A fast reset circuit for MCU crashes

Abstract

This utility model relates to the field of electronic product technology, specifically to a fast reset circuit for an MCU that has crashed. The fast reset circuit includes a timer chip U1, with pin 1 connected to an external button and pin 6 connected to the MCU's reset pin NRST. The external button is used to input a trigger signal to pin 1 of the timer chip U1. When the external button is continuously pressed for a preset time, pin 6 of the timer chip U1 outputs a low-level signal, pulling the MCU's reset pin NRST low, thus achieving a hardware reset. This pure hardware reset, achieved through an external button and timer chip, eliminates the need to disassemble the device casing, avoiding the structural damage of traditional reset methods. The long-press trigger mechanism and automatic timer reset function effectively prevent accidental operation, ensuring that the reset is triggered only under strict conditions.

Description

Technical Field

[0001] This utility model relates to the field of electronic product technology, specifically to a fast reset circuit for MCU crashes. Background Technology

[0002] A microcontroller unit (MCU), also known as a single-chip microcomputer or microcontroller, is a chip-level computer that integrates a central processing unit (CPU) with a reduced frequency and specifications, along with peripheral interfaces such as memory, counters, USB, A / D converters, UART, PLC, DMA, and even LCD driver circuits, onto a single chip. This allows for different combinations of control for various applications.

[0003] In existing technologies, the MCU, as the core control unit of electronic devices, often crashes due to program vulnerabilities, external interference, or abnormal operation. Traditional reset methods include:

[0004] Software reset: Reset is triggered by program instructions, but it cannot be executed when the MCU is completely frozen.

[0005] Hardware reset: This requires physical operation (such as disconnecting the power supply or shorting the reset pin), but most devices are enclosed designs, and the reset operation requires disassembling the casing, which can cause structural damage and increase maintenance costs. Utility Model Content

[0006] This invention addresses the technical problems existing in the prior art by providing a fast reset circuit for MCU crashes, thus solving the problems of difficulty in quickly resetting MCU crashes and the complexity of the reset operation.

[0007] The technical solution of this utility model to solve the above-mentioned technical problems is as follows: a fast reset circuit for MCU crashes, comprising:

[0008] The timer chip U1 has pin 1 connected to an external button and pin 6 connected to the MCU's reset pin NRST.

[0009] The external button is used to input a trigger signal to pin 1 of the timer chip U1;

[0010] When the external button is pressed continuously for a preset time, pin 6 of the timer chip U1 outputs a low-level signal, which pulls the MCU's reset pin NRST low to achieve a hardware reset.

[0011] Based on the above technical solution, the present invention can be further improved as follows.

[0012] Furthermore, the external button performs a non-reset function when pressed briefly, and the short press operation will not trigger the timing of the timer chip U1.

[0013] Furthermore, the timer chip U1 automatically resets the timer after the button is released for less than a preset time, and restarts the timer when the button is pressed again.

[0014] Furthermore, the preset time is 10 seconds.

[0015] Furthermore, the NRST reset pin of the MCU is active low;

[0016] When the NRST pin is pulled low to GND by an external circuit, the MCU immediately enters a reset state;

[0017] When the NRST pin returns to a high level, the MCU ends the reset and restarts the program.

[0018] Furthermore, one end of the external button is connected to GND, and the other end is connected in series with a pull-up resistor R1 to pin 1 of the timer chip U1.

[0019] Furthermore, it also includes a power supply filter capacitor C1, which is connected between the power supply pins VDD and GND of the timer chip U1.

[0020] Furthermore, it also includes an MCU decoupling capacitor C2, one end of which is connected to the MCU power supply pin VDD, and the other end is connected to the MCU ground pin VSS.

[0021] Furthermore, the external buttons are mechanical buttons or capacitive touch buttons.

[0022] Furthermore, the timer chip U1 is model ECJ2310040-151A-2B5B.

[0023] The beneficial effects of this utility model are:

[0024] Non-destructive high-reliability reset

[0025] A pure hardware reset is achieved through an external button combined with a timer chip, eliminating the need to disassemble the device casing and avoiding the structural damage of traditional reset methods. A long-press trigger mechanism (e.g., 10 seconds) and an automatic timer reset function effectively prevent accidental operation, ensuring that the reset is triggered only under strict conditions, with a tested success rate of up to 99.9%.

[0026] Low cost and function reuse

[0027] Using general-purpose timer chips and common peripheral components (resistors, capacitors) reduces production costs; the same button serves as both a reset button and a regular operation button, reducing the number of buttons, simplifying the design, and improving resource utilization.

[0028] User-friendly and widely applicable

[0029] Long-press time settings provide intuitive operational feedback, enhancing the user experience; support for mechanical buttons or capacitive touch buttons adapts to different device needs, balancing reliability and flexibility.

[0030] High reliability

[0031] Pure hardware circuit design with strong anti-interference ability and high reset success rate: It adopts a general-purpose timer chip and standard peripheral components, which is easy to mass-produce; the long press and short press functions are separated to avoid accidental reset due to misoperation. Attached Figure Description

[0032] Figure 1 This is the circuit diagram of this utility model. Detailed Implementation

[0033] The principles and features of this utility model are described below with reference to the accompanying drawings. The examples given are only for explaining this utility model and are not intended to limit the scope of this utility model.

[0034] like Figure 1 As shown, a fast reset circuit for an MCU crash includes:

[0035] The timer chip U1 has pin 1 connected to an external button and pin 6 connected to the MCU's reset pin NRST.

[0036] The external button is used to input a trigger signal to pin 1 of the timer chip U1;

[0037] When the external button is pressed continuously for a preset time, pin 6 of the timer chip U1 outputs a low-level signal, which pulls the MCU's reset pin NRST low to achieve a hardware reset.

[0038] Specifically, the external button performs a non-reset function when pressed briefly, and the short press operation does not trigger the timing of the timer chip U1.

[0039] The timer chip U1 automatically resets its timer after the button is released for less than a preset time, and restarts the timer when the button is pressed again. Preferably, the preset time is 10 seconds.

[0040] Specifically, the NRST reset pin of the MCU is active low;

[0041] When the NRST pin is pulled low to GND by an external circuit, the MCU immediately enters a reset state;

[0042] When the NRST pin returns to a high level, the MCU ends the reset and restarts the program.

[0043] Press and hold the button to trigger a reset:

[0044] When the MCU crashes due to a program infinite loop or external interference, the user needs to press and hold SW1 for more than a preset time (10 seconds). During this time, pin 1 (KEY) of timer chip U1 is continuously pulled low to GND, and the internal timer starts. After 10 seconds, pin 6 of U1 outputs a low-level signal, pulling the MCU's NRST pin low to GND, forcing the MCU into a reset state.

[0045] Short press the button to perform other functions:

[0046] If SW1 is pressed briefly (for less than 10 seconds), the timer chip U1 will not reach the preset value. In this case, pin 6 will remain high, and the NRST pin will not be affected. The short press operation can be recognized by the MCU as a regular input signal (such as menu selection or parameter adjustment), realizing the multiplexing of button functions.

[0047] In one implementation, one end of the external button is connected to GND, and the other end is connected in series with a pull-up resistor R1 to pin 1 of the timer chip U1. R1 (2kΩ): serves as a pull-up resistor to ensure that pin 1 of the timer chip remains at a high level when the button is not pressed.

[0048] The MCU crash quick reset circuit also includes a power supply filter capacitor C1, which is connected between the power supply pin VDD and GND of the timer chip U1.

[0049] The MCU crash quick reset circuit also includes an MCU decoupling capacitor C2, one end of which is connected to the MCU power supply pin VDD and the other end is connected to the MCU ground pin VSS.

[0050] The timer chip U1 (model ECJ2310040-151A-2B5B) has its pin 1 (KEY) connected to GND via an external button SW1, and its pin 6 connected to the MCU's reset pin NRST.

[0051] External button SW1 is connected to ground (GND) at one end and to pin 1 of timer chip U1 after being connected in series with pull-up resistor R1 (2kΩ).

[0052] The power supply filter capacitor C1 (capacitance 104) is connected in parallel between the power supply pin VDD (+3.3V) and GND of the timer chip U1;

[0053] The MCU decoupling capacitor C2 (capacitance 104) is connected in parallel between the MCU's power supply pin VDD (+3.3V) and ground pin VSS (GND).

[0054] Power stability guarantee:

[0055] The function of C1 is to filter out high-frequency noise from the power supply of the timer chip U1, preventing timing errors or false triggering caused by voltage fluctuations.

[0056] The function of C2 is to suppress transient interference in the MCU power supply and prevent the NRST pin from being accidentally pulled low due to power supply noise.

[0057] In one implementation, the external button is a mechanical button or a capacitive touch button.

[0058] Specifically, the SW1 can use mechanical buttons (such as tactile switches) or capacitive touch buttons, depending on the device requirements.

[0059] The workflow is as follows:

[0060] 1. The user presses and holds SW1 for more than 10 seconds;

[0061] 2. Timer chip U1 starts timing after detecting a continuous low-level signal;

[0062] 3. When the timer reaches 10 seconds, pin 6 of U1 outputs a low level, pulling the NRST pin low;

[0063] 4. Reset the MCU and rerun the program;

[0064] 5. If SW1 is released prematurely, U1 will be reset to zero, NRST will remain high, and the MCU will operate normally.

[0065] Actual testing showed that this circuit can stably trigger MCU reset under a 10-second long press, with a reset success rate of 99.9%. Furthermore, the short press operation does not interfere with the operation of the MCU, meeting the high reliability requirements of electronic devices.

[0066] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this utility model, "a plurality of" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0067] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. An MCU hang quick reset circuit, characterized by, include: The timer chip U1 has pin 1 connected to an external button and pin 6 connected to the MCU's reset pin NRST. The external button is used to input a trigger signal to pin 1 of the timer chip U1; When the external button is pressed continuously for a preset time, pin 6 of the timer chip U1 outputs a low-level signal, which pulls the MCU's reset pin NRST low to achieve a hardware reset.

2. The MCU hang reset circuit of claim 1, wherein, The external button performs a non-reset function when pressed briefly, and the short press operation will not trigger the timing of the timer chip U1.

3. The MCU crash quick reset circuit according to claim 2, characterized in that, The timer chip U1 automatically resets the timer after the button is released for less than a preset time, and restarts the timer when the button is pressed again.

4. The MCU crash fast reset circuit according to claim 3, characterized in that, The preset time is 10 seconds.

5. The MCU crash fast reset circuit according to claim 1, characterized in that, The NRST reset pin of the MCU is active low; When the NRST pin is pulled low to GND by an external circuit, the MCU immediately enters a reset state; When the NRST pin returns to a high level, the MCU ends the reset and restarts the program.

6. The MCU crash fast reset circuit according to claim 1, characterized in that, One end of the external button is connected to GND, and the other end is connected in series with a pull-up resistor R1 to pin 1 of the timer chip U1.

7. The MCU crash fast reset circuit according to claim 1, characterized in that, It also includes a power supply filter capacitor C1, which is connected between the power supply pin VDD and GND of the timer chip U1.

8. The MCU crash fast reset circuit according to claim 1, characterized in that, It also includes an MCU decoupling capacitor C2, one end of which is connected to the MCU power supply pin VDD and the other end is connected to the MCU ground pin VSS.

9. The MCU crash quick reset circuit according to any one of claims 1-8, characterized in that, The external buttons are mechanical buttons or capacitive touch buttons.

10. The MCU crash quick reset circuit according to any one of claims 1-8, characterized in that, The timer chip U1 is model number ECJ2310040-151A-2B5B.

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