When an RTC is replaced, attention must be paid to the parameters of crystals used previously. For example, the crystal used with the NXP PCF85063AT needs to meet 60kohm or 70kohm ESR；CL = 7 pF or CL = 12.5 pF. However, DS1337 needs to use a 6pF CL crystal with ESR smaller than 50k. Therefore, when the RTC is being replaced, whether the crystal parameters of the two RTCs are consistent needs to be checked. If not, it will be necessary to change the crystal.