The RTC based on MEMS has already passed both shock tests and vibration tests that certified by ACE-Q100. It can withstand 2900g mechanical shock (JESD22-B104C Condition-H) and 20g variable frequency vibration (JESD22-B103B Condition-1).
The DS3231M can be powered by a coin cell battery and can still maintain accurate timing even the mains are disconnected. RTCprovides information about seconds, minutes, hours, days, months, and years. It can automatically adjust the end date of the month and the leap year correction. The clock format can be 24 hours or 12 hours with AM/PM indication. It provides two programmable calendar alarms and one 1Hz square wave output. In addition, the RST check pin can be used as a key input for microprocessor reset.
Note: According to the latest Air Transport Regulations, the batteries, magnets and liquids transport will be very stringent, so the cell battery CR1220 will not come with the module any more. Please buy it from the local supermarket.