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The crystal oscillator circuit of the single-chip microcomputer is a very important part of the single-chip microcomputer system. In the single-chip microcomputer, the crystal oscillator is like the heart of the single-chip microcomputer. If there is no heart beating, the single-chip microcomputer cannot work, which directly affects the clock signal and operation stability of the single-chip microcomputer.
In the single-chip microcomputer system, the crystal oscillator circuit plays the role of providing the clock signal, and the clock signal is the basis for the single-chip microcomputer to perform calculations, control and communication.
The basic principle of the passive crystal oscillator circuit is to use the piezoelectric effect of the crystal to generate a stable clock signal. The crystal oscillator circuit consists of a crystal resonator, an amplifier and a compensation circuit.
First of all, the crystal resonator is the core part of the crystal oscillator circuit, which consists of a crystal and a load capacitor. The crystal is a piezoelectric element that can generate mechanical vibrations. When an electric field is applied or mechanical vibrations are applied, the crystal will accumulate and distribute electric charges, thereby generating voltage.
The load capacitor is set to match the oscillation frequency of the crystal, which will affect the resonant frequency and stability of the crystal oscillator circuit.
(Of course, you can also find our Yangxing technical team to perform matching tests)
Active crystal oscillator external circuit The usual usage of active crystal oscillator: one pin is suspended, two pins are grounded, three pins are connected to output, and four pins are connected to voltage. Active crystal oscillator does not require the internal oscillator of the MCU, and the connection method is relatively simple.
The microcontroller is a complex synchronous timing circuit. In order to ensure the realization of the synchronization method, the circuit should work strictly according to the timing under the control of a unique clock signal. The role of the crystal oscillator is to provide a reference clock signal for the microcontroller system, similar to the instructor who shouts commands during military training. All soldiers complete the response actions under the instructor's command, such as instruction execution, data transmission, etc.
All the work inside the microcontroller is based on this clock signal. The circuit used to generate the clock signal required for the operation of the microcontroller is the clock circuit. The use of a crystal oscillator circuit can avoid the problems of instability and poor anti-interference of the built-in RC oscillator of the microcontroller, and provide a clock signal with higher precision and low jitter, thereby ensuring the reliability and stability of the system.
In addition, the crystal oscillator circuit can also adjust the frequency as needed to meet the requirements of different applications. Therefore, when designing and manufacturing a single-chip microcomputer system, the quality and stability of the crystal oscillator circuit are very important and directly related to the performance of the entire system.
