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How to choose the crystal oscillator capacitor of 5 1 single chip microcomputer?
You can use 5-33pf, and generally use 15P and 30P. The size of the crystal oscillator has little effect. Commonly used 30P is used for 4M and 12M, and 1 1.0592M and 20M 24M, and there are corresponding shaping circuits in the single chip microcomputer.

The maximum frequency difference between the crystal oscillator frequency and a given nominal frequency due to all combinations of specified operating and non-operating parameters in a specified time.

The total frequency difference includes the maximum frequency difference caused by frequency temperature stability, frequency temperature accuracy, frequency aging rate, frequency power supply voltage stability and frequency load stability. Generally, it is only used when short-term frequency stability is concerned and other frequency stability indicators are not required.

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In most applications, the crystal oscillator is powered on for a long time. However, in some applications, the crystal oscillator needs to be turned on and off frequently. At this time, it is necessary to consider the index of frequency stabilization preheating time (especially for military communication stations used in harsh environments, which require frequency temperature stability ≤ 0.3 ppm (-45℃ ~ 85℃). When OCXO is used as the local oscillator, the frequency stabilization preheating time will not be less than 5 minutes, but only DTCXO is needed.

Quartz crystal oscillator is a kind of resonant device made of piezoelectric effect of quartz crystal (silicon dioxide crystal). Its basic structure is roughly as follows: a thin slice is cut from a timely crystal according to a certain orientation, silver layers are plated on its corresponding two surfaces as electrodes, leads are welded on each electrode to connect with pins, and then a package shell is added to form a quartz crystal resonator.

Baidu encyclopedia-crystal oscillator