Real-Time Clock (RTC)

Ahh esp32 doesn’t have RTC. The m5stack extension gives you this RTC thing.

Synchronize with NTP.

A real-time clock (RTC) is a type of clock that keeps track of the current time even when the power is off or the main system is reset.

• It uses a small battery or other power source to maintain the time and date
• can be used to provide accurate timekeeping even when the main power is not available

RTCs are commonly used in computer systems, embedded systems, and other devices that need to keep accurate time even when not connected to a power source.

They can be used to schedule events, synchronize data, or time-stamp log files. They are also used in other applications such as time-stamping financial transactions, recording the time of an event, or scheduling a task to be executed at a later time.

The RTC chip usually have a built-in quartz crystal oscillator that maintain time accuracy, and it is also used to provide an interrupt signal that can be used to wake up the main system from a low-power state. The clock is usually implemented as an integrated circuit (IC) that communicates with the main system using a serial interface such as I2C or SPI.