CN205142203U - Automatic transceiver circuits of RS485 - Google Patents
Automatic transceiver circuits of RS485 Download PDFInfo
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- CN205142203U CN205142203U CN201520941142.8U CN201520941142U CN205142203U CN 205142203 U CN205142203 U CN 205142203U CN 201520941142 U CN201520941142 U CN 201520941142U CN 205142203 U CN205142203 U CN 205142203U
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Abstract
The utility model relates to an automatic transceiver circuits of RS485, it includes the RS485 circuit, the RS485 circuit includes RS485 chip U1, RS485 chip U1's differential signal A end is connected with resistance R5's one end and resistance R3's one end, and RS485 chip U1's differential signal B holds and is connected with resistance R3's the other end and resistance R4's one end, resistance R4's other end ground connection, and resistance R5's the other end and power VCC are connected, and RS485 chip U1's VCC holds and is connected with power VCC, RS485 chip U1's GND termination ground, RS485 chip U1's data receive make can (img file='DDA0000854933710000011. TIF'wi='73'he='58' /) end, data transmission make can the DE end all with can be connected the direction changing reverse circuit connection of messenger ability control signal of input to TXD with the loading, and RS485 chip U1's data transmission DI holds and is connected with the interior earthing terminal of reverse circuit. The utility model discloses compact structure can effectively save outside MCU's control port, and it is long -pending to save the circuit face, saves communication circuit's software resource and development time, and accommodation is wide, safe and reliable.
Description
Technical field
The utility model relates to a kind of circuit, and especially a kind of RS485 automatic transceiving circuit, belongs to the technical field of RS485 circuit.
Background technology
RS-485 is a kind of serial communication protocol based on differential signal transmission, and it has the feature of long-distance transmissions, applies more serial communication protocol when being remote serial communication on industrial equipment.Because it belongs to half-duplex communications protocols, so the conversion receiving and send state need be carried out during communication.Under normal circumstances, RS-485 chip is in accepting state, when needs send data, is transformed into transmission state, after waiting pending data to be sent, then is transformed into accepting state by outside MCU control RS-485 chip by the MCU control RS-485 chip of outside.Judge whether data are sent, normally inquire about the state of UART particular register, or after guaranteeing that data are sent by software delay a period of time, then be transformed into accepting state.In summary, during existing RS485 communication, need the control port taking outside MCU, cause circuit structure complicated, also need the state of inquiring about UART register to judge the transmission state of data, increase the development time.
Summary of the invention
The purpose of this utility model overcomes the deficiencies in the prior art, provides a kind of RS485 automatic transceiving circuit, its compact conformation, effectively can save the control port of outside MCU, save board area, save software resource and the development time of telecommunication circuit, wide accommodation, safe and reliable.
According to the technical scheme that the utility model provides, described RS485 automatic transceiving circuit, comprise the RS485 circuit for realizing differential signal transmission, described RS485 circuit comprises RS485 chip U1; It is characterized in that: the differential signal A end of described RS485 chip U1 is connected with one end of resistance R5 and one end of resistance R3, the differential signal B end of RS485 chip U1 is connected with the other end of resistance R3 and one end of resistance R4, the other end ground connection of resistance R4, the other end of resistance R5 is connected with power supply VCC, the VCC end of RS485 chip U1 is connected with power supply VCC, and the GND of RS485 chip U1 holds ground connection;
The data receiver of RS485 chip U1 is enable
end, data send enable DE hold all with can connect being loaded into the negater circuit that enable control signal that TXD is connected input reverses, and the data of RS485 chip U1 transmission DI holds and is connected with the earth terminal in negater circuit.
Described negater circuit comprises triode Q1, the base terminal of described triode Q1 is connected with one end of resistance R1, the other end of resistance R1 forms TXD and connects input, ground connection after the emitter terminal of triode Q1 is connected with the data sending terminal of RS485 chip U1, the collector terminal of triode Q1 and the data receiver of RS485 chip U1 enable
one end that end, data send enable DE end and resistance R2 connects, and the other end of resistance R2 is connected with power supply VCC.
Advantage of the present utility model: RS485 circuit is connected with negater circuit, hold be connected with outside MCU by the TXD connection input of negater circuit, the data receiver RO of RS485 chip U1, inputing or outputing of differential signal can be realized by differential signal transmission A end, differential signal transmission B end, the enable control signal being loaded into TXD connection input can be carried out level conversion by negater circuit, realize the control of RS485 chip U1 operating state conversion, realize the object of RS485 data communication; Owing to only needing, data receiver RO holds, TXD connects input and is connected with outside MCU, the control port of MCU can be saved, outside MUCU can determine that in RS485 communication process, data send or data receiving state fast, save software resource and development time, circuit structure is simple, reduce board area, safe and reliable.
Accompanying drawing explanation
Fig. 1 is circuit theory diagrams of the present utility model.
Description of reference numerals: 1-negater circuit and 2-RS485 circuit.
Embodiment
Below in conjunction with concrete drawings and Examples, the utility model is described in further detail.
As shown in Figure 1: in order to the control port of outside MCU effectively can be saved, save board area, save software resource and the development time of telecommunication circuit, the utility model comprises the RS485 circuit 2 for realizing differential signal transmission, and described RS485 circuit 2 comprises RS485 chip U1; The differential signal A end of described RS485 chip U1 is connected with one end of resistance R5 and one end of resistance R3, the differential signal B end of RS485 chip U1 is connected with the other end of resistance R3 and one end of resistance R4, the other end ground connection of resistance R4, the other end of resistance R5 is connected with power supply VCC, the VCC end of RS485 chip U1 is connected with power supply VCC, and the GND of RS485 chip U1 holds ground connection;
The data receiver of RS485 chip U1 is enable
end, data send enable DE hold all with can connect being loaded into the negater circuit 1 that enable control signal that TXD is connected input reverses, and the data of RS485 chip U1 transmission DI holds and is connected with the earth terminal in negater circuit 1.
Particularly, RS485 chip U1 can select existing conventional chip model, specifically can select as required, and concrete selection course, known by the art personnel, repeats no more herein.One end that resistance R3 is connected with resistance R5 forms differential signal transmission A and holds, one end that resistance R3 is connected with resistance R4 forms differential signal transmission B and holds, and the differential bus formed by differential signal transmission A end, differential signal transmission B end can realize inputing or outputing of required differential signal.The data receiver RO of RS485 chip U1 holds and is connected with outside MCU, when outside MCU is in data receiving state, RS485 chip U1 passes through differential signal transmission A end, the differential signal of outside receives by differential signal transmission B end, and is held the differential signal transmission of reception to outside MCU by data receiver RO.
The TXD of negater circuit 1 connects input and is used for being connected with the MCU of outside, outside MCU connects the state enable control of input realization to RS485 chip U1 by TXD, by negater circuit 1 by be loaded into enable control signal that TXD connects input oppositely after, can realize the data transmission of outside MCU by the RS485 needed for differential signal transmission A end, the realization of differential signal transmission B end.
Further, described negater circuit 1 comprises triode Q1, the base terminal of described triode Q1 is connected with one end of resistance R1, the other end of resistance R1 forms TXD and connects input, ground connection after the emitter terminal of triode Q1 is connected with the data sending terminal of RS485 chip U1, the collector terminal of triode Q1 and the data receiver of RS485 chip U1 enable
one end that end, data send enable DE end and resistance R2 connects, and the other end of resistance R2 is connected with power supply VCC.
In the utility model embodiment, triode Q1 can adopt NPN triode, and certainly, triode Q1 also can adopt conventional metal-oxide-semiconductor or the switching tube of other types.The magnitude of voltage of power supply VCC can adopt conventional voltage, as 3.3V or 5V, specifically can carry out selection as required and determine.
When not sending data or being in data receiving state, the enable control signal that outside MCU is loaded into TXD connection input is high level, be carried in the triode Q1 conducting that enable control signal that TXD connects input end high level makes in negater circuit 1, after triode Q1 conducting, the data receiver of RS485 chip U1 can be made enable
end, data send enable DE end and are low level, and the data receiver of RS485 chip U1 can be made enable
effectively, RS485 circuit 2 is in data receiving state to end, and differential signal holds input by differential signal transmission A end, differential signal transmission B, and by transferring to outside MCU after the differential signal conversion of the enable RO termination receipts of the data receiver of RS485 chip U1.
When outside MCU needs to send data, and data to be sent are when being high level, then outside MUC is loaded into the enable control signal of TXD connection input is high level, the enable control signal that TXD connects input high level makes triode Q1 conducting, i.e. output low level after negater circuit 1, can make the data receiver of RS485 chip U1 enable
end, data send enable DE end and are low level, and now, the data of RS485 chip U1 send enable DE end and are in enable disarmed state, and RS485 chip U1 is still in transmission state, and now, RS485 chip U1 is in illegal state; The differential bus formed is held to be in high-impedance state by differential signal transmission A end, differential signal transmission B, now produce high level by the pull-up resistor in bus, namely can transmit high level by differential signal transmission A end, differential signal transmission B end, namely reach the object that MCU exports high level.
When outside MCU needs to send data, and when transmission data are low level, the enable control signal being namely loaded into TXD connection input is low level; When the enable control signal of TXD link is low level, then triode Q1 is in off state, under the effect of power supply VCC and resistance R2, makes the data receiver being loaded into RS485 chip U1 enable
end, data send enable DE end and are high level, now, the data of RS485 chip U1 send enable DE end and are in enable effective status, due to the data sending terminal ground connection of RS485 chip U1, then differential signal transmission A end, differential signal transmission B end energy output low level, namely reach the object of MCU output low level.
The utility model RS485 circuit 2 is connected with negater circuit 1, hold be connected with outside MCU by the TXD connection input of negater circuit 1, the data receiver RO of RS485 chip U1, inputing or outputing of differential signal can be realized by differential signal transmission A end, differential signal transmission B end, the enable control signal being loaded into TXD connection input can be carried out level conversion by negater circuit 1, realize the control of RS485 chip U1 operating state conversion, realize the object of RS485 data communication; Owing to only needing, data receiver RO holds, TXD connects input and is connected with outside MCU, the control port of MCU can be saved, outside MUCU can determine that in RS485 communication process, data send or data receiving state fast, save software resource and development time, circuit structure is simple, reduce board area, safe and reliable.
Claims (2)
1. a RS485 automatic transceiving circuit, comprise the RS485 circuit (2) for realizing differential signal transmission, described RS485 circuit (2) comprises RS485 chip U1; It is characterized in that: the differential signal A end of described RS485 chip U1 is connected with one end of resistance R5 and one end of resistance R3, the differential signal B end of RS485 chip U1 is connected with the other end of resistance R3 and one end of resistance R4, the other end ground connection of resistance R4, the other end of resistance R5 is connected with power supply VCC, the VCC end of RS485 chip U1 is connected with power supply VCC, and the GND of RS485 chip U1 holds ground connection;
The data receiver of RS485 chip U1 is enable
end, data send enable DE hold all with can connect being loaded into the negater circuit (1) that enable control signal that TXD is connected input reverses, and the data of RS485 chip U1 transmission DI holds and is connected with the earth terminal in negater circuit (1).
2. RS485 automatic transceiving circuit according to claim 1, it is characterized in that: described negater circuit (1) comprises triode Q1, the base terminal of described triode Q1 is connected with one end of resistance R1, the other end of resistance R1 forms TXD and connects input, ground connection after the emitter terminal of triode Q1 is connected with the data sending terminal of RS485 chip U1, the collector terminal of triode Q1 and the data receiver of RS485 chip U1 enable
one end that end, data send enable DE end and resistance R2 connects, and the other end of resistance R2 is connected with power supply VCC.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520941142.8U CN205142203U (en) | 2015-11-23 | 2015-11-23 | Automatic transceiver circuits of RS485 |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201520941142.8U CN205142203U (en) | 2015-11-23 | 2015-11-23 | Automatic transceiver circuits of RS485 |
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| Publication Number | Publication Date |
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| CN205142203U true CN205142203U (en) | 2016-04-06 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN201520941142.8U Active CN205142203U (en) | 2015-11-23 | 2015-11-23 | Automatic transceiver circuits of RS485 |
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107659476A (en) * | 2017-10-09 | 2018-02-02 | 珠海格力电器股份有限公司 | A kind of telecommunication circuit |
| CN109302204A (en) * | 2018-12-03 | 2019-02-01 | 中国船舶重工集团公司第七0四研究所 | Adaptive transmitting-receiving RS485 circuit |
| CN112712684A (en) * | 2020-12-16 | 2021-04-27 | 安徽阿瑞特汽车电子科技有限公司 | Portable bluetooth 485 conversion boxes for automobile debugging |
| CN112838972A (en) * | 2020-12-31 | 2021-05-25 | 广州航天海特系统工程有限公司 | Enabling control method, device and equipment based on RS-485 transceiver and storage medium |
| CN113411241A (en) * | 2021-05-07 | 2021-09-17 | 宁波奥克斯电气股份有限公司 | RS485 communication circuit, communication system and air conditioning system |
-
2015
- 2015-11-23 CN CN201520941142.8U patent/CN205142203U/en active Active
Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN107659476A (en) * | 2017-10-09 | 2018-02-02 | 珠海格力电器股份有限公司 | A kind of telecommunication circuit |
| CN107659476B (en) * | 2017-10-09 | 2023-03-24 | 珠海格力电器股份有限公司 | Communication device |
| CN109302204A (en) * | 2018-12-03 | 2019-02-01 | 中国船舶重工集团公司第七0四研究所 | Adaptive transmitting-receiving RS485 circuit |
| CN112712684A (en) * | 2020-12-16 | 2021-04-27 | 安徽阿瑞特汽车电子科技有限公司 | Portable bluetooth 485 conversion boxes for automobile debugging |
| CN112838972A (en) * | 2020-12-31 | 2021-05-25 | 广州航天海特系统工程有限公司 | Enabling control method, device and equipment based on RS-485 transceiver and storage medium |
| CN112838972B (en) * | 2020-12-31 | 2022-05-27 | 广州航天海特系统工程有限公司 | Enabling control method, device and equipment based on RS-485 transceiver and storage medium |
| CN113411241A (en) * | 2021-05-07 | 2021-09-17 | 宁波奥克斯电气股份有限公司 | RS485 communication circuit, communication system and air conditioning system |
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