AVR-Chat

--- In AVR-Chat@yahoogroups.com, Bruce Parham <obparham@j...> wrote:
> I started playing with the watchdog timer in Studio sim and it
> does work but the timing is way off vs the data sheet specs. 

I wouldn't trust the simulator much for anything other than 
arithmetic/logic.  In my opinion, a simulator is not of much value 
when you can try things out on the "real thing" and not have to worry 
about simulation-induced errors and anomalies.  Get yourself a JTAG 
ICE device and have at it.

I have used the original JTAG ICE which I got free for attending an 
Atmel seminar.  Depending on which chip you want to use you may need 
to get a JTAG Mk II.  Although I haven't used it myself, I've heard 
good things about the ECROS Technology JTAG device which costs less 
than the one from Atmel.

http://www.ecrostech.com./Products/AvrJtagIce/Intro.htm

> Does anybody have any insights as to how the real hardware does it?
> Is it still enabled after a reset?

No, the watchdog timer is not enabled after reset.  If you look at the 
datasheet for the device you'll see that the all the bits of the WDTCR 
register have an initial value of zero.  The initial values prevail 
after any of the reset events (power on, external reset, etc.).

Don