In the field of digital circuits, the reset function of microcontrollers is a crucial step to ensure their normal startup and operation. The reset function mainly resets the internal state of the microcontroller to its initial state, preventing issues such as chaos, runaway, or freezing during program execution, making the system ready to accept and execute various instructions at any time. The choice of reset method directly affects the stability of the product system. This article will outline the reset methods for microcontrollers, hoping to assist fellow developers.
1. Power-On ResetPower-on reset is the most basic reset method for microcontrollers. When the system power is turned on, the microcontroller initializes, the oscillator starts working, providing the system clock, allowing the system to enter normal operating state. This reset method is simple and direct, suitable for most microcontroller systems. Its characteristic is that the reset process is synchronized with the power-on process, requiring no additional reset circuit. However, the reliability of power-on reset may be affected by external factors due to the power-on curve.
2. Watchdog ResetThe watchdog reset is an internal system reset method implemented through a self-oscillating RC timer inside the microcontroller. This reset method does not rely on external circuits or the CPU main clock; it only requires enabling the watchdog function. The timer will continue to count, and when it overflows, a reset signal will be generated to restart the microcontroller. The characteristic of the watchdog is its independence and autonomy, effectively addressing issues such as program runaway or freezing, making it suitable for systems that require long-term stable operation and high reliability.
3. LVR Low-Voltage ResetLVR (Low-Voltage Reset) is a reset method based on power supply voltage. When the system input voltage falls below the set reset voltage, the microcontroller will automatically reset. This reset method helps protect the microcontroller from the effects of low voltage environments, avoiding system instability or damage due to excessively low voltage. The characteristic of LVR reset is its rapid response and ability to effectively handle fluctuations in power supply voltage. It is suitable for systems that may experience unstable or low power supply voltage in their operating environment.
4. Peripheral Circuit ResetPeripheral circuit reset is a reset method implemented through external hardware. When the internal reset mechanism fails or software reset cannot resolve the issue, external hardware can be relied upon for reset. This reset method requires designing a dedicated reset circuit and triggering the reset operation through external signals. The characteristic of peripheral circuit reset is its flexibility and controllability, allowing customization based on actual needs. It is suitable for systems that have specific requirements for reset operations or need external intervention.
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