CN208241642U - A kind of reset circuit based on microcontroller serial port programming - Google Patents

Abstract

The utility model proposes a reset circuit based on single-chip serial port programming, including a trigger switch and a timing control circuit; the timing control circuit includes: a reset level generation circuit and a reset pulse generation circuit; The input end and the output end of the circuit are electrically connected in one-to-one correspondence; the input end of the reset pulse generating circuit is electrically connected with the output end of the reset level generating circuit, and the output end of the reset pulse generating circuit is grounded. The reset circuit provided by the utility model based on the serial port programming of a single-chip microcomputer can reduce the cost and make the circuit more stable under the premise of realizing the reset function, and can also protect the circuit components from being damaged, improve the monitoring and debugging efficiency and the system reliability.

Description

A reset circuit based on serial port programming of single chip microcomputer

technical field

The utility model relates to the technical field of power electronics, in particular to a reset circuit based on the serial port programming of a single-chip microcomputer.

Background technique

The marine equipment monitoring and health management system based on STM32F10X single-chip microcomputer, in the process of single-chip debugging, it is necessary to program the single-chip microcomputer through serial communication or online debugging, because STM32F10X needs to reset the single-chip microcomputer during each programming or online debugging , so a special serial port programming reset circuit is designed. Considering the productization and broad market prospects of the project in the later stage, in order to save costs, it is necessary to propose an improved circuit for the current serial port programming reset circuit.

Utility model content

In view of this, the utility model proposes a reset circuit based on the serial port programming of the single-chip microcomputer. On the premise of realizing the reset function of the single-chip microcomputer, the cost can be reduced, the circuit is more stable, and the circuit elements can be protected from damage.

The technical solution of the utility model is realized in the following way: the utility model provides a reset circuit based on the serial port programming of the single-chip microcomputer, including: a trigger switch and a timing control circuit;

The timing control circuit includes: a reset level generating circuit and a reset pulse generating circuit;

The two ends of the trigger switch are electrically connected to the input end and the output end of the reset level generating circuit in one-to-one correspondence;

The input end of the reset pulse generating circuit is electrically connected to the output end of the reset level generating circuit;

Output terminals of the reset level generating circuit and the reset pulse generating circuit are both grounded.

On the basis of the above technical solution, preferably, the reset level generating circuit includes: a first capacitor and a first power supply;

The positive pole of the first power supply is electrically connected to the first connection terminal of the trigger switch and the positive pole of the first capacitor;

The negative electrode of the first capacitor is electrically connected to the second connection end of the trigger switch and the input end of the reset pulse generating circuit respectively.

More preferably, the reset pulse generating circuit includes: a second power supply, a second capacitor, a first resistor, a second resistor, a third resistor and a triode;

The positive pole of the second capacitor is electrically connected to the negative pole of the first capacitor, and the negative pole of the second capacitor is electrically connected to the first connection end of the first resistor;

The second connecting end of the first resistor is electrically connected to the first connecting end of the second resistor and the base of the triode respectively, and the collector of the triode is electrically connected to the second connecting end of the third resistor. The emitter of the triode and the second connection terminal of the second resistor are both grounded, and the first connection terminal of the third resistor is electrically connected to the positive pole of the second power supply.

On the basis of the above technical solution, preferably, the timing control circuit further includes: a first protection circuit and a second protection circuit;

The first protection circuit and the second protection circuit are respectively electrically connected to the reset pulse generating circuit;

Both the first protection circuit and the second protection circuit are grounded.

More preferably, the first protection resistor includes: a freewheeling diode and a fourth resistor connected in parallel;

The anode of the freewheeling diode and the first connection end of the fourth resistor are respectively electrically connected to the anode of the second capacitor, and the cathode of the freewheeling diode and the second connection end of the fourth resistor are both electrically connected to each other. grounded.

More preferably, the second protection circuit includes: a third capacitor;

The anode of the third capacitor is electrically connected to the collector of the triode, and the cathode of the third capacitor is grounded.

Compared with the prior art, the reset circuit based on the single-chip serial port programming of the utility model has the following beneficial effects:

(1) The utility model has reduced a socket on the traditional reset circuit, a triode and the pull-down resistance of the triode, protection resistance and a capacitor, and has increased protection resistance and negative feedback capacitance at another triode of the traditional reset circuit simultaneously;

(2) Under the premise that the reset function can be realized, the circuit structure of the utility model is simpler and the cost is saved;

(3) Compared with the traditional reset circuit, the utility model adds a protection resistor and a negative feedback capacitor. The circuit of the utility model is more stable, and at the same time, it can protect the circuit components from being damaged, which improves the monitoring and debugging efficiency and the reliability of the system sex.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings that need to be used in the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description These are only some embodiments of the utility model, and those skilled in the art can also obtain other drawings based on these drawings without creative work.

Fig. 1 is the structural representation of a kind of reset circuit based on single-chip microcomputer serial port programming of the utility model;

Fig. 2 is the structural representation of a kind of reset circuit based on single-chip microcomputer serial port programming of the utility model;

Fig. 3 is the improved circuit diagram of a kind of reset circuit based on single-chip microcomputer serial port programming of the utility model;

Fig. 4 is a circuit diagram before the improvement of the reset circuit based on the serial port programming of the single-chip microcomputer of the present invention.

Detailed ways

The technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Way. Based on the embodiments of the present utility model, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the scope of protection of the present utility model.

As shown in Figure 1, in conjunction with Figure 2 and Figure 3, a reset circuit based on single-chip serial port programming of the present utility model includes: a trigger switch, a reset level generating circuit, a reset pulse generating circuit, a first protection circuit and a second protect the circuit;

The trigger switch generates a trigger signal. Both ends of the trigger switch are electrically connected to the input end and the output end of the reset level generating circuit in one-to-one correspondence. It should be noted that: the model and performance index of each component can be selected in many ways, and the type of trigger switch can be selected in many ways, such as key switch, rotary switch, touch switch, etc. In this embodiment, key switches are used.

The reset level generation circuit controls the level change of the BOOT0 pin of the single-chip microcomputer. It includes: a first capacitor C1 and a first power supply. The anode of the first power supply is the input end of the reset level generating circuit, and the negative end of the first capacitor C1 is the output end of the reset level generating circuit. Specifically, the positive pole of the first power supply is connected to the positive pole of the first capacitor C1. The first capacitor C1 controls the level state of the BOOT0 pin of the single-chip microcomputer, and then determines the area where the program is executed after the single-chip microcomputer is reset. It should be noted that the types and performance indexes of each component can be selected in various ways. In this embodiment, the first power supply is a 3.3V external power supply, and the capacitance value of the first capacitor C1 is 0.1uF.

The reset pulse generation circuit generates a reset pulse signal to control the reset of the single chip microcomputer. It includes: a second power supply, a second capacitor C2, a first resistor R1, a second resistor R2, a third resistor R3 and a transistor V1; the anode of the second capacitor C2 is the input terminal of the reset pulse generating circuit, and the emitter of the transistor V1 is Output of the reset pulse generation circuit. Specifically, the positive pole of the second capacitor C2 is electrically connected to the negative pole of the first capacitor C1, and the negative pole of the second capacitor C2 is electrically connected to the first connection end of the first resistor R1; the second connection ends of the first resistor R1 are respectively It is electrically connected to the first connection end of the second resistor R2 and the base of the transistor V1, the collector of the transistor V1 is electrically connected to the second connection end of the third resistor R3, and the emitter of the transistor V1 is connected to the second connection end of the second resistor R2. Both connection ends are grounded, and the first connection end of the third resistor R3 is electrically connected to the positive pole of the second power supply. The second capacitor C2 generates a pulse signal to control the on or off state of the triode V1 through charging and discharging; the triode V1 generates a reset pulse by switching between the on and off states; the first resistor R1 acts as a current limiting protection for the triode V1, In order to prevent the 3.3V power supply from failing; the second resistor R2 determines the charging time of the second capacitor C2; the third resistor R3 stabilizes and adjusts the voltage and current of the base of the triode V1. It should be noted that: the model and performance index of each component can be selected in many ways. In this embodiment, the second power supply is a 3.3V external power supply, the resistance value of the first resistor R1 is 1K, the second resistor R2 and the third resistor The resistance value of R3 is 10K, the capacitance value of the second capacitor is 0.1uF, and the model of the transistor V1 is KTC9013S.

The first protection circuit protects components in the reset pulse generating circuit from being broken down or damaged by voltage. It includes: a freewheeling diode D1 and a fourth resistor R4 connected in parallel. The first connection end and the second connection end of the fourth resistor R4 are respectively the input end and the output end of the first protection circuit. Specifically, the anode of the freewheeling diode D1 and the first connection end of the fourth resistor R4 are respectively electrically connected to the anode of the second capacitor C2, and the cathode of the freewheeling diode D1 and the second connection end of the fourth resistor R4 are both grounded. The freewheeling diode D1 and the fourth resistor R4 are connected in parallel to form a loop, so that the high electromotive force generated by the fourth resistor R4 is consumed in the loop in the form of a freewheeling current, and the circuit components are protected from breakdown or burnout by the induced voltage. It should be noted that the type and performance index of each component can be selected in various ways. In this embodiment, the resistance value of the fourth resistor R4 is 51K, and the type of the freewheeling diode is LL4148.

The second protection circuit protects the normal operation of the reset pulse circuit. It includes: a third capacitor C3. The positive pole and the negative pole of the third capacitor C3 are respectively the input end and the output end of the second protection circuit. Specifically, the anode of the third capacitor C3 is electrically connected to the collector of the triode V1, and the cathode of the third capacitor C3 is grounded. The third capacitor C3 uses negative feedback to eliminate the self-excited oscillation that may be caused by the distributed capacitance inside the BJT tube, so as to ensure the normal amplification of the multi-stage amplifier. It should be noted that the types and performance indexes of each component can be selected in various ways. In this embodiment, the capacitance of the third capacitor C3 is 0.1uF.

The technical principle of the reset circuit based on the serial port programming of the single-chip microcomputer of the utility model is: on the basis of the previous circuit of the utility model, the triode V2, the resistor R5, the resistor R6, the capacitor C4, and the socket XS1 are reduced, and the diode D1 is added at the same time , capacitor C1, capacitor C3, resistor R1, resistor R4, and the trigger switch; when the trigger switch is turned on, the first power supply charges the first capacitor C1, and before the first capacitor C1 is fully charged, the voltage of the microcontroller BOOT0 is 0V. Before the first capacitor C1 is fully charged, the transistor V1 is in the cut-off state; when the trigger switch is short-circuited, the voltage of BOOT0 is at a high level at this time, and it will charge the second capacitor C2 at the same time. When the voltage across the second capacitor C2 is less than 2.6V , the triode V1 is in the conduction state, due to the charging and discharging of the second capacitor C2, the triode V1 gets a conduction pulse, the width of this pulse is 1.5T, T is the time constant, when the second capacitor C2 is charged to 2.6V, the The required time is 1.5T, that is, the RESET pin of the microcontroller generates a low-level pulse, and the width of this pulse is greater than the 50uS low-level pulse width required by the RESETY pin of the microcontroller; when the voltage across the second capacitor C2 If it is greater than 2.6V, the transistor V1 is disconnected, and the RESET signal of the microcontroller is at a high level.

The freewheeling diode D1 and the fourth resistor R4 form a loop, so that the high electromotive force generated by the fourth resistor R4 is consumed in the loop in the form of a freewheeling current, thereby protecting the components in the circuit from being damaged; the third capacitor C3 is connected in parallel with the triode Between the collector and emitter of V1, negative feedback can be used to eliminate the self-excited oscillation that may be caused by the distributed capacitance inside the BJT tube, so as to ensure the normal amplification of the multi-stage amplifier.

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 replacements, improvements, etc. made within the spirit and principles of the present utility model shall be included in the Within the protection scope of the present utility model.

Claims (6)

1. A reset circuit based on single-chip serial port programming, is characterized in that, comprises trigger switch and timing control circuit; The timing control circuit includes: a reset level generating circuit and a reset pulse generating circuit; The two ends of the trigger switch are respectively electrically connected to the input end and the output end of the reset level generating circuit in one-to-one correspondence; The input end of the reset pulse generating circuit is electrically connected to the output end of the reset level generating circuit, and the output end of the reset pulse generating circuit is grounded. 2. a kind of reset circuit based on single-chip serial port programming according to claim 1, is characterized in that, described reset level generation circuit comprises: first electric capacity and first power supply; The positive pole of the first power supply is electrically connected to the first connection terminal of the trigger switch and the positive pole of the first capacitor; The negative electrode of the first capacitor is electrically connected to the second connection terminal of the trigger switch and the input terminal of the reset pulse generating circuit respectively. 3. A kind of reset circuit based on single chip microcomputer serial port programming according to claim 2, it is characterized in that, described reset pulse generating circuit comprises: second power supply, second capacitor, first resistor, second resistor, third resistor and triode; The positive pole of the second capacitor is electrically connected to the negative pole of the first capacitor, and the negative pole of the second capacitor is electrically connected to the first connection end of the first resistor; The second connecting end of the first resistor is electrically connected to the first connecting end of the second resistor and the base of the triode respectively, and the collector of the triode is electrically connected to the second connecting end of the third resistor. The emitter of the triode and the second connection terminal of the second resistor are both grounded, and the first connection terminal of the third resistor is electrically connected to the positive pole of the first power supply. 4. A kind of reset circuit based on single-chip microcomputer serial port programming according to claim 1, is characterized in that, described timing control circuit also comprises: first protection circuit and second protection circuit; The first protection circuit and the second protection circuit are respectively electrically connected to the reset pulse generating circuit; Both the first protection circuit and the second protection circuit are grounded. 5. A kind of reset circuit based on single-chip serial port programming according to claim 3 or 4, is characterized in that, described first protection circuit comprises: freewheeling diode and the 4th resistance of parallel connection; The anode of the freewheeling diode and the first connection end of the fourth resistor are respectively electrically connected to the anode of the second capacitor, and the cathode of the freewheeling diode and the second connection end of the fourth resistor are both electrically connected to each other. grounded. 6. A kind of reset circuit based on single-chip serial port programming according to claim 3 or 4, characterized in that, the second protection circuit comprises: a third capacitor; The anode of the third capacitor is electrically connected to the collector of the triode, and the cathode of the third capacitor is grounded.