CN117472831A - A multi-MCU programming and serial port switching circuit, method and system - Google Patents

Abstract

The invention discloses a multi-MCU (micro control unit) burning and serial port switching circuit, a method and a system, and relates to the technical field of electronic circuits. The method comprises the step of controlling only one channel to be effective in each stage of sub-unit through the control signal unit so as to realize the connection between the input signal unit and any MCU unit. The invention can expand the number of MCU according to the need, and the theoretical upper limit of the number is limited only by the driving capability of the input signal unit and the bandwidth of the line.

Description

A multi-MCU programming and serial port switching circuit, method and system

Technical field

The invention relates to the field of electronic circuit technology, and in particular to a multi-MCU burning and serial port switching circuit, method and system.

Background technique

In the existing technology, there are often multiple MCUs in the circuit, so multiple programming interfaces and debugging interfaces (such as serial ports) are designed on the printed circuit board. This results in too many devices on the circuit board, which takes up space, resources and cost. As the number of interfaces increases, the number of corresponding cables increases, and the switching of interfaces also increases the workload of developers.

The Chinese patent with publication number CN114466254A discloses a serial port switching circuit and its switching method, communication management machine and communication system. Wherein, the serial port switching circuit includes an MCU, a switching circuit, a first serial port circuit with an RS485 serial port and a second serial port circuit with an RS232 serial port; the first serial port circuit and the second serial port circuit are respectively connected to the MCU, and the first serial port circuit and the second serial port circuit are respectively connected to the MCU. The serial port circuit is also respectively connected to the switching circuit; the switching circuit is used to enable the first serial port circuit and disable the second serial port circuit, or enable the second serial port circuit and disable the first serial port circuit according to the received control signal; when the switching circuit is enabled When the first serial port circuit is disabled and the second serial port circuit is disabled, communication is established between the RS485 serial port and the MCU; when the switching circuit enables the second serial port circuit and the first serial port circuit is disabled, communication is established between the RS232 serial port and the MCU. The Chinese patent with the publication number CN114281392A discloses a serial port upgrade method and system for multiple MCU slave stations, which belongs to the field of MCU upgrade technology. The method includes: initializing all MCU slave stations and setting the serial port analysis chip to read enable. After the machine obtains the upgrade frame of the corresponding slave station, it is set to write enable when sending the reply frame, and is reset to read enable immediately after the sending is completed, so that the bus multiplexed by multiple MCU slave stations can complete data sending and receiving without conflict. ; Specific to a single MCU slave station, after obtaining the complete upgrade file frame by frame, the MCU slave station then copies the upgrade file to the application project storage area. Although both patents record serial port circuits, switching circuits and MCUs, the circuit structure is complex and there are still problems such as occupying space resources and high cost.

Therefore, it is necessary to design a multi-MCU programming and serial port switching circuit, which can expand the number of MCUs in real time as needed, reduce costs, and improve work efficiency.

Contents of the invention

In view of the problems existing in the prior art, the present invention provides a multi-MCU programming and serial port switching circuit.

In order to achieve the above objects, the technical solutions adopted by the present invention are as follows:

A multi-MCU programming and serial port switching circuit includes an input signal unit, a control signal unit, a switching circuit unit and an MCU unit. The control signal unit controls the input signal unit to input the signal of the switching circuit unit, and the switching circuit unit will receive the signal Transmitted to the MCU unit, the MCU is controlled to be in a valid or invalid state through control signal transmission.

Based on the above technical solution, further, the input signal unit includes several input interfaces, and the programming signals and serial port debugging signals are transmitted through the several input interfaces.

Based on the above technical solution, further, the programming signal includes a programming clock signal and a programming data signal, and the serial port debugging signal includes a serial port sending signal and a serial port receiving signal.

Based on the above technical solution, further, the control signal unit includes several control switches, one end of each control switch is connected to power supply or ground, and the other end of each control switch is connected to the switching circuit unit.

Based on the above technical solution, further, the switching circuit unit is an analog switch, wherein the analog switch is an analog switch chip.

Based on the above technical solution, further, when the analog switch is set to one level, the number of analog switches is one, and the analog switch is provided with several first input ports, second input ports, first output ports and second Output ports, each first input port is connected to an input interface, the second input port is connected to the control signal unit, and the first output port and the second output port are connected to the MCU unit.

Based on the above technical solution, further, when the analog switch is set to multi-level, the number of analog switches is set to more than 2, the first level is one analog switch, the second level is two analog switches, and the second level is The first input port of the analog switch is connected to the first output port or the second output port of the first-level analog switch, and the second input port of the second-level module switch is connected to the first output port or the second output of the first-level analog switch. port, the first output port and the second output port are connected to the MCU unit.

Based on the above technical solution, further, the MCU unit includes several MCUs, and each output port of the last stage analog switch is connected to one MCU; and the Nth stage uses 2 ^N-1 analog switches and 2 ^{N- 1} control switch to realize programming and serial communication of 2 ^N MCUs.

Based on the above technical solution, furthermore, the switching circuit unit is an analog switching circuit.

Based on the above technical solution, further, the analog switch circuit includes a first input port, a second input port, a first output port and a second output port. One end of the first input port is connected to the input signal unit, and the other end of the first input port is connected to the input signal unit. One end is connected to the drain of the first MOS tube and the drain of the second MOS tube. The gate of the first MOS tube is connected to the first resistor, the second resistor and the gate of the third MOS tube. The source of the first MOS tube is connected to The drain of the first resistor and the third MOS transistor, and the source of the third MOS transistor are connected to the second output port; the second resistor is connected to the second input port and the gate of the fourth MOS transistor, and the source of the fourth MOS transistor is connected to ground. , the drain of the fourth MOS tube is connected to the third resistor; the gate of the second MOS tube is connected to the fourth resistor, the third resistor and the gate of the fifth MOS tube, and the source of the second MOS tube is connected to the fifth MOS tube. The drain and the fourth resistor, the source of the fifth MOS tube are connected to the first output port, and the first output port and the second output port are connected to the MCU unit; the first input port is connected to the input signal unit, and the second input port is connected to the control signal unit.

A multi-MCU programming and serial port switching method, applied to multi-MCU programming and serial port switching circuits. The switching circuit unit includes a multi-stage bidirectional dual-channel sub-unit, in which both channels of the final sub-unit are Connect one MCU unit respectively; the method includes: controlling only one channel of each sub-unit to be valid through the control signal unit, so as to realize the connection between the input signal unit and any MCU unit.

Based on the above technical solution, further, the control signal unit is set to multiple different control states. Under different control states, each control switch included in the control signal unit is in a high level state, a low level state and Any one of any level states.

A multi-MCU programming and serial port switching system includes a multi-MCU programming and serial port switching circuit.

Compared with the existing technology, the present invention has the following beneficial effects:

The invention provides a multi-MCU programming and serial port switching circuit; by setting up multi-level analog switches or using a multi-level analog switch circuit, as long as the first level uses one analog switch and one control switch, the second level uses two Analog switches and 2 control switches... The Nth level uses 2 ^N-1 analog switches and 2 ^N-1 control switches to achieve programming and serial communication of 2 ^N MCUs. That is to say, the number of MCUs can be expanded as needed. Theoretically, the upper limit of the number is only limited by the driving capability of the input signal unit and the bandwidth of the circuit. It can complete the programming and serial port debugging functions of multiple MCUs using only a single interface, reducing the number of devices on the circuit board, lowering costs, reducing developer workload, simple operation, and improving work efficiency.

Description of the drawings

Figure 1 is a flow chart of the programming and serial port switching circuit of the present invention;

Figure 2 is a circuit diagram of an analog switch used in the programming and serial port switching circuit in Embodiment 1 of the present invention;

FIG. 3 is a circuit diagram of an analog switch circuit used in the programming and serial port switching circuit in Embodiment 2 of the present invention.

Detailed ways

The present invention will be further elaborated and described below in conjunction with the accompanying drawings and specific embodiments. The technical features of various embodiments of the present invention can be combined accordingly as long as they do not conflict with each other. In order to make the above objects, features and advantages of the present invention more obvious and easy to understand, the specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, the present invention can be implemented in many other ways different from those described here. Those skilled in the art can make similar improvements without departing from the connotation of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below. The technical features in various embodiments of the present invention can be combined accordingly as long as they do not conflict with each other.

In the description of the present invention, it will be understood that when an element is referred to as being "connected" to another element, it may be directly connected to the other element or indirectly connected through the presence of intervening elements. In contrast, when an element is referred to as being "directly" connected to another element, there are no intervening elements present. In the description of the present invention, it is to be understood that the terms "first" and "second" are used for differentiating purposes only. It cannot be understood as indicating or implying the relative importance or implicitly indicating the quantity of the technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include at least one of these features.

Example 1

As shown in Figure 1, a multi-MCU programming and serial port switching circuit includes an input signal unit, a control signal unit, a switching circuit unit and an MCU unit. The control signal unit controls the input signal unit to input the signal of the switching circuit unit. The switching circuit The unit transmits the received signal to the MCU unit, and controls the MCU to be in a valid or invalid state through control signal transmission. Specifically, the input signal unit includes several input interfaces through which programming signals and serial port debugging signals are transmitted. The programming signals include programming clock signals and programming data signals, and the serial port debugging signals include serial port sending signals and serial port receiving signals. The control signal unit includes several control switches, one end of each control switch is connected to power supply or ground, and the other end of each control switch is connected to the switching circuit unit.

In one embodiment, the switching circuit unit is an analog switch, wherein the analog switch is an analog switch chip. Specifically, as shown in Figure 2, the input interface includes SWC, SWD, UART_TX and UART_RX, where SWC is the burning clock signal, SWD is the burning data signal, UART_TX is the serial port sending signal, UART_RX is the serial port receiving signal, and The arrow on the input interface points to the signal transmission direction. U29, U30, and U31 in Figure 2 are the same analog switches. SW1, SW2, and SW3 are the three control switches in the control signal unit. MCU_1, MCU_2, MCU_3, and MCU_4 represent four MCUs.

When the analog switch is set to one level, there is a number of analog switches, and the analog switch is provided with several first input ports, second input ports, first output ports and second output ports, and each first input port is connected to An input interface, the second input port is connected to the control signal unit, the first output port and the second output port are connected to the MCU unit. D1, D2, D3 and D4 in Figure 2 correspond to the first input port, the second input port, the first output port and the second output port respectively. IN1, IN2, IN3 and IN4 are the four second input ports. S1A, S2A, S3A and S4A are four first output ports, S1B, S2B, S3B and S4B are four second output ports. The first output port and the second output port are respectively connected to an MCU. The analog switch also includes a ground port and a power supply port, such as GND, VDD and other ports.

Furthermore, when the analog switch is set to multi-level, the number of analog switches is set to more than 2, the first level is one analog switch, the second level is two analog switches, and the first input port of the second level analog switch Connect the first output port or the second output port of the first-level analog switch, the second input port of the second-level module switch is connected to the first output port or the second output port of the first-level analog switch, the first output port and The second output port is connected to the MCU unit. As shown in Figure 2, an analog switch U29 is set at the first level, and two analog switches U30 and U31 are set at the second level; the MCU unit includes several MCUs, and each output port of the last level analog switch is connected to an MCU; and The Nth level uses 2 ^N-1 analog switches and 2 ^N-1 control switches to realize the programming and serial communication of 2 ^N MCUs. Among them, this circuit relies on the same analog switches U29, U30, and U31. The principle is: IN1 can control the switch of the D1 signal direction. When IN1 is in a high level state, S1A and D1 are connected, and S1B and D1 are disconnected. , the signal goes from S1A; when IN1 is low level, S1B and DI are connected, S1A and D1 are disconnected, and the signal passes through S1B, D2, D3, and D4 in the same way.

Based on the multi-MCU programming and serial port switching circuit, a multi-MCU programming and serial port switching method is implemented. The switching circuit unit includes a multi-stage bidirectional dual-channel sub-unit, in which both channels of the final sub-unit are Connect one MCU unit respectively; the method includes: controlling only one channel of each sub-unit to be valid through the control signal unit, so as to realize the connection between the input signal unit and any MCU unit. The control signal unit is set to multiple different control states. Under different control states, each control switch included in the control signal unit is in any one of a high level state, a low level state and any level state. state.

Specifically, combined with Figure 2, four input interfaces, two-level analog switches, three control switches and four MCUs are set up. Among them, there are 4 states under the control of the three control switches, namely 1, 2, 3 and 4. The following table 1 shows that in the four states, different control switches are in different states. In table 1, 0 represents SW* connected to DGND, which is a low level state; 1 represents SW* connected to VCC_3V3, also That is the high level state; * represents any level state, for example, * in Table 1 represents 0 or 1;

Table 1

state SW1 SW2 SW3 1 1 1 * 2 1 0 * 3 0 * 1 4 0 * 0

Combined with Table 1, the specific implementation process is as follows:

When the control signal unit is in state 1, when SW1 is connected to VCC_3V3 and SW2 is connected to VCC_3V3, any one of the S1A, S2A, S3A, and S4A channels of the analog switch U29 is valid, and each of S1B, S2B, S3B, and S4B The channels are all closed; any one of the S1A, S2A, S3A, and S4A channels of the analog switch U30 is valid, and each channel of S1B, S2B, S3B, and S4B is closed; the SWC, SWD, UART_TX, and UART_RX signals of the input signal unit pass through the analog Enter any one of the input ports D1, D2, D3, and D4 of the switch U29, and pass through any one of the first output ports of S1A, S2A, S3A, and S4A to reach any one of the inputs of D1, D2, D3, and D4 of the analog switch U30. port, and then reaches MCU_1 through any one of the first output ports S1A, S2A, S3A, and S4A of the analog switch U30. MCU_1 can be programmed and serially communicated, while other MCUs are in an invalid state.

When the control signal unit is in state 2, when SW1 is connected to VCC_3V3 and SW2 is connected to DGND, any one of S1A, S2A, S3A, and S4A of the analog switch U29 has a valid channel, and each of S1B, S2B, S3B, and S4B The channels are all closed; any one of the S1B, S2B, S3B, and S4B channels of the analog switch U30 is valid, and each channel of S1A, S2A, S3A, and S4A is closed; the SWC, SWD, UART_TX, and UART_RX signals in the input signal unit Enter through any one of the input ports D1, D2, D3, and D4 of the analog switch U29, and reach any one of the D1, D2, D3, and D4 of the analog switch U30 through any first output port of S1A, S2A, S3A, and S4A. input port, and then reaches MCU_2 through any second output port of S1B, S2B, S3B, S4B of analog switch U30. MCU_2 can be programmed and serially communicated, while other MCUs are in an invalid state.

When the control signal unit is in state 3, when SW1 is connected to DGND and SW3 is connected to VCC_3V3, any one of the S1B, S2B, S3B, and S4B channels of the analog switch U29 is valid, and each channel of S1A, S2A, S3A, and S4A is valid. All are closed; any channel among S1A, S2A, S3A, and S4A of the analog switch U30 is valid, and each channel among S1B, S2B, S3B, and S4B is closed; the SWC, SWD, UART_TX, and UART_RX signals in the input signal unit pass through the analog It enters any input port of D1, D2, D3, and D4 of switch U29, and reaches any input port of D1, D2, D3, and D4 of analog switch U30 through any second output port of S1B, S2B, S3B, and S4B. , and then reaches MCU_3 through any one of the first output ports S1A, S2A, S3A, and S4A of the analog switch U30. MCU_3 can be programmed and serially communicated, while other MCUs are in an invalid state.

When the control signal unit is in state 4, when SW1 is connected to DGND and SW3 is connected to DGND, any one of the channels S1B, S2B, S3B, and S4B of the analog switch U29 is valid, and each channel of S1A, S2A, S3A, and S4A is valid. All are closed; any channel among S1B, S2B, S3B, and S4B of analog switch U30 is valid, and each channel among S1A, S2A, S3A, and S4A is closed; the SWC, SWD, UART_TX, and UART_RX signals in the input signal unit pass It enters any input port of D1, D2, D3, and D4 of analog switch U29 and reaches any input of D1, D2, D3, and D4 of analog switch U30 through any second output port of S1B, S2B, S3B, and S4B. port, and then reaches MCU_4 through any second output port of S1B, S2B, S3B, and S4B of analog switch U30. MCU_4 can be programmed and serially communicated, while other MCUs are in an invalid state.

That is, as long as the first level uses 1 analog switch and 1 control switch, the second level uses 2 analog switches and 2 control switches...The Nth level uses 2 ^N analog switches and 2 ^N-1 By controlling the switch, you can achieve programming and serial communication of 2 ^N MCUs.

Example 2

As shown in Figure 1, a multi-MCU programming and serial port switching circuit includes an input signal unit, a control signal unit, a switching circuit unit and an MCU unit. The control signal unit controls the input signal unit to input the signal of the switching circuit unit. The switching circuit The unit transmits the received signal to the MCU unit, and controls the MCU to be in a valid or invalid state through control signal transmission. Specifically, the input signal unit includes several input interfaces through which programming signals and serial port debugging signals are transmitted. The programming signals include programming clock signals and programming data signals, and the serial port debugging signals include serial port sending signals and serial port receiving signals. The control signal unit includes several control switches, one end of each control switch is connected to power supply or ground, and the other end of each control switch is connected to the switching circuit unit.

In another embodiment, the switching circuit unit is an analog switching circuit. In the circuit, Q8 is the first MOS tube, Q13 is the second MOS tube, Q7 is the third MOS tube, Q12 is the fourth MOS tube; Q11 is the fourth MOS tube. Five MOS tubes, R3 is the first resistor, R4 is the second resistor, R6 is the third resistor, and R5 is the fourth resistor. The principle of combining this circuit is: when IN1 is in a high level state, Q12 is turned on, the DS pole of Q12 is turned on, R6 is grounded, R5 and R6 cause Q13 and Q11 to turn on due to the voltage division, so D1 and S1A are bidirectional Turn on, when IN1 is in low level state, D1 and S1B can be bidirectionally turned on in the same way. Replace the analog switch in Figure 2 with an analog switch circuit. Among them, combined with Figure 3, D1 in Figure 3 corresponds to the D1 position in the analog switch, IN1 corresponds to the IN1 position in the analog switch, S1A corresponds to the S1A position in the analog switch, and S1B corresponds to the S1B position in the analog switch. Other circuit connections are the same as described in Embodiment 1. Similarly, when you need to connect D2, D3, and D4, you only need to modify D1 to D2, D3, and D4, and the corresponding IN1 can be modified to IN2, IN3, and IN4, and S1A to S2A, S3A, and S4A and S1B are correspondingly modified to S2B, S3B, and S4B; the other involved MOS tubes and resistors are connected in the same way.

Specifically, as shown in Figure 3, when D1, IN1, S1A and S1B are connected, the analog switch circuit includes a first input port, a second input port, a first output port and a second output port. The first input port One end is connected to the input signal unit, the other end of the first input port is connected to the drain of the first MOS tube and the drain of the second MOS tube, and the gate of the first MOS tube is connected to the first resistor, the second resistor and the third MOS tube. The gate, the source of the first MOS tube is connected to the first resistor and the drain of the third MOS tube, the source of the third MOS tube is connected to the second output port; the second resistor is connected to the second input port and the fourth MOS tube. The gate, the source of the fourth MOS tube is connected to ground, the drain of the fourth MOS tube is connected to the third resistor; the gate of the second MOS tube is connected to the fourth resistor, the third resistor and the gate of the fifth MOS tube, and the second The source of the MOS tube is connected to the drain of the fifth MOS tube and the fourth resistor, the source of the fifth MOS tube is connected to the first output port, and the first output port and the second output port are connected to the MCU unit; the first input port is connected to Input signal unit, the second input port is connected to the control signal unit.

Example 3

Based on a multi-MCU programming and serial port switching circuit, a multi-MCU programming and serial port switching system can also be implemented.

Finally, it should be noted that the above content is only used to illustrate the technical solution of the present invention, but does not limit the protection scope of the present invention. Simple modifications or equivalent substitutions of the technical solution of the present invention by those of ordinary skill in the art do not deviate from the scope of the present invention. The essence and scope of the technical solution of the invention.

Claims (13)

1. A multi-MCU programming and serial port switching circuit, characterized in that it includes an input signal unit, a control signal unit, a switching circuit unit and an MCU unit. The control signal unit controls the input signal unit to input the signal of the switching circuit unit. The switching circuit The unit transmits the received signal to the MCU unit, and controls the MCU to be in a valid or invalid state through control signal transmission. 2. A multi-MCU programming and serial port switching circuit according to claim 1, characterized in that the input signal unit includes several input interfaces, and the programming signals and serial port debugging signals are transmitted through several input interfaces. 3. A multi-MCU programming and serial port switching circuit according to claim 2, wherein the programming signal includes a programming clock signal and a programming data signal, and the serial port debugging signal includes a serial port sending signal and a serial port switching signal. receive signal. 4. A multi-MCU programming and serial port switching circuit according to claim 1, characterized in that the control signal unit includes several control switches, one end of each control switch is connected to power or ground, and each control switch The other end of the switch is connected to the switching circuit unit. 5. A multi-MCU programming and serial port switching circuit according to claim 4, characterized in that the switching circuit unit is an analog switch. 6. A multi-MCU programming and serial port switching circuit according to claim 5, characterized in that when the analog switch is set to one level, the number of analog switches is one, and several analog switches are provided. An input port, a second input port, a first output port and a second output port, each first input port is connected to an input interface, the second input port is connected to the control signal unit, and the first output port and the second output port are connected to the MCU unit. 7. A multi-MCU programming and serial port switching circuit according to claim 6, characterized in that when the analog switch is set to multi-level, the number of analog switches is set to more than 2, and the first level is an analog switch. switch, the second stage is two analog switches, and the first input port of the second stage analog switch is connected to the first output port or the second output port of the first stage analog switch, and the second input of the second stage module switch The port is connected to the first output port or the second output port of the first-level analog switch, and the first output port and the second output port are connected to the MCU unit. 8. A multi-MCU programming and serial port switching circuit according to claim 7, characterized in that the MCU unit includes several MCUs, and each output port of the last-stage analog switch is connected to one MCU; And the Nth level uses 2 ^N-1 analog switches and 2 ^N-1 control switches to realize the programming and serial communication of 2 ^N MCUs. 9. A multi-MCU programming and serial port switching circuit according to claim 1, characterized in that the switching circuit unit is an analog switching circuit. 10. A multi-MCU programming and serial port switching circuit according to claim 9, characterized in that the analog switch circuit includes a first input port, a second input port, a first output port and a second output port. , one end of the first input port is connected to the input signal unit, the other end of the first input port is connected to the drain of the first MOS transistor and the drain of the second MOS transistor, and the gate of the first MOS transistor is connected to the first resistor, the second resistor and The gate of the third MOS tube and the source of the first MOS tube are connected to the first resistor and the drain of the third MOS tube. The source of the third MOS tube is connected to the second output port; the second resistor is connected to the second input port and The gate of the fourth MOS tube and the source of the fourth MOS tube are connected to ground, and the drain of the fourth MOS tube is connected to the third resistor; the gate of the second MOS tube is connected to the fourth resistor, the third resistor and the fifth MOS tube. The gate, the source of the second MOS tube is connected to the drain of the fifth MOS tube and the fourth resistor, the source of the fifth MOS tube is connected to the first output port, and the first output port and the second output port are connected to the MCU unit; The first input port is connected to the input signal unit, and the second input port is connected to the control signal unit. 11. A multi-MCU programming and serial port switching method, applied to multi-MCU programming and serial port switching circuits, characterized in that the switching circuit unit includes a multi-stage bidirectional dual-channel sub-unit, wherein the final sub-unit Each of the two channels is connected to an MCU unit; The method includes: controlling the signal unit to control only one channel of each sub-unit to be valid, so as to realize the connection between the input signal unit and any MCU unit. 12. A multi-MCU burning and serial port switching method according to claim 11, characterized in that the control signal unit is set to a plurality of different control states, and under different control states, the control signal unit includes Each control switch is in any one of high level state, low level state and any level state. 13. A multi-MCU programming and serial port switching system, characterized by comprising a multi-MCU programming and serial port switching circuit according to any one of claims 1-10.