Method of detecting the beginning of a dive for a dive computer

The process involves updating a reference pressure value (Pref) based on ambient pressure measurement, where the value is used to detect the beginning of a dive. The value stored before being updated is saved as a protection value (Psauv) of the value (Pref) to suspect the beginning of the dive. The stored value (Pref) is replaced by the saved value (Psauv) with activation of a dive mode, if the dive beginning is confirmed.