Suunto EON Core has two main views in surface and dive states: time/no deco and compass. Change the main view by pressing the middle button.
The lower right field shows multiple information including max. depth, tank pressure, timer, and while diving, also no deco and stops. You can change what is shown by pressing the lower button.
Main views can be customized. See Customize dive modes with DM5.
Suunto EON Core automatically switches between surface and dive state. If you are more than 1.2 m (4 ft) below the water level, the dive state is activated.
The following display shows Suunto EON Core when tank pressure screen is in use: