KR960009912B1 - Serial communication apparatus - Google Patents

Abstract

transmission and reception lines for transmitting and receiving a data; a transmission line extending section (10) having a number of extended transmission lines; a reception line extending section (20) having a number of extended reception lines; and a line section signal generator (30) for outputting a selection signal in response to a line selection data received from a micro-processor or a micro-controller. The system enables to use an asynchronous serial input/output signal as if it were a number of asynchronous serial I/O signals.

Description

Communication line expansion device of serial communication device

1 is a block diagram of a serial communication apparatus using a microprocessor according to a first embodiment of the prior art.

2 is a block diagram of a serial communication apparatus using a microcontroller according to a second embodiment of the prior art.

3 is a block diagram of a communication line expansion device of a serial communication device according to the present invention.

4A to 4C are waveform diagrams for explaining the operation of FIG.

FIG. 5A is a first embodiment of the transmission line extension of FIG. 3. FIG.

5B is a first embodiment of the receiving line extension of FIG.

6A is a second embodiment of the transmission line extension of FIG.

6B is a second embodiment of the receiving line extension of FIG.

* Explanation of symbols for main parts of the drawings

1: Microprocessors 2 and 3: Bus Interface

4: Serial communication controller 5: Micro controller

6: Serial communication device 10: Transmission line extension

20: receiving line expansion unit 30: line selection signal generator

The present invention relates to a communication line extension device of a serial communication device, and more particularly, to a communication line extension device of a serial communication device configured to extend a communication line of a serial communication device by configuring a transmission and reception line extension unit to a serial communication device. .

In general, a serial communication apparatus using a conventional microprocessor is configured as shown in FIG. That is, in the microcomputer system, the bus interface 3 of the serial communication controller 4 is connected to the bus interface 2 of the microprocessor 1 by the bus B to configure the serial communication device 6. The serial communication device 6 communicates with another serial communication device or a terminal device (not shown) through communication lines T and R for transmitting and receiving communication information together with the control signal C.

In addition, a serial communication apparatus using a conventional microcontroller is configured as shown in FIG. That is, the serial communication device 6 is configured in the microcontroller 5 to communicate with other communication devices.

The configuration of FIGS. 1 and 2 described above is limited to the number of other real communication devices or terminal devices connected through the communication line T.R of the serial communication device 6.

That is, when the microcomputer system or microcontroller system having a serial communication device is used, when the number of serial communication lines is insufficient or when it is necessary to connect with a plurality of other serial communication devices, FIG. 1 shows a serial communication controller (4). The number of communication lines can be increased depending on the number of communication lines and the type of serial communication controller 4, but the cost of extending the serial communication line, the addition of hardware, and the addition of software are followed. In addition, when only one serial communication device is connected and used at a time without connecting a plurality of serial communication devices, low efficiency due to the use of the serial communication line and cost due to the system configuration are raised.

In FIG. 2, since the number of communication lines TR of the serial communication device 6 is limited depending on the type of the microcontroller 5, the number of lines can be increased only by the method shown in FIG. .

Accordingly, an object of the present invention is to connect a transmission line extension unit and a reception line extension unit to a communication line of a serial communication device, and connect a line selection signal generator to each of the transmission line extension units to establish a communication line of one asynchronous serial communication device. The present invention provides a device that extends to a plurality of asynchronous communication lines.

The present invention for achieving this object is a transmission line (T) and receiving line (R) of the serial communication device connected to the serial communication device (6) controlled by a microprocessor or microcontroller to transmit and receive data, and the serial A transmission line extension section 10 having a plurality of transmission lines T1, T2, ..., Tn connected to the transmission line T to extend the number of transmission lines T of the communication apparatus, and the serial; A reception line extension section 20 having a plurality of reception lines R1, R2, ..., Rn connected to the reception line R to expand the number of reception lines R of the communication apparatus, and the transmission; A plurality of extended communication lines T1 and R1, T2 and R2, ..., Tn connected to the communication line T and R of the serial communication device, respectively, connected to the line extension unit 10 and the receiving line extension unit 20, respectively. Rn) to selectively connect any one of communication lines A croissant processor or microcontroller receives each pass selected data characterized by comprising a track selection signal generator 30 for outputting a selection signal.

Hereinafter, the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram showing the configuration of a communication line expansion device of a serial communication device according to the present invention, and includes a transmission and reception line for transmitting and receiving data to and from a serial communication device 6 controlled by a microprocessor or a microcontroller. T and R), and in order to extend the number of transmission lines T of the serial communication apparatus 6 to the plurality of transmission lines, the transmission line extension 10 is connected to the transmission line T to thereby expand the plurality of transmission lines ( T1, T2, ..., Tn), and in order to extend the number of receiving lines R of the serial communication apparatus 6 to the plurality of receiving line lines, the receiving line extending unit 20 is connected to the receiving line R to expand the number. Communication lines T1, R1, T2, R2, ..., ..., which are formed to receive the receiving lines R1, R2, ..., Rn, and which are expanded on the communication lines T and R of the serial communication device 6. Tn and Rn) to selectively connect any communication line Receiving the selected data track of the croissant processor or microcontroller is configured to connect the line selection signal generator 30 for outputting a selection signal to each of the transmission line extended section 10 and can sinseollo extension 20. The

Each of the communication lines T1 and R1, T2 and R2, ..., Tn, which are expanded in plural numbers by the transmission / reception line expansion units 10 and 20 connected to the communication lines T and R of the serial communication device 6; And another serial communication device or terminal device (not shown) are connected respectively to Rn).

Referring to FIGS. 4A to 4C, waveforms which appear in respective cases with respect to signals appearing on the input or output terminals of the communication line of the serial communication apparatus according to the configuration of FIG. 3 will be described as follows.

4A shows a normal state in which the line of an input or output terminal is connected but no data is transmitted and received in serial communication. FIG. 4B is a line disconnection in which the line of an input or output terminal is connected but no data is transmitted and received in serial communication. A signal is shown, and FIG. 4C shows a signal when normal data is transmitted and received in asynchronous serial communication. Here, the electrical characteristics on the line indicating the start of data are recognized as the signal changes from H to L, and the end of the data is 1 bit or 1.5 bits depending on the number of bits of data transmitted / received for the asynchronous communication in which the electrical characteristics on the line are selected to H state. Or by retaining more than 2 bits.

Therefore, the electrical characteristics of the input or output terminals of the extended communication lines T1 and R1, T2 and R2, ..., Tn and Rn as shown in FIG. 3 are inputted in serial communication as shown in FIG. 4A. Alternatively, it is required that the terminal of the output is in a normal state in which a line is connected but no data is transmitted and received, and a state in which the line is disconnected as shown in FIG. 4B causes a problem in serial communication.

Referring to FIGS. 5A and 5B and FIGS. 6A and 6B with reference to the configuration of FIG. 3 and the signal waveforms of FIGS.

5 and 5B show a logic circuit in which one serial input / output line is expanded and multiplexed into a plurality of serial input / output lines as a first embodiment of the present invention.

5A illustrates the configuration of the transmission line extension unit 10 of FIG. 3 as a logic circuit. The transmission line T of the serial communication apparatus 6 includes the first OR gate G1 and the second OR gate ( G3) to n-th OR gates G5, respectively, and each of the plurality of lines E1, E2, ..., En of the line selection signal generator 30 is connected to the first inversion gate G2, 2 is connected to the other input terminal of the first, second to nth OR gates G1, G3 to G5 through each of the second inversion gate G4 to the nth inversion gate G6, and the first OR gate An extended transmission line T1 is connected to an output terminal of G1, an extended transmission line T2 is connected to an output terminal of the second OR gate G3, and an output terminal of the nth OR gate G5 is thus connected. The nth extended transmission line (Tn) is connected to this configuration.

FIG. 5B illustrates the configuration of the receiving line expansion unit 20 of FIG. 3 as a logic circuit, and each of the plurality of extended receiving lines R1, R2,..., And Rn includes a plurality of AND gates G7 and G8 to FIG. G9) is connected to each input terminal, and each of the plurality of lines E1, E2, ..., En of the line selection signal generator 30 is connected to each other input terminal of the plurality of AND gates G7, G8 to G9. A plurality of output lines are respectively connected from an output terminal of each of the plurality of AND gates G7 and G8 to G9 to an input terminal of an OR gate G10, and a serial communication device is connected to an output terminal of the OR gate G10. It is configured by connecting the receiving line (R) of 6).

An operation for selecting any one of a plurality of extended serial communication lines T1 and R1, T2 and R2, ..., Tn and Rn based on the configuration of FIGS. 5A and 5B will be described below. same.

The line selection signal generation unit selects for the communication lines T and R of the serial communication device 6 to be connected to any one of the communication lines T1 and R1, T2 and R2, ..., Tn and Rn. Determined by (30).

For example, when the communication lines T and R of the serial communication device 6 are to be connected with any of the extended communication lines Tn and Rn, the transmission line T of the serial communication device 6 and In order to allow communication between any of the extended transmission lines Tn, the asynchronous serial output signal T is transmitted from the serial communication device 6 to the transmission line extension section 10, and the line selection signal generation section 30 Receives a line selection data of a microprocessor or a microcontroller and decodes the plurality of selection signals E1, E2,. , When the selected selection signal En among the En signals is H and the remaining selection signals are set to L state and transmitted to the transmission line extension unit 10, the output signal T is applied only to the extended transmission line Tn connected to the output terminal of the OR gate G5. In addition, since the extended transmission line connected to the remaining output terminals is in the H state, communication is possible between the transmission line T of the serial communication apparatus and the extended arbitrary transmission line Tn, and the transmission line Tn is Except for the transmission line, the normal state without data transmission is shown.

On the other hand, communication should also be made between the receiving line R of the serial communication device and an arbitrary receiving line Rn, which is transmitted by selecting the selected signal En among the plurality of selection signals as H and the remaining selection signals as L. As the communication is performed between the line T and the arbitrary extended transmission line Tn, the reception line extension unit 20 sets the selected signal En among the plurality of selection signals E1, E2, and En to H and the rest to L. And the signals R1, R2,... When Rn is transmitted to the receiving line extension 20, an Rn signal is generated at the output terminal of the AND gate G9, and the output terminals of the remaining AND gates are in an L state, and the signals Rn and L are OR gates G10. Rn, which is a signal of an arbitrary receiving line Rn extended to the receiving line R of the serial communication device connected to the output terminal, is generated, so that the receiving line R and the line selection signal generator 30 of the serial communication device are generated. Communication is performed between any of the reception lines Rn selected by.

That is, if the line selection signal generation unit 30 selects an arbitrary selection signal En to be H and the other selection signals to L, the arbitrary arbitrary extended communication lines Tn and Rn are selected so that the serial communication device 6 Communication with the communication lines (T and R).

However, in order to perform normal communication between the extended communication lines as described above, R1, R2,... Output to the transmission line T and the reception line R having the asynchronous serial output signal T are provided. The electrical characteristics of the extended receiving lines R1, R2, ..., Rn having Rn should be in the H state as shown in FIG. 4A.

6A and 6B show a logic circuit constituting two serial input / outputs using one control signal as a second embodiment of the present invention.

6A illustrates the configuration of the transmission line extension unit 10 of FIG. 3 as a logic circuit. The transmission line T of the serial communication apparatus 6 is connected to the first OR gate G11 and the second OR gate ( The line E of the line selection signal generator 30 to the other input end of the first OR gate G11 through the inversion gate G12, and the line E to the second end of the line E. An extended transmission line T1 is connected to an output terminal of the first OR gate G11 and an extended transmission line T1 is connected to an output terminal of the second OR gate G13. Configure by connecting T2).

6B illustrates the configuration of the receiving line extension unit 20 of FIG. 3 as a logic circuit. The extended receiving line R1 is connected to an input terminal of the first AND gate G14 and another extended receiving line R2 is illustrated in FIG. ) Is connected to the input terminal of the second AND gate G15, and the line E of the line selection signal generator 30 is connected to the other input terminal of the first AND gate G14, and the line E is removed. The other input terminal of the 1 AND gate G14 and the line E are connected to the other input terminal of the second AND gate G15 through the all gate G16, and the first AND gate G14 and the second terminal. The output line is connected to the input terminal of the OR gate G17 from the output terminal of the AND gate G15, and the receiving line R of the serial communication device 6 is connected to the output terminal of the OR gate G17. .

An operation for selecting the extended serial communication lines T1 and R1, T2 and R2 based on the configuration of FIGS. 6A and 6B will be described below.

The selection for connecting the communication lines T and R of the serial communication device 6 to any one of the two extended communication lines T1 and R1, T2 and R2 is determined by the line selection signal generator 30. do.

For example, when the communication lines T and R of the serial communication device 6 are to be connected to the extended communication lines T1 and R1, first, the transmission line T and the extended transmission line of the serial communication device 6 are connected. In order to make communication between T1, the asynchronous serial output signal T is transmitted from the serial communication device 6 to the transmission line extension unit 10, and the line selection signal generation unit 30 is a microprocessor or a microcontroller. When the selection signal E is received and the selection signal E is selected as H, and the control signal is sent to the transmission line extension unit 10, the output signal T is extended to the extended transmission line T1 connected to the output terminal of the OR gate G11. Since the extended transmission line T2 connected to the output terminal of the OR gate G13 is in the H state, the output signal of the transmission line T2 of the serial communication device enables data transmission through the extended transmission line T1. do.

On the other hand, communication must be performed through the receiving line R and the extended receiving line R1 of the serial communication apparatus, which is selected through the transmission line T1 in which the transmitting line T is extended by selecting the selection signal E as H. As the communication is made, the selection signal E is transmitted to the receiving line expansion unit 20 in the H state, and is output from the extended receiving lines R1 and R2 to the receiving line R of the serial communication device 6. When the signals R1 and R2 are transmitted to the receiving line extension 20, an R1 signal is generated at the output terminal of the AND gate G14, and an L state is output at the output terminal of the AND gate G15, and the signals R1 and L are OR gates. Since R1, a signal of the extended receiving line R1, is generated at the receiving line R of the serial communication device connected to the output terminal by G17, the receiving line R of the serial communication device is extended to the receiving line R1. Communication is performed.

That is, when the selection signal E is selected as the H from the line selection signal generator 30, the extended communication lines T1 and R1 are selected to be connected to the communication lines T and R of the serial communication device 6 to communicate. Will be done.

If another extended communication lines T2 and R2 are selected to communicate with the communication lines T and R of the serial communication device, the selection signal E may be selected as L from the line selection signal generator 30.

However, in order to achieve normal communication between the extended communication lines as described above, the extended reception lines R1 and R1 having a transmission line T having an asynchronous serial output signal T and a signal R1 or R2 outputted to the reception line R are provided. The electrical characteristics on the line of R2) should be in H state as shown in Figure 4A.

As described above, the present invention configures one asynchronous serial communication line of a serial communication device to form two or more extended communication lines by using a transmission / reception line expansion unit and a line selection signal generation unit, thereby selecting the line selection signal generation unit. The control signal can be connected to the serial communication line of the serial communication device and one of the extended communication lines so that the asynchronous serial I / O signal of the serial communication device can be used as if having multiple asynchronous serial I / O signals. In addition, according to the communication protocol between the serial communication device and the terminal devices connected to the extended serial communication line and the adjustment of the selection signal of the extended serial communication line, the line extension of the serial communication device and the multiplexing of several asynchronous serial communication lines can be performed. You can do it.

Claims (6)

A serial communication apparatus communicating with an asynchronous serial communication system, comprising: a serial communication apparatus transmission line (T) and a reception line (R) connected to a serial communication apparatus (6) controlled by a microprocessor or a microcontroller to transmit and receive data. A transmission line extension unit 10 having a plurality of transmission lines T1, T2, ..., Tn connected to a transmission line T so as to extend a plurality of transmission lines T of the serial communication apparatus; And a receiving line extension unit 20 having a plurality of receiving lines R1, R2, ..., Rn connected to the receiving line R to expand the plurality of receiving lines R of the serial communication apparatus. And a plurality of communication lines T1 and R1, T2 and R2 connected to the transmission line extension unit 10 and the reception line extension unit 20, respectively, and extended to the communication lines T and R of the serial communication device. …, Select one of the communication lines (Tn and Rn) Microprocessor or the communication line of the expansion unit receiving a selected track data from the microcontroller serial communication apparatus which comprises a track selection signal generator 30 for outputting a selection signal to connect to. The transmission line extension unit 10 of claim 1, further comprising a plurality of OR gates and a plurality of inverting gates to connect a transmission line T of a serial communication device to each input terminal of the plurality of OR gates. A plurality of lines E1, E2, ..., En of the line selection signal generation unit 30 are connected to respective input terminals of the plurality of OR gates through each of the plurality of inverting gates, A communication line expansion device for a serial communication device, comprising a plurality of transmission lines (T1, T2, ..., Tn) connected to each output terminal. The receiver line extension unit 20 connects a plurality of extended reception lines R1, R2, ..., Rn to each input terminal of the plurality of AND gates, and each of the other AND gates. Connect a plurality of lines (E1, E2, ..., En) of the line selection signal generator 30 to an input terminal of the plurality of output lines, and connect a plurality of output lines to the input terminals of the OR gate from each output terminal of the plurality of AND gates, respectively. And a receiving line (R) of the serial communication device (6) connected to the output terminal of the OR gate. A transmission line (T) and a reception line (R) of a serial communication device connected to the serial communication device (6) for transmitting and receiving data, and two transmission lines (T) of the serial communication device. A transmission line extension section 10 having two transmission lines T1 and T2 connected to a transmission line T for expansion, and a reception line for extending two reception lines R of the serial communication apparatus. Connected to (R) and connected to a receiving line extension section 20 having two receiving lines R1 and R2, and to the transmission line extension section 10 and the receiving line extension section 20, respectively, And a line selection signal generator 30 for selectively connecting any one of two communication lines T1 and R1, T2, and R2 to the communication lines T and R of the communication device. Communication line expansion device of serial communication device. The transmission line expansion unit 10 connects the transmission line T of the serial communication apparatus to each input terminal of the first and second OR gates, and the other of the first OR gate through the inversion gate. The line E of the line selection signal generator 30 is connected to an input terminal and another input terminal of the second OR gate, and two transmission lines T1, which are extended to two output terminals of the first and second OR gates, respectively. Communication line expansion device of the serial communication device, characterized in that configured by connecting each T2). The reception line extension unit 20 of claim 1, wherein the reception line extension unit 20 includes a reception line R1 extended to an input terminal of the first AND gate and a line selection signal generator 30 to another input terminal of the first AND gate. The line E of the line selection signal generator 30 is connected to the line E, through the other extended receiving line R2 at the input terminal of the second AND gate, and an inverted gate at the other input terminal of the second AND gate. , Two output lines are respectively connected to the input terminal of the OR gate from the output terminals of the first and second AND gates, and the receiving line R of the serial communication device 6 is connected to the output terminal of the OR gate. Communication line expansion device of a serial communication device, characterized in that the configuration.