xx series of chipsets, but do not know if the 440BX has one built-in, or if it would have to be a seperate chip.

What I am asking for is some guidance from anyone with any experience with watchdog timers. Where can I go for more info? Any idea what common model number might be, so that I can take my search from there? There are a LOT of chips on this board, as it has integrated LAN. LCD, video, parallel, serial, USB, DiskOnChip, and MUCH more.

Ideally, if someone can tell me if this is integrated on the chipset or would be a seperate chip, and if not what to look for on this board. If a seperate chip, what kind of packaging? Square, rectangular, how many pins likely, etc? Once I have a ballpark, I can just start googling all of the chips that are likely candidates. Doing so without knowing what a candidate chip might be would be difficult, as there is everything from 8-pin chis with unreadble printing, to the large chipset chips.


Thanks for any help you can give me!


eprimetime