How to convert a perpetual calendar watch without memory function into a perpetual calendar watch with memory function?

Generally speaking, the memory function of the digital perpetual calendar wall watch is mainly controlled by the time control chip and the CR2032 memory battery, in which the time control chip mainly stores the perpetual calendar information, while the CR2032 memory battery mainly plays a certain memory function, such as the sudden power failure at home, and the digital perpetual calendar wall watch does not need to re-modulate the time after the incoming call, which is the role played by the CR2032 memory battery.