Watchdog Atmega328

balou · Joined: 14 Apr 2007 Posts: 36

Hey,

The maximum time "Watchdog" is 8 sec. (Atmega328).
Want to use "Watchdog" to get an Atmega329p out of "Sleep Mode" after 60 sec.
Is this possible?

Balou.

(BASCOM-AVR version : 2.0.8.2 )

Evert :-) · Joined: 18 Feb 2005 Posts: 2165

Why with the watchdog? can't you use a regular timer.

balou · Joined: 14 Apr 2007 Posts: 36

Evert,

I want the Atmega328p 60 sec. put to sleep.
And then wake up the program without external interrupt.

Balou

EDC · Joined: 26 Mar 2014 Posts: 1135

Yes it is possible in that uC because you can ENABLE WDT (Watchdog Interrupt). It means that after 8s of sleep Watchdog, instead reset uC, at firs will jump into Watchdog Interrupt. Then you can Reset Watchdog, count some variable for +8s and VERY IMPORTANT - ENABLE WDT INTERRUPT AGAIN! Then you can Sleep uC again till 60s Very Happy

Below you have example on Mega328P (UNO) that will flash LED every 10sec.
For safety purpose WDT should not be reenabled in its own interrupt routine because if main program hang then those interrupts will be forever instead reset.

balou · Joined: 14 Apr 2007 Posts: 36

Thank EDC,

It works.

Balou.

albertsm · Joined: 09 Apr 2004 Posts: 6197 Location: Holland

good example EDC.
I like it.