CN207817688U

CN207817688U - A kind of serial communication bus interface circuit of compatible different agreement

Info

Publication number: CN207817688U
Application number: CN201721724144.7U
Authority: CN
Inventors: 杜延坡; 刘传华; 王灿; 刘远锋
Original assignee: Henan Thought Rail Traffic Technology Research Institute Co Ltd
Current assignee: Henan Thought Rail Traffic Technology Research Institute Co Ltd
Priority date: 2017-12-12
Filing date: 2017-12-12
Publication date: 2018-09-04
Anticipated expiration: 2027-12-12

Abstract

The utility model provides a kind of serial communication bus interface circuit of compatible different agreement, it is characterised in that：Including multiple and different protocol conversion circuitries, the plurality of different protocol conversion circuitry is communicated with same expansion interface, and the plurality of different protocol conversion circuitry connects same bus interface by mode setting circuit；Mode setting circuit includes the on-off switch being arranged on the connecting line of each protocol conversion circuitry and same bus interface.The utility model carries out the conversion between each interface by mode setting circuit, greatly improve the durability of serial communication bus hardware circuit, and can arbitrarily it switch between RS232, RS485 and RS422, increase the application range of bus interface, the interface quantity of hardware design is decreased simultaneously, cost of hardware design is reduced, and has been greatly saved the hardware development time.

Description

A kind of serial communication bus interface circuit of compatible different agreement

Technical field

The utility model is related to a kind of extension multiplex circuit of bus interface more particularly to a kind of compatible different communication protocols Serial communication bus Interface Expanding circuit.

Background technology

Bus is the set of various signal wires, is transmission data, address and control signal between each module of internal system Public passage.Serial communication bus is one kind of bus, it refer between system host and peripheral hardware and system host and host it Between utilize data line, one ground of data is transmitted successively.

Serial communication bus exchanges information between being commonly utilized in system, at present more commonly used serial communication bus have CAN, USB, RS232, RS485, RS422 etc., each communication bus have respective standard and communication protocol, different bus hardware interface Difference, and it is also incompatible each other.

Current serial communication bus interface is primarily present as following drawbacks：

1. serial communication bus interface standard type is more, incompatible between each other；

2. serial communication bus interface hardware circuitry is different；

3. bus interface circuit poor compatibility is only used for a kind of fixed communication mould with serial communication bus interface all the way Formula, if replacing communication pattern, it is necessary to redesign hardware circuit and bus interface.

Utility model content

The utility model provides a kind of serial bus interface design method for supporting multibus agreement, utilizes same hardware electricity Road and interface realize different serial bus communication modes, and can switch between different bus protocols, solve the prior art The middle problem.

The utility model uses following technical scheme：

A kind of serial communication bus interface circuit of compatible different agreement, including multiple and different protocol conversion circuitries, institute It states multiple and different protocol conversion circuitries to communicate with same expansion interface, and the plurality of different protocol conversion circuitry passes through Mode setting circuit connects same bus interface；

The mode setting circuit includes being arranged on the connecting line of each protocol conversion circuitry and same bus interface On-off switch.

The mode setting circuit tie jumper or toggle switch.

The protocol conversion circuitry includes RS485 conversion circuits, RS422 conversion circuits, RS232 conversion circuits.

The RS232 conversion circuits pass through the ports TXD and RXD port communications of mode switching circuit and bus interface, institute It is logical by the ports TX+ of mode switching circuit and bus interface, the ports TX-, the ports RX+, the ports RX- to state RS422 conversion circuits Letter, the RS485 conversion circuits pass through the ports RS485+ of mode switching circuit and bus interface, RS485- port communications.

The RS485 conversion circuits are directly connected to the ports RS485+ of bus interface, while RS485 conversion circuits pass through Three ports switch S3 connection RS485-；RS422 conversion circuits by the ports first switch S1 connection TX+, pass through the 4th switch S4 The ports RX+ are connected, and RS422 conversion circuits are directly connected to the ports RX-, and passes through the ports second switch S2 connection TX-；RS232 Conversion circuit by the 5th ports switch S5 connection TXD, pass through the 6th ports switch S6 connection RXD.

The expansion interface with multiprotocol conversion circuit communication is USART interfaces.

The mode switching circuit is also communicated to connect with I/O port.

The beneficial effects of the utility model：The utility model carries out the conversion between each interface by mode setting circuit, The durability of serial communication bus hardware circuit is greatly improved, and can be between RS232, RS485 and RS422 arbitrarily Switching, increase the application range of bus interface, while decreasing the interface quantity of hardware design, reduce hardware design at This, and it has been greatly saved the hardware development time.

Description of the drawings

Fig. 1 is the interface conversion schematic diagram of the utility model.

Fig. 2 is the principles of the present invention block diagram.

Specific implementation mode

The utility model is described in further detail with reference to the accompanying drawings and detailed description.

The utility model provide it is a kind of same interface can be converted, reach same interface is multiplexed it is serial Communication bus interface circuit.

The function of the utility model is realized mainly by multiple and different protocol conversion circuitries and to multiple protocol conversions electricity The mode setting circuit that road switches over realizes the purpose of the interface conversion of the utility model.

The different protocol conversion circuitries of the utility model are existing protocol conversion circuitry, are carried out in the present invention Using.Multiple and different protocol conversion circuitries is communicated with same expansion interface, and carrying out agreement to the interface of needs extension turns Same bus interface is connected after changing, and as the bus interface and external connection after converted, increases the interface of bus interface connection Type.

Conversion between each protocol conversion circuitry realizes that mode setting circuit includes being arranged every by mode setting circuit A protocol conversion circuitry and the on-off switch between the bus interface of external equipment connection on connecting line.The on-off switch can Existing switching device is selected, or other the various switches that can realize the utility model function can also be used.

As shown in Figure 1, the protocol conversion circuitry of the utility model include RS485 conversion circuits, RS422 conversion circuits, RS232 conversion circuits.RS232 conversion circuits by the ports TXD and RXD port communications of mode switching circuit and bus interface, RS422 conversion circuits by the ports TX+ of mode switching circuit and bus interface, the ports TX-, the ports RX+, RX- port communications, RS485 conversion circuits pass through the ports RS485+ of mode switching circuit and bus interface, RS485- port communications.

As shown in Figure 1, to realize that the function of the utility model, RS485 conversion circuits are directly connected to the RS485 of bus interface + port, while RS485 conversion circuits pass through the ports third switch S3 connection RS485-；RS422 conversion circuits pass through first switch The ports S1 connection TX+, by the 4th ports switch S4 connection RX+, and RS422 conversion circuits are directly connected to the ports RX-, and pass through The ports second switch S2 connection TX-；RS232 conversion circuits connect by the 5th ports switch S5 connection TXD, by the 6th switch S6 Connect the ports RXD.

When needing to carry out protocol conversion, the connection of different switching circuit is realized by controlling the opening and closing of each switch.Such as Fig. 1 It is shown, by turning off the switch first switch S1, second switch S2, the 4th switch S4, open third switch S3, the 5th switch S5, The bus interface of 6th switch S6, the utility model are RS422 bus interface, and 1,2,3,4 pins in figure are RS422 buses Interface；When turning off the switch third switch S3, open first switch S1, second switch S2, the 5th switch S5, the utility model it is total Line interface is converted to RS485 bus interface, at this point, 1,2 pins in figure are RS485 bus interface；When open first switch S1, Second switch S2, third switch S3, the 4th switch S4 close the 5th switch S5, the 6th switch S6, then the bus of the utility model Interface conversion is RS232 bus interface, wherein 2,3,5 pins are RS232 bus interface.

Above-mentioned switch as mode setting circuit, can by the wire jumper that is connect with mode setting circuit or toggle switch into Row switch control, achievees the purpose that interface conversion.Due to each same expansion interface of conversion circuit external connection of the utility model, And each conversion circuit externally uses same group of bus interface after mode setting circuit is arranged, and so that bus interface is compatible with a variety of The serial bus communication mode of agreement, and different mode settings corresponds to different serial bus communication modes, greatlys improve The durability of bus interface.

As shown in Fig. 2, the utility model be mainly used in USART interfaces because USART Application of Interface is fairly simple, And USART resources are relatively abundant above various CPU and PCI-USART bridging chips, it can be greatly using USART interfaces Improve the quantity of the scope of application and extension external bus interface of the utility model.

The mode switching circuit of the utility model is also communicated with I/O port, and I/O port connects CPU PCI-USART chips, GPIO mouths of CPU or PCI-USART bridge pieces can be used to be controlled, can also using wire jumper or toggle switch by hardware into Row control, same bus interface can arbitrarily switch between different communication modes.

The external output bus interface of circuit of the utility model while compatible RS232, RS485 and RS422 bus standard, Adjustment output interface signal and mode setting switch are only needed when changing output bus mode, need not redesign interface circuit. And designed based on the compatible type of the above circuit, bus interface can be arranged as required to as appointing in RS232, RS485 and RS422 What is a kind of, and as the difference of applications can switch at any time.

Above-described is only preferred embodiments of the present invention, it is noted that for those skilled in the art For, under the premise of not departing from the utility model general idea, several changes and improvements can also be made, these should also be considered as The scope of protection of the utility model.

Claims

1. a kind of serial communication bus interface circuit of compatible different agreement, it is characterised in that：Turn including multiple and different agreements Circuit is changed, the plurality of different protocol conversion circuitry is communicated with same expansion interface, and the plurality of different agreement turns It changes circuit and same bus interface is connected by mode setting circuit；

The mode setting circuit includes the break-make being arranged on the connecting line of each protocol conversion circuitry and same bus interface Switch.

2. a kind of serial communication bus interface circuit of compatible different agreement according to claim 1, it is characterised in that：Institute State mode setting circuit tie jumper or toggle switch.

3. a kind of serial communication bus interface circuit of compatible different agreement according to claim 1, it is characterised in that：Institute It includes RS485 conversion circuits, RS422 conversion circuits, RS232 conversion circuits to state protocol conversion circuitry.

4. a kind of serial communication bus interface circuit of compatible different agreement according to claim 3, it is characterised in that：Institute State TXD port and RXD port communication of the RS232 conversion circuits by mode switching circuit and bus interface, the RS422 conversions Circuit passes through the ports TX+ of mode switching circuit and bus interface, the ports TX-, the ports RX+, RX- port communications, the RS485 Conversion circuit passes through the ports RS485+ of mode switching circuit and bus interface, RS485- port communications.

5. a kind of serial communication bus interface circuit of compatible different agreement according to claim 4, it is characterised in that：Institute The ports RS485+ that RS485 conversion circuits are directly connected to bus interface are stated, while RS485 conversion circuits are switched by third（S3） Connect the ports RS485-；RS422 conversion circuits pass through first switch（S1）Connect the ports TX+, by the 4th switch（S4）Connection The ports RX+, and RS422 conversion circuits are directly connected to the ports RX-, and pass through second switch（S2）Connect the ports TX-；RS232 turns It changes circuit and passes through the 5th switch（S5）Connect the ports TXD, by the 6th switch（S6）Connect the ports RXD.

6. a kind of serial communication bus interface circuit of compatible different agreement according to claim 1, it is characterised in that：Institute It is USART interfaces to state with the expansion interface of multiprotocol conversion circuit communication.

7. a kind of serial communication bus interface circuit of compatible different agreement according to claim 4, it is characterised in that：Institute Mode switching circuit is stated also to communicate to connect with I/O port.