Patent ID: 7593292

Claim:
A synchronization method between an analogue display means and a volatile time counter in a multi-function electronic watch when a primary powering means powering the watch are replaced, wherein the watch includes a protected volatile memory zone including at least one fixed data zone and one variable data zone, the method including the following steps: (i) calculating a value representative of a time information item by means of a time base of the watch; (ii) storing the value in the volatile time counter; (iii) updating the value in the volatile time counter periodically as a function of the supply frequency of the time information item by the time base; (iv) synchronised display of the value representative of the time information item by the analogue display means in a first operating mode of the watch; (v) non-synchronised display of a value not representative of the time information item by the analogue display means in a second operating mode of the watch; (vi) detecting an end of life of the primary power means powering the watch; (vii) setting the analogue display means to a predetermined reference position following detection of the end of life of the primary powering means; (viii) setting the value of the volatile time counter to a predetermined reference value when the primary powering means are removed; (ix) automatic synchronization between the analogue display means and the value of the volatile time counter when the primary powering means are replaced; (x) storing the value representative of the time information item in the variable data zone; (xi) detecting a zero reset of the electronic circuit of the watch; (xii) subsequently checking whether at least one part of the data of the fixed data zone has been altered; and (xiii) if there is no alteration to the fixed data zone, validating the value representative of the time information item as being correct.