I think it's in the settings. Mine automatically turns on at 2ft I think.2 things stood out: It does not turn on when it gets wet. Once dive I booted it up but by the time I made it to the water & got it wet, it had shut itself off & did not automatically turn on. Not a big deal but good to know. I did poke through the settings but if there's a place to change this, I didn't find it.
Again, I wonder if this is in the settings. Mine counts EDT until I'm nearly on the boat. I know this because if I'm at 99 minutes I'll hang out under the boat to get to 100!!The Peregrine counted EDT until the end of my safety stop & then stopped counting. I did not drop back below 20 FSW, possibly that might cause it to resume. Don't know. But I was at depth for an additional 5 minutes or so & the EDT did not account for this.
I'm gonna go dig up my Peregrine and see what I can find out. Make sure you give it a good warm, fresh water rinse after each dive. It helps to keep the two buttons from getting crusty and sticking.