CN207965868U - One kind loading by force jamproof serial expanded circuit - Google Patents

Abstract

The utility model provides one kind and loading jamproof serial expanded circuit by force, the serial expanded circuit is electrically connected on the port RXD, TXD and I/O of microprocessor, it is characterized in that, it is made of analog switch chip, decoder chip, multiple first level shifting circuits and multiple second electrical level conversion circuits, realizes microprocessor input, the extension of output port；First level shifting circuit realizes conversion of the RS232 level to Transistor-Transistor Logic level；The second electrical level conversion circuit, realize the conversion to RS232 level for Transistor-Transistor Logic level, the serial expanded circuit of the utility model can effectively realize the extension of the ports microprocessor RXD and TXD, TTL and RS232 level conversions are realized using optic coupling element, it not only realizes signal transmitting, but also also improves load capacity, realize Phototube Coupling, and impact resistance, promote the interference free performance of circuit extension.

Description

One kind loading by force jamproof serial expanded circuit

Technical field

The utility model belongs to electroporation field, is related to a kind of expanded circuit, and in particular to one kind loads by force anti-interference Serial expanded circuit.

Background technology

In the total quantity control system of environmental protection, it is often necessary to carry out concentrated collection, analysis to the data of multiple online equipments And presentation, and the data of each enterprise are sent to central management platform in real time and carry out unified presentation, it is held convenient for authorities' observation Method, the data accurate delivery acquired in real time in order to ensure online equipment to central platform, online managing and control system use serial communication Mode replaces analog quantity, avoids AD conversion and accumulated error caused by calculating, in this case, online managing and control system Must have multiple RS232 serial ports, Normal practice is to select industrial personal computer to match dedicated serial port expanding module again to realize at present, due to work Control machine and serial port expanding module are expensive, and the serial ports extended generally uses RS232 chips to carry out level conversion, the anti-external world Impact capacity is weak, such as thundery sky, be easy to cause serial ports damage.

And with the development of embedded system, use the series microprocessors such as A8 for the development platform of core, price is low, Industrial personal computer can be substituted completely in terms of function, and the data for meeting total quantity control system preserve, analysis, the requirements such as are presented, and micro- place Reason device chip serial ports is less, only needs extended serial port that the requirement of data acquisition can be realized.

The current introduction in relation to serial ports expansion, such as be extended using serial port extended chip GM8125, due to such core Piece is expensive and the halt production that has, such method cannot meet actual requirement very well.Have simply using variable connector+ RS232 chips switch over, but with the development of microprocessor, supply voltage is lower and lower, are 3.3V mostly at present, and multichannel The internal resistance of switch is increased with the reduction of supply voltage, causes the signal between microprocessor and RS232 chips to decay serious, Cause to deform, the requirement of normal communication cannot be met；The application in relation to optocoupler in serial ports expansion is also only played at present simultaneously The effect of Phototube Coupling, can not yet realize the function of TTL and RS232 level conversions, also enclose and do not make full use of the anti-dry of optocoupler The effect of disturbing.

Utility model content

The utility model aim is in view of the drawbacks of the prior art and insufficient, provides and a kind of loading jamproof serial ports by force Expanded circuit realizes TTL and RS232 level conversions using optocoupler, not only realizes signal transmitting, but also also improve load Ability realizes Phototube Coupling, and impact resistance promotes the interference free performance of circuit extension.

In order to solve the above technical problems, the embodiments of the present invention, which provide one kind, loading by force jamproof serial ports expansion electricity Road, the serial expanded circuit are electrically connected on the port RXD, TXD and I/O of microprocessor, which is characterized in that are opened by simulation Close chip, decoder chip, be electrically connected multiple data input pins of analog switch chip multiple first level turn It changes circuit and multiple second electrical level conversion circuits composition in multiple output ends of decoder chip is electrically connected, realize micro- Processor input, the extension of output port；

The ports RXD of the output end connection microprocessor of the analog switch chip, the address of the analog switch chip are defeated Enter the ports I/O of end connection microprocessor, the data input pin of the analog switch chip passes through multiple first level conversions respectively Circuit is electrically connected the receiving port RXD of external equipment_i, realize the extension of microprocessor input mouth；

The decoder chip input terminal electrical connection microprocessor the ports TXD and I/O, the decoder chip it is defeated Outlet is electrically connected the emission port TXD for connecting external equipment by multiple second electrical level conversion circuits respectively_i, realize micro- place Manage the extension of device output port；

First level shifting circuit, including the first optocoupler Q1, second optocoupler Q2, R1 and R3 realize that RS232 level arrives The conversion of Transistor-Transistor Logic level；

The second electrical level conversion circuit, including third optocoupler Q3, the 4th optocoupler Q4, phase inverter, R6, R8 and R10 are realized For Transistor-Transistor Logic level to the conversion of RS232 level.

Further, the analog switch chip is HCF4051 chips, and the decoder chip is 74HC138 chips, real Existing 8 Bits Expandings.

Further, input port X0 ~ X7 of the HCF4051 chips is separately connected 8 the first level shifting circuits of tunnel；Institute Port INH, GND and the VEE for stating HCF4051 chips are grounded；The port VCC of the HCF4051 chips meets power supply VCC；It is described Address choice port A, B, C of HCF4051 chips are all connected with the ends I/O of microprocessor, realize the selection of eight tunnels input；It is described The port x of HCF4051 chips connects the ports RXD of microprocessor, realizes and corresponds to input according to the signal behavior of address selection port The signal at end is sent to the ports RXD.Further, output port Y0 ~ Y7 of three or the eight decoder 74HC138 is separately connected eight Road second electrical level conversion circuit；Address choice port A, B, C of three or the eight decoder 74HC138 is all connected with the IO of microprocessor The selection of eight tunnels output is realized at end；Port G1, VCC of three or the eight decoder 74HC138 meets power supply VCC；Three or eight decoding Port G2B and the VSS ground connection of device 74HC138, the port G2A of three or the eight decoder 74HC138 connect the ends TXD of microprocessor Mouthful, it realizes and output end transmission data is corresponded to according to the signal behavior of address selection port.

Further, first optocoupler, the second optocoupler, third optocoupler and the 4th optocoupler select TLP785, described TLP785 includes pin 1, pin 2, pin 3 and pin 4, which is respectively anode, cathode, emission port and current collection end Mouthful.

Further, the pin 2 of the pin 1 of first optocoupler and the second optocoupler is grounded；The pin 2 of first optocoupler Pass through the receiving port RXD of R3 connection external equipments_i；The pin 3 of first optocoupler and the pin 4 of the second optocoupler are connected in parallel Any input port X in X0 ~ X7 of HCF4051_i；The pin 4 of first optocoupler by pull-up resistor R1 connection power supply VCC, The pin 3 of second optocoupler is grounded；Wherein, R1 is 100 Ω, and R3 is 2 k Ω.

Further, the pin 1 of the third optocoupler is connected by pull-up resistor R6 connection power supply VCC, pin 2 Either output port Y in Y0 ~ Y7 of 74HC138_i, the emission port TXD of the connection external equipment of pin 3_i, 4 connection+12V of pin is straight Galvanic electricity；The pin 1 of 4th optocoupler passes through phase inverter and third optocoupler by pull-up resistor R8 connection power supply VCC, pin 2 Pin 2 is connected in parallel 74HC138 output ports Y_i, pin 3 passes through resistance R10 connections -12V DC electricity, pin 4 and third optocoupler Pin 3 be connected in the emission port TXD of external equipment in parallel_i；Wherein, R6 is 1k Ω, and R8 is that 2 k Ω, R10 are 100 Ω, institute It states phase inverter and selects 74HC04.

The above-mentioned technical proposal of the utility model has the beneficial effect that：

(1) the utility model not only realizes the expansion of 1 expansion 8 using three or eight decoder 74HC138 as extension gating is sent The level shifting circuit opened up function, while optocoupler being coordinated to realize, realizes the isolation of signal so that the load of microprocessor institute band Mitigate significantly, to improve the load capacity of microprocessor, for receiving extension using MOS type chip HCF4051 as simulation Switch, realizes the extension of eight tunnels, realizes signal isolation by using optocoupler level shifting circuit, while by the high level of photoelectric coupled circuit Directly driven by 100 Ω resistance by power supply VCC, and low level is grounded by optocoupler, effectively solves HCF4051 analog switches Internal resistance influences, and further promotes load capacity.

(2) serial expanded circuit of the utility model can effectively realize the extension of the ports microprocessor RXD and TXD, profit TTL and RS232 level conversions are realized with optic coupling element, not only realize signal transmitting, but also also improve load capacity, it is real Existing Phototube Coupling, and impact resistance, promote the interference free performance of circuit extension.

Description of the drawings

In order to illustrate the embodiment of the utility model or the technical proposal in the existing technology more clearly, below will be to embodiment Or attached drawing needed to be used in the description of the prior art is briefly described, it should be apparent that, the accompanying drawings in the following description is only It is some embodiments of the utility model, for those of ordinary skill in the art, before not making the creative labor property It puts, other drawings may also be obtained based on these drawings.

Fig. 1 is the extension principle general diagram of the utility model；

Fig. 2 is the circuit diagram of the serial expanded circuit of the utility model.

Specific implementation mode

In order to make the technical problems, technical solutions and advantages to be solved by the utility model clearer, below in conjunction with attached drawing And specific embodiment is described in detail.

Referring to Fig. 1 and Fig. 2, a kind of to load jamproof serial expanded circuit by force, the serial expanded circuit is electrically connected On the port RXD, TXD and I/O of microprocessor, by analog switch chip, decoder chip, it is electrically connected and is opened in simulation It closes multiple first level shifting circuits of multiple data input pins of chip and is electrically connected in the multiple of decoder chip Multiple second electrical level conversion circuits of output end form, and realize microprocessor input, the extension of output port.

The ports RXD of the output end connection microprocessor of the analog switch chip, the address of the analog switch chip are defeated Enter the ports I/O of end connection microprocessor, the data input pin of the analog switch chip passes through multiple first level conversions respectively Circuit is electrically connected the receiving port RXD of external equipment_i, realize the extension of microprocessor input mouth；The decoder chip Input terminal is electrically connected the ports TXD and I/O of microprocessor, and the output end of the decoder chip passes through multiple second electrical levels respectively Conversion circuit is electrically connected the emission port TXD for connecting external equipment_i, realize the extension of output end of microprocessor mouth.It is described First level shifting circuit, including the first optocoupler Q1, second optocoupler Q2, R1 and R3 realize that RS232 level turns to Transistor-Transistor Logic level It changes；The second electrical level conversion circuit, including third optocoupler Q3, the 4th optocoupler Q4, phase inverter, R6, R8 and R10, realization are used for Conversion of the Transistor-Transistor Logic level to RS232 level.

Show that 2 tunnels extend in Fig. 2, remaining expanded circuit is consistent with 2 tunnels demonstrated in Figure 2, the analog switch chip For HCF4051 chips, the decoder chip is 74HC138 chips, realizes 8 Bits Expandings；The input terminal of the HCF4051 chips Mouth X0 ~ X7 is separately connected 8 the first level shifting circuits of tunnel；Port INH, GND and VEE of the HCF4051 chips are grounded；Institute The port VCC for stating HCF4051 chips meets power supply VCC；Address choice port A, B, C of the HCF4051 chips are all connected with micro- place The ends I/O of device are managed, realize the selection of eight tunnels input；The port x of the HCF4051 chips connects the ports RXD of microprocessor, realizes The signal that input terminal is corresponded to according to the signal behavior of address selection port is sent to the ports RXD.Three or the eight decoder 74HC138 Output port Y0 ~ Y7 be separately connected eight road second electrical level conversion circuits；The address choice end of three or the eight decoder 74HC138 Mouth A, B, C are all connected with the ends IO of microprocessor, realize the selection of eight tunnels output；The port G1 of three or the eight decoder 74HC138, VCC meets power supply VCC；Port G2B and the VSS ground connection of three or the eight decoder 74HC138, three or the eight decoder 74HC138's Port G2A connects the ports TXD of microprocessor, realizes and corresponds to output end transmission data according to the signal behavior of address selection port. The receiving port RXD of external equipment_iThe emission port TXD of external equipment_iIt is used to connect the unlike signal end of same external equipment Mouthful.First optocoupler, the second optocoupler, third optocoupler and the 4th optocoupler select TLP785, the TLP785 include pin 1, Pin 2, pin 3 and pin 4,4 pins are respectively anode, cathode, emission port and current collection port.First optocoupler The pin 2 of pin 1 and the second optocoupler is grounded；The reception that the pin 2 of first optocoupler passes through the k of R3=2 Ω connection external equipments Port RXD_i；The pin 3 of first optocoupler and the pin 4 of the second optocoupler are connected in parallel any input in X0 ~ X7 of HCF4051 Port x_i；The pin 4 of first optocoupler passes through the Ω connection power supplys VCC of pull-up resistor R1=100, the pin of second optocoupler 3 ground connection.The pin 1 of the third optocoupler by pull-up resistor R6=1k Ω connection power supply VCC, pin 2 connect the Y0 of 74HC138 ~ Either output port Y in Y7_i, the emission port TXD of the connection external equipment of pin 3_i, 4 connections of pin+12V DC electricity；Described The pin 1 of four optocouplers is by the k of pull-up resistor R8=2 Ω connection power supply VCC, the pin 2 that pin 2 passes through phase inverter and third optocoupler It is connected in parallel 74HC138 output ports Y_i, pin 3 passes through the Ω of resistance R10=100, connection -12V DC electricity, pin 4 and third light The pin 3 of coupling is connected in the emission port TXD of external equipment in parallel_i；Wherein, the phase inverter selects 74HC04.This practicality is new Type, as extension gating is sent, not only realizes the expanded function of 1 expansion 8, while coordinating optocoupler using three or eight decoder 74HC138 The level shifting circuit of realization realizes the isolation of signal so that the load of microprocessor institute band mitigates significantly, micro- to improve The load capacity of processor is realized the extension of eight tunnels, is led to for receiving extension using MOS type chip HCF4051 as analog switch It crosses and signal isolation is realized using optocoupler level shifting circuit, while the high level of photoelectric coupled circuit is directly passed through 100 by power supply VCC Ω resistance drives, and low level is grounded by optocoupler, effectively solves the internal resistance of HCF4051 analog switches and influences, is further promoted Load capacity.

The operation principle of the utility model includes the extended method of the TXD of microprocessor and the extended method of RXD：Wherein, The extended method of TXD, specifically includes following steps：（1）The I/O port of the microprocessor exports AA, BB, CC selection signal, micro- place A (pin 1), B (pin 2), the C (pin 3) for managing I/O port output AA, BB, CC and 74HC13 of device are electrically connected, and selection signal is real Existing 8 select 1；（2）By the enabled input terminal G1 of 74HC138（Pin 6）Power supply VCC is connected, input terminal G2B is enabled（Pin 5）Or G2A （Pin 4）Ground connection, as enabled input terminal G2B（Pin 5）When ground connection, input terminal G2A is enabled（Pin 4）Connect microprocessor The ports TXD；As enabled input terminal G2A（Pin 4）When ground connection, input terminal G2B is enabled（Pin 5）Connect the ends TXD of microprocessor Mouthful；（3）When microprocessor exports AA, BB, CC select any channel Y in Y1 ~ Y7_iWhen, as AA=0, BB=0, CC=0, then select Channel Y0, as AA=0, BB=0, CC=1, then selector channel Y1, as AA=0, BB=1, CC=0, then selector channel Y2, when AA= When 0, BB=1, CC=1, then selector channel Y3, as AA=1, BB=0, CC=0, then selector channel Y4, when AA=1, BB=0, CC=1 When, then selector channel Y5, as AA=1, BB=1, CC=0, then selector channel Y6, as AA=1, BB=1, CC=1, then selector channel Y7 enables 74HC138, makes Y when TXD outputs are 0_iChannel output 0；When TXD outputs 1,74HC138 is not enabled, and output is complete 1, for Y at this time_iChannel is just 1, and it is identical to realize the signal that TXD port signals and 74HC138 are exported；As the Y of 74HC138_i When channel exports low level, the Q3 conductings of third optocoupler, the 4th optocoupler Q4 cut-offs, the emission port TXD of external equipment_iFor 12V；When The Y of 74HC138_iWhen channel exports high level, the Q3 cut-offs of third optocoupler, the Y of 74HC138_iChannel signal exports 0 by reverser Make the 4th optocoupler Q4 conductings, the emission port TXD of external equipment_iFor -12V, RS232 level demands are fully met.In this practicality In novel, RS232 level signals are directly provided by power supply VCC through optocoupler, and signal waveform is stablized, carrying load ability and anti-interference energy Power is strong.

The extended method of RXD, specifically includes following steps：（a）I/O port output AA, BB, CC selection of the microprocessor Signal realizes that 8 select 1；（b）By the ports the VCC ports connection power supply VCC, the VEE ground connection of HCF4051, the ports INH and GND ground connection, X Port connects the ports RXD of microprocessor；（c）When microprocessor output AA, BB, CC select input port X1 ~ X7 of HCF4051 In either port X_iPort, as AA=0, BB=0, CC=0, then selector channel X0 is then selected as AA=0, BB=0, CC=1 Channel X1, as AA=0, BB=1, CC=0, then selector channel X2, as AA=0, BB=1, CC=1, then selector channel X3, when AA= When 1, BB=0, CC=0, then selector channel X4, as AA=1, BB=0, CC=1, then selector channel X5, when AA=1, BB=1, CC=0 When, then selector channel X6, as AA=1, BB=1, CC=1, then selector channel X7, as the receiving port RXD of external equipment_iBy outer If export the logic level 1 i.e. output voltage V0 of external equipment between -3v~-15v, the first optocoupler Q1 conductings, output voltage V0 is sent into the X of HCF4051 by resistance R1_iPort, after be sent to the ends RXD of microprocessor, the RXD terminations of microprocessor receive height Level；As the receiving port RXD of external equipment_iBy peripheral hardware output logic level 0 be external equipment output voltage V0 be+3~+ 15v voltages, the second optocoupler Q2 conductings, the first optocoupler Q1 end, then the X of HCF4051_iMouthful be low level, after be sent to microprocessor The ends RXD, the ends RXD of microprocessor are low level.

The serial expanded circuit of the utility model can effectively realize the extension of the ports microprocessor RXD and TXD, utilize light Coupling element realizes TTL and RS232 level conversions, not only realizes signal transmitting, but also also improve load capacity, realizes light It is electrically isolated, and impact resistance, promotes the interference free performance of circuit extension.

The above is preferred embodiments of the present invention, it is noted that for the ordinary skill of the art For personnel, under the premise of not departing from principle described in the utility model, it can also make several improvements and retouch, these improvement The scope of protection of the utility model is also should be regarded as with retouching.

Claims (7)

1. one kind loads by force jamproof serial expanded circuit, the serial expanded circuit be electrically connected at microprocessor RXD, On the ports TXD and I/O, which is characterized in that by analog switch chip, decoder chip, be electrically connected in analog switch core Multiple first level shifting circuits of multiple data input pins of piece and multiple outputs in decoder chip are electrically connected Multiple second electrical level conversion circuits composition at end, realizes microprocessor input, the extension of output port；

The ports RXD of the output end connection microprocessor of the analog switch chip, the address input end of the analog switch chip The ports I/O of microprocessor are connected, the data input pin of the analog switch chip passes through multiple first level shifting circuits respectively It is electrically connected the receiving port RXD of external equipment_i, realize the extension of microprocessor input mouth；

The ports TXD and I/O of the input terminal electrical connection microprocessor of the decoder chip, the output end of the decoder chip The emission port TXD for connecting external equipment is electrically connected by multiple second electrical level conversion circuits respectively_i, realize microprocessor The extension of output port；

First level shifting circuit, including the first optocoupler Q1, second optocoupler Q2, R1 and R3 realize RS232 level to TTL The conversion of level；

The second electrical level conversion circuit, including third optocoupler Q3, the 4th optocoupler Q4, phase inverter, R6, R8 and R10, realization are used for Conversion of the Transistor-Transistor Logic level to RS232 level.

2. one kind according to claim 1 loads by force jamproof serial expanded circuit, which is characterized in that the simulation is opened Pass chip is HCF4051 chips, and the decoder chip is 74HC138 chips, realizes 8 Bits Expandings.

3. one kind according to claim 2 loads by force jamproof serial expanded circuit, which is characterized in that described Input port X0 ~ X7 of HCF4051 chips is separately connected 8 the first level shifting circuits of tunnel；The port of the HCF4051 chips INH, GND and VEE are grounded；The port VCC of the HCF4051 chips meets power supply VCC；It selects the address of the HCF4051 chips The ends I/O that port A, B, C are all connected with microprocessor are selected, realize the selection of eight tunnels input；The port x of the HCF4051 chips connects The ports RXD of microprocessor realize that the signal that input terminal is corresponded to according to the signal behavior of address selection port is sent to the ends RXD Mouthful.

4. one kind according to claim 2 loads by force jamproof serial expanded circuit, which is characterized in that described 38 translate Output port Y0 ~ Y7 of code device 74HC138 is separately connected eight road second electrical level conversion circuits；Three or the eight decoder 74HC138 Address choice port A, B, C be all connected with the ends IO of microprocessor, realize the selection of eight tunnels output；Three or eight decoder Port G1, VCC of 74HC138 meets power supply VCC；Port G2B and the VSS ground connection of three or the eight decoder 74HC138, described 38 The port G2A of decoder 74HC138 connects the ports TXD of microprocessor, realizes and is corresponded to according to the signal behavior of address selection port Output end transmission data.

5. one kind according to claim 4 loads by force jamproof serial expanded circuit, which is characterized in that first light It includes pin 1, pin 2,3 and of pin that coupling, the second optocoupler, third optocoupler and the 4th optocoupler, which select TLP785, the TLP785, Pin 4,4 pins are respectively anode, cathode, emission port and current collection port.

6. one kind according to claim 5 loads by force jamproof serial expanded circuit, it is characterised in that：First light The pin 1 of coupling and the pin 2 of the second optocoupler are grounded；The receiving terminal that the pin 2 of first optocoupler passes through R3 connection external equipments Mouth RXD_i；The pin 3 of first optocoupler and the pin 4 of the second optocoupler are connected in parallel any input terminal in X0 ~ X7 of HCF4051 Mouth X_i；The pin 4 of first optocoupler is grounded by pull-up resistor R1 connection power supplys VCC, the pin 3 of second optocoupler；Its In, R1 is 100 Ω, and R3 is 2 k Ω.

7. one kind according to claim 6 loads by force jamproof serial expanded circuit, it is characterised in that：The third light For the pin 1 of coupling by pull-up resistor R6 connection power supply VCC, pin 2 connects either output port Y in Y0 ~ Y7 of 74HC138_i, draw Foot 3 connects the emission port TXD of external equipment_i, 4 connections of pin+12V DC electricity；The pin 1 of 4th optocoupler passes through pull-up Resistance R8 connection power supply VCC, pin 2 are connected in parallel 74HC138 output ports Y by the pin 2 of phase inverter and third optocoupler_i, Pin 3 is electric by resistance R10 connections -12V DC, and the pin 3 of pin 4 and third optocoupler is connected in the transmitting of external equipment in parallel Port TXD_i；Wherein, R6 is 1k Ω, and R8 is that 2 k Ω, R10 are 100 Ω, and the phase inverter selects 74HC04.