Question on Watchdog

anshulgrover415 · ‎2004-07-28

Posted on July 28, 2004 at 14:38

anshulgrover415 · ‎2004-07-28

Posted on July 28, 2004 at 13:18

I am working on the ST7324. In the option bytes you have an option of selecting the hardware/ software watchdog. What exactly would be the difference in both these cases? Which one should we generally select?

Thanks

Aina

anshul · ‎2004-07-28

Posted on July 28, 2004 at 14:16

Hi Aina,

There is a perfect answer for you in the Knowledge Base.

What's the difference between an hardware watchdog and a software one?

Ans. An hardware watchdog is enabled immediately after reset. The software has to be enabled by software. Once enabled the WDG register has to be refreshed to avoid a reset to occur; it can no longer be disabled.

There are some more FAQ's related to watchdog, you can go to knowledge Base for more details.

Regards

Ansh

anshulgrover415 · ‎2004-07-28

Posted on July 28, 2004 at 14:21

Oh!!!!!! I had missed checking on the Knowledge Base.

Thanks for your help

Aina

anshulgrover415 · ‎2004-07-28

Posted on July 28, 2004 at 14:22

Whats the difference between the wtachdog in Lite0 and the one in 324?

anshul · ‎2004-07-28

Posted on July 28, 2004 at 14:30

Hi Aina

In ST72(F)324 the watchdog timer is a programmable free-running downcounter. And the timeout period varies from 1.496msec to 128.552msec.

In Lite0 the normal watchdog timeout period is 2msec (@8MHz Fcpu) after which it generates a reset. Here the watchdog is running with the Lite Timer.

Best Regards

Ansh

anshulgrover415 · ‎2004-07-28

Posted on July 28, 2004 at 14:34

What about the other ST7 devices. Which Watchdog is present in them?

anshul · ‎2004-07-28

Posted on July 28, 2004 at 14:37

Hi Aina

The Lite Timer based Watchdog is only present in ST72FLite0.

On all the other devices, it is the 7-bit timer watchdog. But the timeout range varies for different MCU's. The timeout period depends upon the watchdog presaclar in the device. You can refer the datasheet of the particular MCU for this information.

Best Regards

Ansh

anshulgrover415 · ‎2004-07-28

Posted on July 28, 2004 at 14:38

Thanks a lot Ansh for you help

Aina