When use external RC oscillator circuit to obtain system clock, It is suggested as follows:
◆ It is suggested to use 33pf capacitor as RC oscillation capacitor, for 1 ~ 8MHz frequency, please refer to the following table (VDD=5V):

◆ RC oscillator clock configurations are as follows:

◆ It is proposed to add a 47uf capacitor to MCU power side, which can effectively improve the system stability and isolate noise outside and protect system works well.
※ Note: The above parameters are for reference only, there is a deviation in actual RC oscillation frequency due to resistance and capacitance accuracy of different parameters, For actual frequency please measured it.