Resolved! Why do we choose LSE capacitance low?
STM32H7B3I-DK - Discovery kit use NX3215SA-32.768KHZ-EXS00A-MU00525 Crystal. Crystal Load Capacitance is 6, 9, 12.5 pF but STM32H7B3I-DK - Discovery kit use 1.5pF. Why it use different load capacitance.