The role of crystal oscillator in circuit

1. Provide clock signal
As a synchronization reference for digital circuits: Various operations in digital circuits, such as microprocessor instruction execution, data transmission and storage, counter counting, etc., need to be performed in precise time sequence. The stable clock signal generated by the crystal oscillator provides a unified time reference for these operations, ensuring that all parts work in coordination.
Control sequential logic circuits: In sequential logic circuits, such as triggers and registers, the clock signal determines the update time of the data. The clock pulses provided by the crystal oscillator enable these circuits to perform state transitions according to a predetermined timing, thereby realizing complex logical functions and data processing.

2. Stable operating frequency
Maintain frequency accuracy: The crystal oscillator has a high frequency stability, and the accuracy of its output frequency can usually reach tens of parts per million or even higher. This allows electronic equipment to maintain accurate operating frequencies under different operating conditions, such as temperature changes, power supply voltage fluctuations, etc., thereby ensuring stable performance of the equipment.
Ensure system performance consistency: For some applications that require high frequency accuracy, such as communication equipment and measuring instruments, a stable operating frequency is essential. Crystal oscillators can provide accurate frequency references, so that these devices can always maintain consistent performance during long-term operation, reducing signal distortion and measurement errors caused by frequency drift.

3. Synchronize multiple circuits
Coordinate the work of different modules: In complex electronic systems, there are often multiple circuit modules with different functions, such as CPU, memory, peripherals, etc. The clock signal generated by the crystal oscillator can be used as a synchronization signal to ensure the consistent working rhythm between these modules and achieve correct data transmission and interaction.
Achieve overall synchronization of the system: In some distributed systems or multi-chip systems, each part needs to be synchronized in time to ensure the normal operation of the entire system. Crystal oscillators can provide a unified clock source for these systems, and transmit the clock signal to each node through the clock distribution network to achieve overall synchronization of the system.

4. Achieve frequency synthesis
Generate multiple frequency signals: By using with other circuit elements such as dividers and multipliers, crystal oscillators can be used as a basic frequency source to generate signals of various frequencies to meet the needs of different circuit modules. For example, in a communication system, the reference frequency generated by the crystal oscillator can be used to obtain various frequency signals required for transmission and reception through frequency multiplication and division.
Meet specific frequency requirements: Some electronic devices require signals of specific frequencies to achieve specific functions, and crystal oscillators can accurately generate the required frequency signals by selecting appropriate crystals and circuit designs. For example, in audio equipment, crystal oscillators can generate accurate audio sampling frequencies to ensure high-quality processing and playback of audio signals.

5. Auxiliary timing and real-time clock functions
Provide accurate time reference: In devices that need to time or display time, such as electronic clocks, timers, calendars, etc., crystal oscillators are usually used as core components to provide accurate time references. Its stable oscillation frequency can be counted by a counter, thereby achieving accurate time measurement and display.
Support real-time clock circuit: Real-time clock (RTC) circuits usually use low-frequency crystal oscillators, such as 32.768kHz, to provide accurate time and date information for the system. Even when the device is powered off, the backup battery in the RTC circuit can maintain the operation of the crystal oscillator to ensure the continuity and accuracy of the time.