CN111708299A - A control motherboard and its design method, and an intelligent electric tool - Google Patents

Abstract

The invention belongs to the technical field of electronic circuits, and provides a control motherboard, a design method thereof, and an intelligent electric tool. The control motherboard includes a main control circuit, a timing circuit and at least two switch circuits, and the main control circuit controls one of the switch circuits to be turned on To select a preset time, and output a certain timing signal to the timing circuit every preset time, when the timing circuit receives the timing signal, it will be reset to zero, and the timing will be re-timed. If the timing signal is not received within the preset time range, it will output The reset signal is sent to the main control circuit, so that the main control circuit is reset, so as to maintain the control of the external equipment to continue to work. In this way, the main control circuit can be reset when it crashes in any state, so that the system can continue to be in an effective running state, which solves the problem that the traditional technology exists that the central processing unit cannot be reset when it crashes during operation or sleep, resulting in the system Unable to continue working.

Description

A control motherboard and its design method, and an intelligent electric tool

technical field

The invention belongs to the technical field of electronic circuits, and in particular relates to a control motherboard and a design method thereof, and an intelligent electric tool.

Background technique

The existing microcontroller unit (Microcontroller Unit, MCU) generally has a built-in watchdog, or uses an external watchdog.

However, the built-in watchdog in the MCU is not reliable, and the reasons for its failure include:

(1) Since the clock of the watchdog is not independent, the counting clock and the system are the same frequency division link, so the watchdog cannot continue to operate effectively when there is a problem with the system;

(2) Since the clock can be set by software, when the startup fails, the startup clock may be in neutral, and the watchdog cannot take effect without a clock;

(3) Some watchdogs need to be set or started by software, so after the startup fails, the initialization program is not activated, and the central processing unit (CPU) may jump to random code, so that the watchdog is disabled.

If an external watchdog is used, the dog feeding time is generally fixed. In order for the watchdog to respond in time, the dog is usually fed every 1 or 2 seconds; however, many handheld devices have precious power. For low power consumption, the MCU immediately enters sleep mode after completing the current task, while the sleeping The MCU cannot feed the dog, so the external watchdog must be turned off before the MCU sleeps. Once the MCU crashes during sleep, the entire board (the entire system) fails.

Therefore, in the conventional technology, there is a problem that the central processing unit cannot be reset even if it crashes during operation or sleep, resulting in the inability of the system to continue to operate.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a control board, a design method thereof, and an intelligent power tool, which aims to solve the problem that the central processing unit cannot be reset even if it crashes during operation or sleep, and the system cannot continue to operate. .

A first aspect of the present invention provides a control motherboard for electrically connecting with external devices, the control motherboard comprising:

at least two switch circuits, the switch circuits are used to turn on or off, and at most only one of the switch circuits is in the on state;

The main control circuit is connected to the external device and at least two of the switch circuits, controls one of the switch circuits to conduct conduction to select a preset time, and outputs a certain timing signal every preset time, and also uses for resetting according to the received reset signal to maintain control of the external device; and

a timing circuit, connected to the main control circuit and at least two switch circuits, for clearing and re-timing when the timing signal is received, if the timing signal is not received within the preset time range , the reset signal is output to the main control circuit.

Thereby, the main control circuit can be reset in any state when it crashes, so that the system is continuously in an effective running state.

In one embodiment, each of the switch circuits includes:

Resistors, switches and capacitors;

The first end of the resistor is grounded with the input end of the switch tube, the second end of the resistor is connected to the controlled end of the switch tube and is connected to the main control circuit, and the output of the switch tube The first end of the capacitor is terminated, and the second end of the capacitor is connected to the timing circuit. This embodiment defines the type selection characteristics of the switch circuit, which mainly uses a switch tube to turn on or turn off.

In one embodiment, the switch tube includes a field effect transistor or a triode;

The gate, source and drain of the field effect transistor correspond to the controlled end, the input end and the output end of the switch tube respectively;

The base, collector and emitter of the triode correspond to the controlled end, the input end and the output end of the switch tube respectively. This embodiment specifically defines that the switch tube is a field effect transistor or a triode.

In one embodiment, the main control circuit includes a main control chip;

The enable pin of the main control chip is connected to the switch circuit for controlling the switch circuit to be turned on or off; the reset pin of the main control chip is connected to the timing circuit for receiving the reset signal; the output pin of the main control chip is connected to the timing circuit for outputting the timing signal to the timing circuit. This embodiment defines the selection characteristics of the main control circuit.

In one embodiment, the timing circuit includes a watchdog chip;

The input pin of the watchdog chip is connected to the switch circuit for setting different preset times; the output pin of the watchdog chip is connected to the main control circuit for outputting the reset signal to the main control circuit. This embodiment defines the selection characteristics of the timing circuit.

In one of the embodiments, further comprising a power supply circuit;

It is connected to the timing circuit and the main control circuit, and is used for supplying power to the timing circuit and the main control circuit. Therefore, the power supply circuit is used to supply power to the timing circuit and the main control circuit, so that the control board can operate normally.

A second aspect of the present invention provides an intelligent power tool, comprising:

external devices, in particular motors and sensors; and

As described above, the control board is used to control the external device to work.

Therefore, the main control circuit in the intelligent electric tool can be reset in any state if it crashes, so that the motor and the sensor are continuously in an effective running state.

A third aspect of the present invention provides a design method for a control motherboard, including:

At least two switch circuits are used to turn on or off, and at most only one of the switch circuits is in an on state;

A main control circuit is used to control one of the switch circuits to be turned on to set a first preset time, and output a certain timing signal every the first preset time;

When the timing circuit receives the timing signal, it is reset to zero, and the timing is re-timed. If the timing signal is not received within the first preset time range, a reset signal is output, so that the main control circuit can reset.

Thereby, the main control circuit can be reset in any state when it crashes, so that the system is continuously in an effective running state.

In one embodiment, it also includes:

The main control circuit is used to switch another one of the switch circuits to conduct conduction to set a second preset time, after which the timing signal is output every second preset time, wherein the second preset time is less than the first preset time. The main control circuit is used to switch another one of the switch circuits to conduct conduction to set a second preset time, output the timing signal every second preset time range, and transmit the timing signal, wherein the The second preset time range is smaller than the first preset time range. When a reset occurs, the preset time range is reduced to increase the reliability of the control board.

In one embodiment, it also includes:

According to different time periods in a day, the first preset time is changed, and another one of the switch circuits is switched on by the main control circuit to be turned on to set different preset times. Users can choose different timing signal sending intervals according to different time periods, which not only saves energy and meets low power consumption requirements, but also greatly increases reliability.

The present invention provides a control board, a design method thereof, and an intelligent electric tool. The control board includes a main control circuit, a timing circuit and at least two switch circuits. The main control circuit controls one of the switch circuits to conduct conduction to select a preset time. , and output a certain timing signal to the timing circuit every preset time. When the timing circuit receives the timing signal, it will be cleared and re-timed. If the timing signal is not received within the preset time range, it will output a reset signal to the main control. circuit to reset the main control circuit to maintain the control of the external equipment to continue to work. In this way, the main control circuit can be reset in any state if it crashes, so that the system can continue to be in an effective running state, which solves the problem that in the traditional technology, the central processing unit cannot be reset if it crashes during operation or sleep, resulting in the system Unable to continue working.

Description of drawings

FIG. 1 is a schematic structural diagram of a module of a control motherboard according to an aspect of the present invention.

FIG. 2 is a schematic structural diagram of another module of a control motherboard according to an aspect of the present invention.

FIG. 3 is an example circuit diagram corresponding to a control motherboard provided in FIG. 1 .

FIG. 4 is a schematic flowchart of a step of a method for designing a control motherboard provided by another aspect of the present invention.

FIG. 5 is a schematic flowchart of another step of a method for designing a control motherboard according to another aspect of the present invention.

Detailed ways

In order to make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention, but not to limit the present invention.

FIG. 1 shows a module structure of a control motherboard provided by an aspect of the present invention. For the convenience of description, only the parts related to this embodiment are shown, and the details are as follows:

A control mainboard is used for electrical connection with an external device 104 , and the control mainboard includes a main control circuit 103 , a timing circuit 101 and at least two switch circuits 102 .

Among them, the switch circuit 102 is used to turn on or off, and at most one switch circuit 102 is in the on state; the main control circuit 103 is connected to the external device 104 and at least two switch circuits 102 and controls one of the switch circuits 102 It is turned on to set the preset time; after the preset time is set, the main control circuit 103 outputs a certain timing signal to the timing circuit 101 every preset time, and the timing circuit 101 clears it when it receives the timing signal, And re-timing, if the timing signal is not received within the preset time range, the reset signal is output to the main control circuit 103 to reset the reset signal received by the main control circuit 103 to maintain the control of the external device 104 to continue to work.

In this way, the main control circuit 103 can be reset when it crashes in any state, so that the system continues to be in an effective running state. The external device 104 is for the control motherboard, and the external device 104 is driven by the control motherboard. In the control board, the timing circuit 101 is provided separately from the main control circuit 103 .

Specifically, at least two switch circuits 102 are provided, and the user can set different preset times by controlling the corresponding switch circuits 102 to be turned on and off according to specific needs. After the preset time is set, the main control circuit 103 It is sufficient to output the timing signal to the timing circuit 101 within the set time, and the flexibility is high, and the reliability of the control board is strong.

FIG. 2 shows another module structure of a control motherboard provided by an aspect of the present invention. For the convenience of description, only the parts related to this embodiment are shown, and the details are as follows:

On the basis of the embodiment shown in FIG. 1 , the control board further includes a power supply circuit 105 connected to the timing circuit 101 and the main control circuit 103 for supplying power to the timing circuit 101 and the main control circuit 103 . Therefore, the power supply circuit 105 is used to supply power to the timing circuit 101 and the main control circuit 103, so that the control board operates normally.

Specifically, the power supply circuit is implemented by a DC power supply having a preset voltage value, and the preset voltage value ranges from 5V to 12V.

FIG. 3 shows an example circuit corresponding to a control board provided in FIG. 1 . For the convenience of description, only the parts related to this embodiment are shown, and the details are as follows:

FIG. 3 shows two switch circuits 102. As an embodiment of the present invention, each of the above switch circuits 102 includes a resistor, a switch tube and a capacitor (one of the switch circuits 102 includes a resistor R6, a switch tube Q1 and a capacitor C2, and the other A switch circuit 102 includes a resistor R7, a switch tube Q2 and a capacitor C3);

The first end of the resistor is grounded with the input end of the switch tube, the second end of the resistor is connected to the controlled end of the switch tube and is connected to the main control circuit 103, the output end of the switch tube is connected to the first end of the capacitor, and the first end of the capacitor is connected. The two terminals are connected to the timing circuit 101 . By setting different capacitance values of the capacitor, the time for receiving the timing signal can be changed.

Exemplarily, the switch tube includes a field effect transistor or a triode;

The gate, source and drain of the FET correspond to the controlled end, the input end and the output end of the switch tube respectively;

The base, the collector and the emitter of the triode correspond to the controlled end, the input end and the output end of the switch tube respectively.

As an embodiment of the present invention, the above-mentioned main control circuit 103 includes a main control chip; the enable pin of the main control chip is connected to the switch circuit 102 , and one enable pin corresponds to one switch circuit 102 for controlling the corresponding switch circuit 102 On or off; the reset pin of the main control chip is connected to the timing circuit 101 for receiving the reset signal; the output pin of the main control chip is connected to the timing circuit 101 for outputting the timing signal to the timing circuit 101 .

As an embodiment of the present invention, the above-mentioned timing circuit 101 includes a watchdog chip; the input pin of the watchdog chip is connected to the switch circuit 102 for setting a preset time; the output pin of the watchdog chip is connected to the main control circuit 103 , for outputting the reset signal to the main control circuit 103 . In this embodiment, an external watchdog is used to realize that the MCU can be reset in any state of crash.

Exemplarily, the timing circuit 101 adopts a watchdog chip, and the main control circuit 103 needs to give a dog feeding signal to the timing circuit 101 in time within a preset time.

The present invention also provides an intelligent power tool, comprising an external device and the above-mentioned control mainboard; wherein, the external device is specifically a motor and a sensor, and the control mainboard is used to control the external device to work.

Therefore, the main control circuit 103 in the smart power tool can be reset in any state when it crashes, so that the motor and the sensor are continuously in an effective running state. Intelligent electric tools include any one of intelligent electric skateboards, intelligent electric scooters, intelligent electric bicycles, intelligent electric strollers, electric balance cars, intelligent electric wheelchairs and electric motorcycles, and the motors and sensors are set inside the intelligent electric tools , when the control board drives the motor to rotate, the motor will drive the smart power tool to move; the sensors include ranging sensor, infrared sensor and acceleration sensor. The main board controls the smart electric tool to stop moving, the infrared sensor is used to receive instructions through infrared rays and feed it back to the control board, and the acceleration sensor is used to obtain the acceleration information of the movement of the smart electric tool.

It should be noted that the intelligent power tool adds external devices on the basis of the above-mentioned control motherboard, so the function description and principle explanation of the timing circuit 101 , the switch circuit 102 , the main control circuit 103 and the power supply circuit 105 in the control motherboard Reference may be made to the embodiments in FIG. 1 to FIG. 3 , which will not be described in detail here.

FIG. 4 shows a step flow of a method for designing a control motherboard provided by another aspect of the present invention. For convenience of description, only the part related to this embodiment is shown, and the details are as follows:

Another aspect of the present invention also provides a method for designing a control motherboard, comprising the following steps:

S100. At least two switch circuits are used to turn on or off, and at most only one switch circuit is in the on state;

S200. Use the main control circuit to control one of the switch circuits to be turned on to set a first preset time, and output a certain time signal every first preset time range;

S300. Use the timing circuit to clear the timing signal when it receives the timing signal, and re-time. If the timing signal is not received within the first preset time range, output a reset signal to make the main control circuit reset.

Thereby, the main control circuit can be reset in any state when it crashes, so that the system is continuously in an effective running state.

FIG. 5 shows another step flow of a method for designing a control motherboard provided by another aspect of the present invention. For convenience of description, only the parts related to this embodiment are shown, and the details are as follows:

As an embodiment of the present invention, on the basis of the embodiment of the design method shown in FIG. 4 , the following steps are further included:

S400. Use the main control circuit to switch another switch circuit for conduction to set a second preset time, and then output a timing signal every second preset time, wherein the second preset time range is smaller than the first preset time scope.

Therefore, when the reset occurs, the preset time range for sending the timing signal is reduced, the reliability of the control board is increased, and the switch circuit can be switched flexibly.

Of course, the above-mentioned design method further includes: according to different time periods in a day, switching another switch circuit to be turned on by the main control circuit to change the first preset time.

The user can set the interval sending time of the timing signal according to different time periods, for example: at 8:00-20:00 in the 24-hour format, set the first preset time range to 5 seconds, during the working hours during the day The preset time is relatively short, which enables the device to respond to abnormal situations in a timely manner; at 20:00-8:00 in a 24-hour clock, the first preset time range is set to 5 hours. The device can sleep within 5 hours. The device wakes up to feed the dog just before the 5 hours, and then continues to sleep, and restarts the timer for the next 5 hours. This saves precious battery power.

Therefore, setting the first preset time range according to the actual demand not only saves energy and meets the requirement of low power consumption, but also greatly increases the reliability.

Below in conjunction with Fig. 1-Fig. 5, the above-mentioned one kind of control motherboard and its design method, the working principle of the intelligent electric tool are described as follows:

The formula for setting the time of the external watchdog IC is as follows:

For extended Versions SGM820B-X:

t _{WD_extended} (ms)=78.3×C _CWD (nF)+51 (ms)

1) T=78.3*68+51=5.3 seconds.

When working, you need to set the dog feeding time to 5 seconds. The MCU drives the 68NF_ON pin to pull up and the 220uF_ON pin to pull down, so that the switch Q2 is turned on, and the capacitor C3 (68nF) is connected to the watchdog circuit. The branch of the capacitor C2 and the switch Q1 is disconnected. Within 5 seconds of timing, the MCU will give a dog feeding signal. Once the machine crashes, the watchdog WDO pin will output a low pulse signal to nMR (manual reset) at the end of 5 seconds, and then the RESET_TO_MCU pin will output a low pulse signal. Give the MCU a low pulse to reset the MCU.

2) T=78.3*220*1000+51=17226.051s=4.785hours.

When sleeping, you need to set the dog feeding time to 5 hours. The MCU drives the 220uF_ON pin to pull up and the 68NF_ON pin to pull down, so that the switch Q1 is turned on, and the capacitor C2 (220uF) is connected to the watchdog circuit. The branch of the capacitor C3 and the switch Q2 is disconnected. Before the timing time of 5 hours, the MCU will wake up once and give the dog feeding signal. Once it crashes, the WDO pin of the watchdog will output a low pulse signal at the end of 5 hours to nMR (manual reset), and then The RESET_TO_MCU pin will give the MCU a low pulse to reset the MCU.

3) Usually, the MCU working time period uses 5 seconds to feed the dog, adjust the dog feeding time to 5 hours before going to sleep, and then go to sleep. The MCU wakes up to feed the dog a moment before 5 hours (re-timed for 5 hours), then immediately goes to sleep. If the MCU is woken up abnormally during sleep, it will be changed to the 5-second dog feeding time, and it will work normally to determine whether it is necessary to respond and deal with other matters. ) to enter sleep mode. In this way, no matter the working mode or the sleep mode, there is an external watchdog to protect it, which not only saves energy and meets the requirements of extremely low power consumption, but also greatly increases the working reliability of the MCU and the whole board.

After 5 hours, the watchdog IC gives a reset pulse, and at the same time, the 220uF capacitor voltage is cleared and the next 5-hour timing is performed again. The dog feeding time of 5 seconds and 5 hours can be switched at will.

4) It can be seen that the MCU can be protected by an external watchdog whether it is sleeping or working. Even if an abnormality occurs, the MCU can be pulled back to the normal working mode.

To sum up, the embodiment of the present invention provides a control motherboard, a design method thereof, and an intelligent power tool. The control motherboard includes a main control circuit, a timing circuit, and at least two switch circuits. The main control circuit controls one of the switch circuits to turn on to Select the preset time, and output a certain timing signal to the timing circuit every preset time. When the timing circuit receives the timing signal, it will be cleared and re-timed. If the timing signal is not received within the preset time range, the output will be reset. The signal is sent to the main control circuit to reset the main control circuit to maintain the control of the external equipment to continue to work. In this way, the main control circuit can be reset in any state if it crashes, so that the system can continue to be in an effective running state, which solves the problem that in the traditional technology, the central processing unit cannot be reset if it crashes during operation or sleep, resulting in the system Unable to continue working.

The above descriptions are only preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent replacements and improvements made within the spirit and principles of the present invention shall be included in the protection of the present invention. within the range.

Claims (10)

1. A control mainboard, for being electrically connected with external equipment, it is characterized in that, described control mainboard comprises: at least two switch circuits, the switch circuits are used to turn on or off, and at most only one of the switch circuits is in the on state; The main control circuit is connected to the external device and at least two of the switch circuits, controls one of the switch circuits to be turned on to select a preset time, and outputs a certain timing signal every preset time, and is also used for receiving to reset the reset signal to maintain control of the external device; and a timing circuit, connected to the main control circuit and at least two switch circuits, for clearing and re-timing when the timing signal is received, if the timing signal is not received within the preset time range , the reset signal is output to the main control circuit. 2. The control board according to claim 1, wherein each of the switch circuits comprises: Resistors, switches and capacitors; The first end of the resistor is grounded with the input end of the switch tube, the second end of the resistor is connected to the controlled end of the switch tube and is connected to the main control circuit, and the output of the switch tube The first end of the capacitor is terminated, and the second end of the capacitor is connected to the timing circuit. 3. The control board according to claim 2, wherein the switch tube comprises a field effect transistor or a triode; The gate, source and drain of the field effect transistor correspond to the controlled end, the input end and the output end of the switch tube respectively; The base, collector and emitter of the triode correspond to the controlled end, the input end and the output end of the switch tube respectively. 4. The control motherboard according to claim 1, wherein the main control circuit comprises a main control chip; The enable pin of the main control chip is connected to the switch circuit for controlling the switch circuit to be turned on or off; the reset pin of the main control chip is connected to the timing circuit for receiving the reset signal; the output pin of the main control chip is connected to the timing circuit for outputting the timing signal to the timing circuit. 5. control mainboard as claimed in claim 1, is characterized in that, described timing circuit comprises watchdog chip; The input pin of the watchdog chip is connected to the switch circuit for setting different preset times; the output pin of the watchdog chip is connected to the main control circuit for outputting the reset signal to the main control circuit. 6. The control board of claim 1, further comprising a power supply circuit; It is connected to the timing circuit and the main control circuit, and is used for supplying power to the timing circuit and the main control circuit. 7. An intelligent power tool, characterized in that, comprising: external devices, in particular motors and sensors; and The control mainboard according to any one of claims 1-6, wherein the control mainboard is used to control the external device to work. 8. A design method for a control motherboard, characterized in that, comprising: At least two switch circuits are used to turn on or off, and at most only one of the switch circuits is in an on state; A main control circuit is used to control one of the switch circuits to be turned on to set a first preset time, and output a certain timing signal every the first preset time; When the timing circuit receives the timing signal, it is reset to zero, and the timing is re-timed. If the timing signal is not received within the first preset time range, a reset signal is output, so that the main control circuit can reset. 9. The design method of claim 8, further comprising: The main control circuit is used to switch another one of the switch circuits to conduct conduction to set a second preset time, after which the timing signal is output every second preset time, wherein the second preset time is less than the first preset time. 10. The design method of claim 8, further comprising: According to different time periods in a day, the first preset time is changed, and the other one of the switch circuits is switched on by the main control circuit to set different preset times.

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