CN201557127U - RS485 half-duplex transmit-receive automatic switch circuit - Google Patents
RS485 half-duplex transmit-receive automatic switch circuit Download PDFInfo
- Publication number
- CN201557127U CN201557127U CN2009202797234U CN200920279723U CN201557127U CN 201557127 U CN201557127 U CN 201557127U CN 2009202797234 U CN2009202797234 U CN 2009202797234U CN 200920279723 U CN200920279723 U CN 200920279723U CN 201557127 U CN201557127 U CN 201557127U
- Authority
- CN
- China
- Prior art keywords
- communication chip
- resistance
- resistor
- pin
- data
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
Images
Landscapes
- Dc Digital Transmission (AREA)
Abstract
The utility model provides a RS485 half-duplex transmit-receive automatic switch circuit which comprises a micro processor, a RS485 communication chip and a RS485 bus. A data receiving pin of the micro processor is connected with an output end of a receiver of the RS485 communication chip; a data transmitting pin of the micro processor is connected with a base electrode of a triode through a limiting resistor; a collector electrode of the triode is connected with an output end of the receiver and an output end of the transmitter of the RS485 communication chip and is connected with a power supply through a third resistor; an emitter electrode of the triode is grounded; the input end of the transmitter of the RS485 communication chip is grounded; an A pin of the RS485 communication chip is connected with the power supply through a pull-up resistor; and a B pin of the RS485 communication chip is grounded through a pull-down resistor. The RS485 half-duplex transmit-receive automatic switch circuit of the utility model can automatically transmit and receive the working state.
Description
Technical field
The utility model relates to the communication interface technique field, particularly a kind of RS485 half-duplex automatic receiving-transmitting switching circuit.
Background technology
Half-duplex (Half Duplex) transfer of data index still can not transmit simultaneously according to transmitting on the both direction of a signal vehicle.Specifically be meant any time at communication process, information both can pass to N by M, can pass to M by N again, but can only be existed by the transmission on the direction simultaneously.When adopting half-duplex mode, the transmitter of each end of communication system and receiver are transferred on the order wire by receiving/send out switch, and therefore the switching of travel direction, can postpone by generation time.
The RS485 standard is the half-duplex operation agreement.RS485 is applicable to that the shared a pair of circuit of receiving-transmitting sides communicates, and be applicable to that also sharing a pair of circuit between a plurality of points carries out the bus mode networking, but communication can only be semiduplex.
Introduce the operation principle of RS485 in the prior art below in conjunction with accompanying drawing.
Referring to Fig. 1, this figure is the fundamental diagram of RS485 transceive data in the prior art.
At first introduce the definition of 8 pins of RS485 communication chip.
RO is the receiver output of RS485;
DI is the transmitter input of RS485;
/ RE is a receiver output enable end, and low level is effective;
DE is a transmitter output enable end, and high level is effective;
A and B be two differential data transmission lines of corresponding RS485 communication bus respectively;
VCC and GND are respectively power supply and ground.
RS485 is by the data on A and the B reception bus, process RS485 communication chip with the level conversion of data is and microprocessor (MCU, Microcontroller Unit) Pi Pei transistor-transistor logic level (TTL, Transistor-Transistor logic) after, is sent to the reception pin RXD of MCU through the RO pin.
The data of MCU are through sending the DI that pin TXD is sent to RS485, and RS485 sends on the bus through A and B after data are converted to the level that mates with bus data.
Because the operating characteristic of RS485 is exactly half-duplex operation, so the operating state of RS485 is transmission or receives that need the level of control/RE and DE to realize, pin R/D connection/RE and DE are controlled in the read-write of MCU.When R/D was high level, the RS485 communication chip was in transmit status; When R/D was low level, the RS485 communication chip was in accepting state.The transmit status of RS485 communication chip and accepting state are to be benchmark with this MCU and this RS485 communication chip place node herein, describe the state of RS485 communication chip.The RS485 communication chip is in transmit status, is meant that RS485 sends to the data of MCU on the bus.The RS485 communication chip is in accepting state, is meant that RS485 receives data from bus, again the data that receive is sent to MCU.
Therefore, when switching the operating state of RS485 communication chip, all need to change the level of the control pin R/D of MCU at every turn, can cause the transmitting-receiving of whole data slower like this, cause time delay.
The utility model content
The technical problems to be solved in the utility model provides a kind of RS485 half-duplex automatic receiving-transmitting switching circuit, the reception of the RS485 communication chip that can automatically switch and transmission operating state.
The utility model embodiment provides a kind of RS485 half-duplex automatic receiving-transmitting switching circuit, comprises microprocessor, RS485 communication chip and RS485 bus; It is characterized in that the Data Receiving pin of described microprocessor connects the receiver output of RS485 communication chip; The data transmitting pin of described microprocessor connects the base stage of triode by current-limiting resistance;
The transmitter input end grounding of described RS485 communication chip;
The collector electrode of described triode connects the receiver output enable end and the transmitter output enable end of RS485 communication chip, connects power supply by the 3rd resistance simultaneously; The grounded emitter of described triode;
The A pin of described RS485 communication chip connects power supply by pull-up resistor;
The B pin of described RS485 communication chip is by pull down resistor ground connection.Preferably, the resistance of the resistance of described pull-up resistor and described pull down resistor is identical.
Preferably, the resistance of the resistance of described pull-up resistor and described pull down resistor is identical all is 1000 ohm.
Preferably, the resistance of the resistance of described pull-up resistor and described pull down resistor is identical all is 2000 ohm.
The utility model embodiment should provide a kind of RS485 half-duplex automatic receiving-transmitting switching circuit, comprised microprocessor, RS485 communication chip and RS485 bus; The Data Receiving pin of described microprocessor connects the receiver output of RS485 communication chip; The data transmitting pin of described microprocessor connects the base stage of triode by current-limiting resistance;
The collector electrode of described triode connects the receiver output enable end and the transmitter output enable end of RS485 communication chip, connects power supply by the 3rd resistance simultaneously;
The grounded emitter of described triode;
The transmitter input of described RS485 communication chip connects the data transmitting pin of described microprocessor;
The A pin of described RS485 communication chip connects power supply by pull-up resistor;
The B pin of described RS485 communication chip is by pull down resistor ground connection.
Preferably, the resistance of the resistance of described pull-up resistor and described pull down resistor is identical.
Preferably, the resistance of the resistance of described pull-up resistor and described pull down resistor is identical all is 1000 ohm.
Preferably, the resistance of the resistance of described pull-up resistor and described pull down resistor is identical all is 2000 ohm.
Compared with prior art, the utlity model has following advantage:
The RS485 half-duplex automatic receiving-transmitting switching circuit that the utility model embodiment provides, the TXD pin of MCU is passed through triode Q1 control/RE and DE, utilize MCU when sending data with " 0 " as start bit, send after the data with " 1 " as stop bits, realize the automatic switchover of the operating state of RS485.When MCU sent data, the stop bits that TXD sends was " 1 ", therefore, and the triode conducting, at this moment/RE and DE are low level, and RO is effective, and the operating state of RS485 is automatically converted to reception by transmission.When MCU began to send data, the start bit that TXD sends was " 0 ", and therefore, triode ends, at this moment/RE and DE are high level, and DI is effective, and RS485 is in the transmission operating state.Because this moment, DI was in low level, therefore, RS485 can send to " 0 " on the bus.When the TXD of MCU sends " 1 ", the triode conducting, at this moment/RE and DE are low level, RS485 is in the reception operating state, but, this moment, bus was in idle condition, because the effect of pull-up resistor R1 and pull down resistor R2 makes the data on the bus be " 1 ", thereby guaranteed that bus can obtain correct data " 1 ".And then other nodes also can obtain data " 1 " from bus.The RS485 half-duplex automatic receiving-transmitting switching circuit that two embodiment of the utility model provide does not need to control separately the level of the R/D of MCU, switches the operating state of RS485 communication chip.When the RS485 communication chip is in transmit status, control by the turn-on and turn-off of triode Q1.When the RS485 communication chip is in accepting state, thereby can guarantee correctly to receive data by TXD output high level.
Description of drawings
Fig. 1 is the fundamental diagram of RS485 transceive data in the prior art;
Fig. 2 is the utility model RS485 half-duplex automatic receiving-transmitting switching circuit first example structure figure;
Fig. 3 is the utility model RS485 half-duplex automatic receiving-transmitting switching circuit second example structure figure.
Embodiment
For those skilled in the art understand better and implement the utility model, at first RS485 is simply introduced.
In the automated communication field,, press for a kind of bus and can be fit to remote digital communication along with the development of dcs.On the basis of RS-422 standard, Electronic Industries Association (EIA, ElectronicIndustries Association) has worked out a kind of support multinode, remote and receive highly sensitive RS485 bus standard.
The RS485 bus standard adopts balanced type to send, and the data collector that differential type receives drives bus, concrete specification requirement:
1) input resistance of receiver RIN 〉=12k Ω;
2) driver can be exported ± common-mode voltage of 7V;
3) electric capacity≤50pF of input;
4) be 32 at the node number, disposed under the situation of terminal resistance of 120 Ω that driver at least can also output voltage 1.5V (size of terminal resistance and the relating to parameters of used twisted-pair feeder);
5) input sensitivity of receiver is that (promptly (V+)-(V-) 〉=0.2V represents signal " 1 " to 200mV; (V+)-(V-)≤-0.2V, expression signal " 0 "); V+ herein and V-refer to A on the RS485 and the voltage on the B;
Because remote, the multinode (32) of RS485 and the low characteristic of transmission line cost make the RS485 of EIA become the first-selected standard of transfer of data in the commercial Application.
For above-mentioned purpose of the present utility model, feature and advantage can be become apparent more, embodiment of the present utility model is described in detail below in conjunction with accompanying drawing.
Embodiment one:
Referring to Fig. 2, this figure is the utility model RS485 half-duplex automatic receiving-transmitting switching circuit first example structure figure.
The TXD of MCU connects the RS485 communication chip through triode Q1 again by current-limiting resistance R4 in the present embodiment.
The TXD of MCU connects the base stage of triode Q1 by current-limiting resistance R4.
The grounded emitter of triode Q1; The collector electrode of triode connects RS485 communication chip/RE pin and DE pin, and collector electrode connects power supply VCC by the 3rd resistance R 3 simultaneously.
The DI pin ground connection of RS485 communication chip; RO connects the RXD pin of MCU; The A pin connects VCC by first resistance R 1; The B pin connects ground by second resistance R 2.The differential data line of while A pin and B pin connecting bus.
The following describes the operation principle of this embodiment.
Receiving data with the RS485 communication chip to bus introduces with the transmission data.
First: the RS485 communication chip receives the data of bus.
The TXD pin of MCU is exported high level when idle condition, triode Q1 conducting this moment, the RS485 communication chip /RE and DE are low level, therefore, the RS485 communication chip is in accepting state.So TXD pin RS485 communication chip when idle condition can correctly receive the data on the bus.And then will become the RXD pin that is sent to MCU behind the Transistor-Transistor Logic level by the RO pin from the data transaction that bus receives.
Second: the RS485 communication chip sends data to bus.
RS485 communication chip herein sends data to bus and is meant that MCU passes through the RS485 communication chip and sends data to bus.
Need to prove that the standard agreement that MCU sends data is: the start bit of data is " 0 ", and the stop bits of data is " 1 ".For example, start bit is 1bit, and the data of transmission are 8bit, and stop bits is 1bit, sends the data of 10bit altogether.
When MCU began to send data, the start bit that TXD sends was " 0 ", and therefore, triode Q1 ends, at this moment/RE and DE are high level, and DI is effective, and RS485 is in the transmission operating state.Because DI ground connection, therefore, RS485 can send to " 0 " on the bus.
When the TXD of MCU sends " 1 ", triode Q1 conducting, at this moment/RE and DE are low level, RS485 is in the reception operating state, but, this moment, bus was in idle condition, because the effect of pull-up resistor R1 and pull down resistor R2 makes the data on the bus be " 1 ", thereby guaranteed that bus can obtain correct data " 1 ".And then other nodes also can obtain data " 1 " from bus.
Need to prove, when bus is in idle condition,, make two data wire states be in logical one owing to pull-up resistor R1 on two data wires and the effect of pull down resistor R2.
Need to prove, the resistance of pull-up resistor R1 and pull down resistor R2 can be different, also can be identical, as long as can guarantee that bus is when idle condition, the magnitude of voltage that magnitude of voltage on the A line deducts on the B line gets final product more than or equal to 200mV, and the difference that two data wires embody on the bus is a logical one like this.
Need to prove that pull-up resistor R1 and pull down resistor R2 make beyond the level that produces logical one on the bus when guaranteeing that bus is in idle condition; When bus was in running order, pull-up resistor R1 and pull down resistor R2 can also make the signal on the bus more stable, avoided signal to produce bigger fluctuation.
When MCU sent data, the stop bits that TXD sends was " 1 ", therefore, and the triode conducting, at this moment/RE and DE are low level, and RO is effective, and the operating state of RS485 is automatically converted to reception by transmission.
The RS485 half-duplex automatic receiving-transmitting switching circuit that the utility model embodiment provides utilize MCU when sending data with " 0 " as start bit, send after the data with " 1 " as stop bits, and triode and pull-up resistor and pull down resistor are realized the automatic switchover of the operating state of RS485.This circuit is realized simple and convenient, can realize the reception of RS485 communication chip and the switching of transmit status automatically, thereby the R/D end that saves MCU has been avoided time delay to sending and receiving the control that enables.Thereby the data that improve whole system send and inbound pacing.
Embodiment two:
Referring to Fig. 3, this figure is the utility model RS485 half-duplex automatic receiving-transmitting switching circuit second example structure figure.
The TXD of MCU connects the RS485 communication chip through triode Q1 again by current-limiting resistance R4 in the present embodiment.
The TXD of MCU connects the base stage of triode Q1 again by current-limiting resistance R4.
The grounded emitter of triode Q1; The collector electrode of triode connects RS485 communication chip/RE pin and DE pin, and collector electrode connects power supply VCC by the 3rd resistance R 3 simultaneously.
The DI pin of RS485 communication chip connects the TXD of MCU; RO connects the RXD pin of MCU; The A pin connects VCC by first resistance R 1; The B pin connects ground by second resistance R 2.The differential data line of while A pin and B pin connecting bus.
The following describes the operation principle of this embodiment.
Receiving data with the RS485 communication chip to bus introduces with the transmission data.
First: the RS485 communication chip receives the data of bus.This process is identical with embodiment one, does not repeat them here.
Second: the RS485 communication chip sends data to bus.
RS485 communication chip herein sends data to bus and is meant that MCU passes through the RS485 communication chip and sends data to bus.
Need to prove that the standard agreement that MCU sends data is: the start bit of data is " 0 ", and the stop bits of data is " 1 ".For example, start bit is 1bit, and the data of transmission are 8bit, and stop bits is 1bit, sends the data of 10bit altogether.
When MCU began to send data, the start bit that TXD sends was " 0 ", and therefore, triode Q1 ends, at this moment/RE and DE are high level, and DI is effective, and RS485 is in the transmission operating state.Because DI directly connects the TXD of MCU now, therefore, RS485 can send to " 0 " on the bus.
When the TXD of MCU sends " 1 ", triode Q1 conducting, at this moment/RE and DE are low level, RS485 is in the reception operating state, but, this moment, bus was in idle condition, and the effect of pull-up resistor R1 and pull down resistor R2 makes the data on the bus be " 1 ", thereby guarantees that bus can obtain correct data " 1 ".And then other nodes also can obtain data " 1 " from bus, guarantee that the data " 1 " that MCU sends also can correctly be obtained by other nodes.
Need to prove, when bus is in idle condition,, make two data wire states be in logical one owing to pull-up resistor R1 on two data wires and the effect of pull down resistor R2.
Need to prove, the resistance of pull-up resistor R1 and pull down resistor R2 can be different, also can be identical, as long as can guarantee that bus is when idle condition, the magnitude of voltage that magnitude of voltage on the A line deducts on the B line gets final product more than or equal to 200mV, and the state that embodies of bus is a logical one like this.
Need to prove that pull-up resistor R1 and pull down resistor R2 make beyond the state that produces logical one on the bus when guaranteeing that bus is in idle condition; When bus was in running order, pull-up resistor R1 and pull down resistor R2 can also make the signal on the bus more stable, avoided signal to produce bigger fluctuation.
When MCU sent data, the stop bits that TXD sends was " 1 ", therefore, and triode Q1 conducting, at this moment/RE and DE are low level, and RO is effective, and the operating state of RS485 is automatically converted to reception by transmission.
The RS485 half-duplex automatic receiving-transmitting switching circuit that two embodiment of the utility model provide does not need to control separately the level of the R/D of MCU, switches the operating state of RS485 communication chip.But the data that the TXD pin sends when utilizing MCU to send data are directly controlled RS485's/RE and DE.The communication standard that has also utilized RS485 is half-duplex, and when RS485 was in accepting state, bus was in idle condition.
When the RS485 communication chip is in transmit status, control by the turn-on and turn-off of triode Q1.When the RS485 communication chip is in accepting state, thereby can guarantee correctly to receive data by TXD output high level.
The above only is preferred embodiment of the present utility model, is not the utility model is done any pro forma restriction.Though the utility model discloses as above with preferred embodiment, yet be not in order to limit the utility model.Any those of ordinary skill in the art, do not breaking away under the technical solutions of the utility model scope situation, all can utilize the method and the technology contents of above-mentioned announcement that technical solutions of the utility model are made many possible changes and modification, or be revised as the equivalent embodiment of equivalent variations.Therefore, every content that does not break away from technical solutions of the utility model, all still belongs in the scope of technical solutions of the utility model protection any simple modification, equivalent variations and modification that above embodiment did according to technical spirit of the present utility model.
Claims (8)
1. a RS485 half-duplex automatic receiving-transmitting switching circuit comprises microprocessor, RS485 communication chip and RS485 bus; It is characterized in that the Data Receiving pin of described microprocessor connects the receiver output of RS485 communication chip; The data transmitting pin of described microprocessor connects the base stage of triode by current-limiting resistance;
The transmitter input end grounding of described RS485 communication chip;
The collector electrode of described triode connects the receiver output enable end and the transmitter output enable end of RS485 communication chip, connects power supply by the 3rd resistance simultaneously; The grounded emitter of described triode;
The A pin of described RS485 communication chip connects power supply by pull-up resistor;
The B pin of described RS485 communication chip is by pull down resistor ground connection.
2. RS485 half-duplex automatic receiving-transmitting switching circuit according to claim 1 is characterized in that, the resistance of described pull-up resistor is identical with the resistance of described pull down resistor.
3. RS485 half-duplex automatic receiving-transmitting switching circuit according to claim 2 is characterized in that, the resistance of described pull-up resistor is identical with the resistance of described pull down resistor all to be 1000 ohm.
4. RS485 half-duplex automatic receiving-transmitting switching circuit according to claim 2 is characterized in that, the resistance of described pull-up resistor is identical with the resistance of described pull down resistor all to be 2000 ohm.
5. a RS485 half-duplex automatic receiving-transmitting switching circuit comprises microprocessor, RS485 communication chip and RS485 bus; It is characterized in that the Data Receiving pin of described microprocessor connects the receiver output of RS485 communication chip; The data transmitting pin of described microprocessor connects the base stage of triode by current-limiting resistance;
The collector electrode of described triode connects the receiver output enable end and the transmitter output enable end of RS485 communication chip, connects power supply by the 3rd resistance simultaneously;
The grounded emitter of described triode;
The transmitter input of described RS485 communication chip connects the data transmitting pin of described microprocessor;
The A pin of described RS485 communication chip connects power supply by pull-up resistor;
The B pin of described RS485 communication chip is by pull down resistor ground connection.
6. RS485 half-duplex automatic receiving-transmitting switching circuit according to claim 5 is characterized in that, the resistance of described pull-up resistor is identical with the resistance of described pull down resistor.
7. RS485 half-duplex automatic receiving-transmitting switching circuit according to claim 6 is characterized in that, the resistance of described pull-up resistor is identical with the resistance of described pull down resistor all to be 1000 ohm.
8. RS485 half-duplex automatic receiving-transmitting switching circuit according to claim 6 is characterized in that, the resistance of described pull-up resistor is identical with the resistance of described pull down resistor all to be 2000 ohm.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202797234U CN201557127U (en) | 2009-11-19 | 2009-11-19 | RS485 half-duplex transmit-receive automatic switch circuit |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2009202797234U CN201557127U (en) | 2009-11-19 | 2009-11-19 | RS485 half-duplex transmit-receive automatic switch circuit |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN201557127U true CN201557127U (en) | 2010-08-18 |
Family
ID=42616816
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN2009202797234U Expired - Fee Related CN201557127U (en) | 2009-11-19 | 2009-11-19 | RS485 half-duplex transmit-receive automatic switch circuit |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN201557127U (en) |
Cited By (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102681962A (en) * | 2012-04-18 | 2012-09-19 | 华为技术有限公司 | Connecting device and anti-jamming system between node devices |
| CN103441780A (en) * | 2013-08-16 | 2013-12-11 | 北京汉柏科技有限公司 | Communication circuit capable of enabling direction of RS-485 chip to be automatically changed |
| CN104009902A (en) * | 2014-05-15 | 2014-08-27 | 京信通信系统（中国）有限公司 | Automatic transceiving circuit |
| CN107888222A (en) * | 2017-11-16 | 2018-04-06 | 郑州云海信息技术有限公司 | A kind of circuit structure and method of optimization NCSI signal qualitys |
| CN111600696A (en) * | 2020-05-29 | 2020-08-28 | 深圳市优必选科技股份有限公司 | Design circuit and method based on half-duplex communication bus and robot |
| CN113946529A (en) * | 2021-10-15 | 2022-01-18 | 上海商汤阡誓科技有限公司 | Circuit system, signal processing method and device |
-
2009
- 2009-11-19 CN CN2009202797234U patent/CN201557127U/en not_active Expired - Fee Related
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN102681962A (en) * | 2012-04-18 | 2012-09-19 | 华为技术有限公司 | Connecting device and anti-jamming system between node devices |
| CN102681962B (en) * | 2012-04-18 | 2015-06-17 | 华为技术有限公司 | Connecting device and anti-jamming system between node devices |
| CN103441780A (en) * | 2013-08-16 | 2013-12-11 | 北京汉柏科技有限公司 | Communication circuit capable of enabling direction of RS-485 chip to be automatically changed |
| CN104009902A (en) * | 2014-05-15 | 2014-08-27 | 京信通信系统（中国）有限公司 | Automatic transceiving circuit |
| CN107888222A (en) * | 2017-11-16 | 2018-04-06 | 郑州云海信息技术有限公司 | A kind of circuit structure and method of optimization NCSI signal qualitys |
| CN107888222B (en) * | 2017-11-16 | 2020-08-25 | 苏州浪潮智能科技有限公司 | Circuit structure and method for optimizing NCSI signal quality |
| CN111600696A (en) * | 2020-05-29 | 2020-08-28 | 深圳市优必选科技股份有限公司 | Design circuit and method based on half-duplex communication bus and robot |
| CN111600696B (en) * | 2020-05-29 | 2023-04-07 | 深圳市优必选科技股份有限公司 | Design circuit and method based on half-duplex communication bus and robot |
| CN113946529A (en) * | 2021-10-15 | 2022-01-18 | 上海商汤阡誓科技有限公司 | Circuit system, signal processing method and device |
| CN113946529B (en) * | 2021-10-15 | 2024-03-22 | 上海商汤阡誓科技有限公司 | Circuit system, signal processing method and device |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN101719112A (en) | Half-duplex automatic receiving-transmitting switching circuit of RS485 | |
| CN201557127U (en) | RS485 half-duplex transmit-receive automatic switch circuit | |
| CN102914982B (en) | Bus structure for distribution control system of robot | |
| CN100563117C (en) | A kind of power cord chopped wave communication transmitting-receiving circuit | |
| CN204965418U (en) | Novel RS -485 interface drive circuit | |
| CN101594171B (en) | Power cord chopper communication transceiving circuit | |
| CN101470151B (en) | CAN bus isolation circuit | |
| CN109600288B (en) | Isolation circuit and electronic control unit of controller area network CAN signal | |
| CN110301115A (en) | Subscriber station for bus system and the method for the data transmission in bus system | |
| CN101031899A (en) | Device for transmiting signal | |
| CN202014233U (en) | Digital signal communication circuit and air conditioner equipped therewith | |
| CN102169472A (en) | RS485 bus interface circuit | |
| CN210609167U (en) | Communication switching circuit and communication switching device | |
| CN210137320U (en) | RS485 circuit capable of automatically switching receiving and transmitting states | |
| CN210270649U (en) | Control circuit for valve island bus single-line data transmission | |
| CN212811729U (en) | On-board communication circuit and device based on CAN communication | |
| CN209748544U (en) | RS485 half-duplex is from receiving and dispatching circuit | |
| CN201515367U (en) | Power line chopping communication transceiver circuit | |
| CN209046639U (en) | A kind of data transmit-receive circuit and communication instrument | |
| CN106301450A (en) | Repeat circuit and half duplex communication circuit for half duplex communication | |
| CN107809264B (en) | RS485 changes eight way RS 232's wireless communication converter | |
| CN206077379U (en) | Repeat circuit and half duplex communication circuit for half duplex communication | |
| CN103001841B (en) | A kind of automotive bus system | |
| CN101738988B (en) | Communication circuit of programmer for electric vehicle controller | |
| WO2022041000A1 (en) | Can communication-based intra-board communication circuit and apparatus |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| CF01 | Termination of patent right due to non-payment of annual fee |
Granted publication date: 20100818 Termination date: 20141119 |
|
| EXPY | Termination of patent right or utility model |