RC oscillation frequency is mainly influenced by the following conditions:

1.RC oscillator voltage, different voltage will affect RC oscillator frequency. when in high operating frequency, users should pay attention to the system operating voltage, if operating voltage is too low, the system will possibly work in unstable state, especially for battery-powered systems;

2.Operating ambient temperature, different temperature will also affect the RC oscillator frequency;

3.External interference sources, different RC combinations will have different noise filter performance, PCB layout can also improve the stability of RC oscillation, Capacitor (C) should be connected to MCU ground and should not be directly connected to external circuit.