KR102098467B1 - Output signal automatic controller for RS-232 and RS-422 and RS-485 serial communication - Google Patents

Abstract

The present invention relates to RS-232, RS-422, and RS-485 selection and automatic control of output signals. The output signal control device for serial communication is set to a value that selects a line interface of any one of a plurality of transceivers. An interface mode selection value is generated according to at least one of a value of a dip switch and a value of the interface mode register, a value of a dip switch, and a value of a received signal, which is set to a value of at least one of a register, an on state, and an off state, and the interface And a line interface control unit controlling each of the plurality of transceivers according to a mode selection value

Description

RS-232, RS-422, RS-485 selection and output signal automatic controller for RS-232 and RS-422 and RS-485 serial communication}

The present invention relates to RS-232, RS-422, RS-485 selection and automatic control of output signals.

RS-232, RS-422, and RS-485 serial interfaces are typically used for asynchronous serial communication systems. Asynchronous serial communication is handled by UART (Universal Asynchronous Receiver / Transmitter). UART means an asynchronous transceiver that provides interfaces such as RS-232, RS-422, and RS-485, and UART used in computers or general communication devices includes PCIe / PCI bus, USB bus, and local bus.

A typical UART outputs parallel data as serial data (SOUT) by receiving commands from a computer application or a program embedded in the device. The new UART, which is currently on sale, has many additional features in addition to those listed above.

Among them is the RS-485 control part. This part is a signal necessary for easy RS-485 communication control. Looking at NXP's SC16C850, the RTS signal line and the DTR signal line can be used as the Auto RS-485 RTS control signal AutoRS-485 signal.

When using the AutoRS-485 signal, there is no problem in attaching the RS-485 transceiver to the UART, but attach the RS-232 transceiver, RS-422 transceiver, and RS-485 transceiver on the same board only with the AutoRS-485 signal. Implementation circuitry is complex and requires additional components to select and use.

In the current market, low-cost equipment uses one of RS-232 transceivers, RS-422 transceivers, and RS-485 transceivers, but expensive equipment can be directly connected to the RS-232 transceiver, RS-422 transceiver, and RS-485 by the user. It is possible to directly select and use one of each interface of the transceiver.

For example, in case of an 8-port device server, a low-cost board supports only the entire 8-port RS-232 interface or only the full 8-port RS-485 interface.

However, if the user wants to use 4 of the 8 ports as an RS-232 interface, 2 ports as an RS-422 interface, and the remaining 2 ports as an RS-485 interface due to the on-site system configuration, each device has a separate interface for low-cost equipment. There is a problem that the device server must be purchased individually. However, in the case of an expensive device with RS-232, RS-422, and RS-485 transceivers at the same time, you can set the desired interface for each port, so you can purchase only one device server with RS-232, RS-422, and RS-45 transceivers at the same time. May be

According to the present invention, RS-232 transceivers, RS-422 transceivers, and RS-485 transceivers can be selectively attached to the same board with only AutoRS-485 signals, so that it is not necessary to purchase communication equipment such as device servers for each line interface. It aims to provide -232, RS-422, RS-485 selection and automatic control of output signals.

An object as described above is an interface mode register set to a value for selecting a line interface of any one of a plurality of transceivers; A dip switch set to a value of at least one of an on state and an off state; And a line interface control unit generating an interface mode selection value according to at least one of a value of the interface mode register, a value of a dip switch, and a value of a received signal, and controlling each of the plurality of transceivers according to the interface mode selection value. Characterized in that, RS-232, RS-422, RS-485 selection and output signal is achieved by an automatic controller.

In the above embodiment, the circuit interface controller determines any one of the value of the interface mode register and the value of the dip switch according to MODE_SELECT among the received signals as an interface mode selection value, and the interface mode selection value is Accordingly, it is characterized in that the mode selection signal is generated.

In the above embodiment, the circuit interface controller activates any one of the plurality of transceivers, the RS-232 transceiver, the RS-422 transceiver, and the RS-485 transceiver, and deactivates the remaining transceivers according to the interface mode selection value. And generating the mode selection signal.

According to an embodiment of the present invention, an RS-232 transceiver, an RS-422 transceiver, and an RS-485 transceiver can be selectively attached to the same board with only the AutoRS-485 signal, so that communication equipment such as a device server can be interfaced. It has the advantage of not having to purchase individually.

1 is a diagram showing the structure of a UART internal register for a typical local bus.
2 is a diagram showing timing between SOUT and AutoRS-485 signals.
3 to 5 are diagrams for explaining RS-232, RS-422, and RS-485 transceivers.
6 is a view for explaining a block diagram of a circuit interface control unit.
7 is a view for explaining a process of selecting one of the values of the IMR and DIP SW and outputting it as an interface mode selection value.
FIG. 8 is a 4X1 MUX generating an RS-232_SOUT_EN_SIN_EN signal according to the interface mode selection value of FIG. 7.
FIG. 9 is a 4X1 MUX generating an RS-422_SOUT_EN signal according to the interface mode selection value of FIG. 7.
FIG. 10 is a 4X1 MUX generating an RS-422_SIN_EN signal according to the interface mode selection value of FIG. 7.
FIG. 11 is a 4X1 MUX generating an RS-485_SOUT_EN signal according to the interface mode selection value of FIG. 7.
FIG. 12 is a 4X1 MUX generating an RS-485_SIN_EN signal according to the interface mode selection value of FIG. 7.
13 is a 4X1 MUX generating an SIN signal according to the interface mode selection value of FIG. 7.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings.

1 is a diagram showing the structure of a UART internal register for a typical local bus.

Referring to FIG. 1, a typical UART receives a command from a computer application or a program embedded in a device and outputs parallel data as serial data (SOUT). The corresponding SOUT output structure is shown in FIG. 1. [Table 1] below shows the structure of UART internal register for general local bus.

In Table 1, the receive buffer register is a register used to read one character of data from outside. The transfer wait register is a register used to transfer data of one character. The interrupt enable register is a register that generates various interrupts. The interrupt status register is a register that indicates the interrupt status that occurred inside the UART. The FIFO (First-In First-Out) control register is a register used to control the FIFO buffer.

The line control register is used to control the number of data bits, the number of stop bits, and the parity bit, but when LCR [7] = '1', the register for setting the communication speed can be used. In other words, it is possible to use a divisor latch instead of the receive buffer register, transmit wait register, and interrupt enable register.

The modem control register is a register used to control the modem signal line request to send (RTS) and data terminal relay (DTR). The line status register is a register that indicates the status of data input to the receive buffer register. The modem status register is a register indicating the modem status.

In FIG. 1, the beam generator 10 (Baud Generator) receives an external clock to generate a desired communication speed. In general, the beam generator 10 uses a clock that is 1/8 times or 1/16 times the frequency input from the outside as a basic minimum clock.

The reason for this is to create a sampling clock for detecting the input serial data when the external serial data is input to the UART. However, detailed descriptions thereof will be omitted because these contents are irrelevant to the present invention.

For example, if a 1 / 16x clock is used as the basic minimum clock, 14,745,600 / 16 = 921,600Hz when a 14.7456MHz frequency is input externally, which becomes the maximum communication speed of the corresponding UART.

The beam generator 10 determines the UART communication speed according to the value set in the device latch in the UART. That is, if the device latch is set to 1, the communication speed is 921,600 / 1 = 921,600bps, and when the device latch is set to 96, the communication speed is 921,600 / 96 = 9600bps.

The communication clock generated by the beam generator 10 is provided to the transmission time control unit 20.

The transmission time control unit 20 (Transmit Timing & Control) drives the Transmit Shift Register 30 according to the communication clock received from the beam generator 10.

The transfer transfer register 30 serializes data input in parallel from the transfer wait register 40 or the transmit FIFO 50 in synchronization with the communication clock generated by the beam generator 10 under the control of the transfer time control unit 20. Convert to data and transmit the serial communication output signal (SOUT) to the outside.

The new UART, which is currently on sale, has many additional features in addition to those listed above. Among them is the RS-485 control part. This part is a signal necessary for easy RS-485 communication control. Looking at SC16C850 of NXP, RTS signal line and DTR signal line can be used as Auto RS-485 RTS control signal.

The contents are controlled by the AFCR2 register of SC16C850. [Table 2] below shows the contents related to Auto RS-485 RTS control among AFCR2 register contents.

To use the RTS pin as an Auto RS-485 Control pin based on Table 2 above, set AFCR2 [4] = '1', AFCR2 [3] = '0', AFCR2 [0] = '1' . The value of AFCR2 [5] can be set according to the types of externally mounted RS-422 and RS-485 transceivers. The Auto RS-485 Control signal from the RTS pin is hereinafter called AutoRS-485.

There are four timing charts between SOUT and AutoRS-485 signals. This process will be described in more detail with reference to FIG. 2 below.

2 is a diagram showing timing between SOUT and AutoRS-485 signals.

Referring to FIG. 2, when AFCR2 [5] is set to “1”, timing between SOUT and AutoRS-485 signals can be implemented in four ways as shown in FIG. 2. 2 is not limited to the timing chart of NXP's SC16C850, and is a diagram of various UART output methods.

When using the above AutoRS-485 signal, there is no problem in attaching the RS-485 transceiver to the UART, but attach the RS-232, RS-422, and RS-485 transceivers on the same board only with the AutoRS-485 signal. Implementation circuitry is complex and requires additional components to select and use.

In the current market, low-cost equipment uses one of RS-232 transceivers, RS-422 transceivers, and RS-485 transceivers, but expensive equipment can be directly connected to the RS-232 interface, RS-422 interface, and RS-485 by the user. It is possible to select and use one of the interfaces directly.

For example, in the case of an 8-port device server, low-cost equipment supports only the entire 8-port RS-232 interface or only the entire 8-port RS-485 interface.

However, if the user wants to use 4 of the 8 ports as an RS-232 interface, 2 ports as an RS-422 interface, and the remaining 2 ports as an RS-485 interface due to the on-site system configuration, each interface has a low-cost device. Device servers must be purchased separately.

However, if 8 ports can select RS-232 interface, RS-422 interface, or RS-485 interface for each port, you only need to purchase one device server. For this reason, the present invention has an AutoRS-485 signal that is easy to use only for the RS-485 interface, and installs an RS-232 transceiver, an RS-422 transceiver, and an RS-485 transceiver on the same board, allowing the user to select them. It provides RS-232, RS-422, and RS-485 selection and automatic control of output signals.

3 to 5 are diagrams for explaining RS-232, RS-422, and RS-485 transceivers.

3 to 5, FIG. 3 is a diagram showing an RS-232 transceiver MAX3243 logic circuit, FIG. 4 is a diagram showing an RS-422 transceiver MAX3086 logic circuit, and FIG. 5 is an RS-485 transceiver MAX3088 logic circuit. It is a drawing shown.

Table 3 is a table for describing the MAX3243 pin, and Table 4 is a table for describing the MAX3086 and MAX3088 pins.

The most commonly used connector is the DE-9 Pin Male connector when RS-232 transceivers, RS-422 transceivers and RS-485 transceivers are assigned to the same board and the same UART port.

The DE-9 Pin connector only provides 9 pins. In case of RS-232, a total of 9 signal lines such as TXD, RXD, RTS, CTS, DTR, DSR, DCD, RI, GND are used, and in case of RS-422, 4 signal lines such as TXD +, TXD-, RXD +, and RXD- are used. In case of RS-485, two signal lines such as TRXD + and TRXD- are used. Since all of these signal lines cannot be connected to the DE-9 Pin connector, only one of the RS-232 transceiver, RS-422 transceiver, and RS-485 transceiver can be used.

When using an RS-232 transceiver, the RS-422 transceiver and the RS-485 transceiver are in a shutdown state, when using the RS-422 transceiver, the RS-232 transceiver and the RS-485 transceiver are in a shutdown state, and the RS-485 transceiver is used. If necessary, the RS-232 transceiver and RS-422 transceiver must be shut down.

Since these control signals must be controlled together with the AutoRS-485 signal, an additional circuit configuration is required externally. Placing this circuit part in the UART and outputting RS-232, RS-422, and RS-485 control signals makes it easy to perform operations.

To this end, a specific register (hereinafter referred to as an 'interface mode register') in the UART (empty area in Table 1) or an interface pin (IMR, Interface Mode Register) is set as an external pin and it is used in various ways, such as a dip switch. Just take the value and process it. When receiving input from an external pin, it is recommended to use the smallest pin, so it is the most appropriate method to use only 2 bits.

Table 5 below is a table showing a line interface when a dip switch is used with the interface mode register and the corresponding external pin.

In Table 5, RS-485 4-line is used with the same structure as RS-422. The type of the line interface allocated to the above IMR value or the dip switch ON / OFF value is not fixed but can be allocated and used differently.

Combining the above values and AutoRS-485 signals to configure a logic circuit that can be used by selecting one of the RS-232 line interface, RS-422 line interface, and RS-485 line interface, forms a separate external circuit. There is no need to do.

In this case, the external RS-232 transceiver, the RS-422 transceiver, and the RS-485 transceiver should be placed at the same time, and the corresponding transceiver should be appropriately controlled using the AutoRS-485 signal, and the corresponding part is the circuit interface controller.

The line interface can be selected through the software program for setting by the interface mode register, and the line interface can be selected by turning on or off the dip switch installed in the product.

6 is a view for explaining a block diagram of a circuit interface control unit.

Referring to FIG. 6, the line interface control unit 610 has the interface mode register value (hereinafter referred to as 'IMR [1: 0]') and a dip switch value (hereinafter referred to as 'DIP SW [1') as shown in Table 5 above. : 0] '), IMR [1: 0] or DIP SW [1: 0] is determined as the interface mode selection value according to MODE_SELECT.

For example, if the MODE_SELECT value is '0', the value of IMR [1: 0] is used as the value for selecting the line interface type, and if it is '1', the value of DIP SW [1: 0] is selected for the line interface type. It is used as a value.

SOUT is a serial data signal line output from the transfer shift register 30 to SOUT in FIG. 1 and transmitted to the outside. This is directly output to LINE_SOUT of the line interface control unit 610 to be connected to the driver pin DI of the RS-232 transceiver 620, the RS-422 transceiver 630, and the RS-485 transceiver 640.

The SIN value is a serial data signal input to the receive transfer register in the UART, and the RS-232_SIN signal line of the RS-232 transceiver, the RS-422_SIN of the RS-422 transceiver 630, and the RS-485_SIN signal line of the RS-485 transceiver 640 It is a signal line that is output by selecting the serial data input from the line interface value.

The RS-422_MODE_SELECT input signal line is used to select whether to use the RS-422 operation method 1: 1 or multi-drop method. That is, if the RS-422_MODE_SELECT value is '0', the 1: 1 method is selected, and if it is '1', the multi-drop method is selected. Here, the RS-422_MODE_SELECT value can be used to the contrary.

The line interface control unit 610 generates a mode selection signal according to the interface mode selection value (that is, RS-232_SOUT_EN_SIN_EN, RS-422_SOUT_EN, RS-422_SIN_EN, RS-485_SOUT_EN, RS-485 SIN_EN signals, etc.) to generate RS. The -232 transceiver 620, the RS-422 transceiver 630, and the RS-485 transceiver 640 are controlled.

In one embodiment, SOUT and SIN are transmitted and received externally through the RS-232 transceiver 620, and when the external transmission and reception are not desired through the RS-422 transceiver 630 and the RS-485 transceiver 640, the above Based on [Table 5], set IMR [1: 0] to 00b or turn DIP SW [1: 0] off / off.

In the above case, the RS-422 transceiver 630 and the RS-485 transceiver 640 should not operate. To do this, only the RS-232 transceiver 620 is activated and the RS-422 transceiver 630 and the RS-485 transceiver 640 must be made inactive.

To this end, input '1' to the / FORCEOFF pin shown in FIG. 3 and Table 3 through the RS-232_SOUT_EN_SIN_EN pin to make the RS-232 transceiver 620 active (Forceon when not using the auto-powerdown function) '1'), '0' and '1' to the DE and / RE pins of the RS-422 transceiver 630 shown in FIG. 4 and Table 4 through RS-422_SOUT_EN and RS422-SIN_EN pins, respectively. The input is made into a low power shutdown state, and the RS-422 transceiver 630 is deactivated.

In addition, '0' and '1' are input to the DE and / RE pins of the RS-485 transceiver 640 shown in FIGS. 5 and 4 through RS-485_SOUT_EN and RS485-SIN_EN pins, respectively, to make a low-power shutdown state. The RS-485 transceiver 640 is made inactive.

Then, the RS-422 transceiver 630 and the RS-485 transceiver 640 have the same effect as not on the circuit, and only the RS-232 transceiver 620 operates.

In another embodiment, if you do not want to transmit and receive SOUT and SIN to the outside through the RS-422 transceiver 630, RS-232 transceiver 620 and the RS-485 transceiver 640 to the outside. Set IMR [1: 0] to 01b or turn DIP SW [1: 0] OFF / ON based on Table 5.

In this case, the RS-232 transceiver 620 and the RS-485 transceiver 640 should not operate. To do this, only the RS-422 transceiver 630 is activated, and the RS-232 transceiver 620 and the RS-485 transceiver 640 need only be made inactive.

To this end, when the RS-422 transceiver 630 is used in the multi-drop mode, an AutoRS-485 signal is input to the RS-422 transceiver 630 DE pin through the RS-422_SOUT_EN pin, and when used in the 1: 1 mode. Input '1' through RS-422_SOUT_EN pin. In addition, RS-422 transceiver 630 is activated by inputting '0' to the RS-422 transceiver 630 / RE pin through the RS-422_SIN_EN pin.

In addition, the RS-232 transceiver 620 is deactivated by inputting '0' to the / FORCEOFF pin of the RS-232 transceiver 620 through RS-232_SOUT_EN_SIN_EN to make it a shutdown state.

In addition, in case of the RS-485 transceiver 640, '0' and '1' are input to the DE and / RE pins through the RS-485_SOUT_EN and RS485-SIN_EN pins, respectively, to be shut down to disable the RS-485 transceiver 640. State.

Then, the RS-232 transceiver 620 and the RS-485 transceiver 640 have the same effect as not on the circuit, and only the RS-422 transceiver 630 operates.

There are two types of RS-485 two-wire communication modes: eco mode and non-echo mode.

In the Eco mode, '0' is always input to the / RE pin of the RS-485 transceiver 640, and when DE is '0', serial data from another RS-485 transceiver is received and DE is '1'. The serial data sent by the user is also input. In other words, the serial data that I output is directly inputted. At this time, if the other RS-485 transceiver does not send the serial data, the serial data sent by me will be input completely, and if another RS-485 transceiver sends the serial data, the data will collide. Occurred, the serial data I sent is not completely input.

That is, the eco mode makes it possible to check whether the serial data I have sent is properly transmitted to the other party.

The non-echo mode is commonly connected to the / RE pin and the DE pin of the RS-485 transceiver 640. In this case, the AutoRS-485 signal is output to the RS-485_SOUT_EN pin and RS-485_SIN_EN pin and input to the RS-485 transceiver 640 DE pin and / RE pin. When the AutoRS-485 signal is '1', it is connected to the DE pin. '1' input is input and '1' is input to / RE pin at the same time.

In this case, the output of the RS-485 transceiver 640 is activated, but the input is deactivated. That is, since the serial data that I sent is not re-entered, it is impossible to check whether the serial data that I sent does not collide and is properly transmitted to the other party. In this case, if the other party responds, it can be considered that the serial data has been properly transmitted. If the other party does not respond, it can be determined that the serial data has collided.

Alternatively, when '0' is output to the AutoRS-485 signal, '0' is input to the RS-485 transceiver 640 DE, and '0' is input to / RE to disable the output of the RS-485 transceiver 640. State, but the input is active. In this case, serial data sent from the RS-485 transceiver of the other side can be input.

In one embodiment, SOUT and SIN are transmitted and received externally through the RS-485 transceiver 640, but are used as a non-echo mode, and transmitted and received externally through the RS-232 transceiver 620 and the RS-422 transceiver 630. If you do not want the following, you can set IMR [1: 0] to 10b or set DIP SW [1: 0] ON / OFF based on Table 5.

In this case, only the RS-485 transceiver 640 may be activated in the non-echo mode, and the RS-232 transceiver 620 and the RS-422 transceiver 630 may be made inactive, to the DE pin of the RS-485 transceiver 640. AutoRS-485 signal is input through RS-485_SOUT_EN pin and AutoRS-485 signal is input to / RE pin through RS-485_SIN_EN pin to activate RS-485 transceiver 640 in non-echo mode.

In addition, the RS-232 transceiver 620 is deactivated by inputting '0' to the / FORCEOFF pin of the RS-232 transceiver 620 through RS-232_SOUT_EN_SIN_EN to make it a shutdown state. RS-422 transceiver 630 is disabled by inputting '0' and '1' to the DE and / RE pins of RS-422 transceiver 630 through RS-422_SOUT_EN and RS422-SIN_EN pins, respectively. To be.

Then, the RS-232 transceiver 620 and the RS-422 transceiver 630 have the same effect as not on the circuit, and only the RS-485 transceiver 640 operates.

In another embodiment, SOUT and SIN are transmitted and received externally through the RS-485 transceiver 640, but are used in the Echo mode, and transmitted and received externally through the RS-232 transceiver 620 and the RS-422 transceiver 630. If you do not want to do the following, you can set IMR [1: 0] to 11b or turn DIP SW [1: 0] ON / ON based on Table 5.

In this case, only the RS-485 transceiver 640 is activated in the Echo mode, and the RS-232 transceiver 620 and the RS-422 transceiver 630 need to be made inactive, but the RS-485 transceiver 640 DE pin is autoRS- The 485 signal is input through the RS-485_SOUT_EN pin, and '0' is input to the / RE pin through the RS-485_SIN_EN pin to activate the RS-485 transceiver 640 in eco mode.

In addition, the RS-232 transceiver 620 is deactivated by inputting '0' to the / FORCEOFF pin of the RS-232 transceiver 620 through RS-232_SOUT_EN_SIN_EN to make it a shutdown state. RS-422 transceiver 630 is disabled by inputting '0' and '1' to the DE and / RE pins of RS-422 transceiver 630 through RS-422_SOUT_EN and RS422-SIN_EN pins, respectively. To be.

Then, the RS-232 transceiver 620 and the RS-422 transceiver 630 have the same effect as not on the circuit, and only the RS-485 transceiver 640 operates.

7 is a view for explaining a process of selecting one of the values of the IMR and DIP SW and outputting it as an interface mode selection value.

Referring to FIG. 7, it is a 2X1 MUX that selects one of the values of IMR and DIP SW and outputs it as an interface mode selection value. If the MODE_SELECT value is '0', the value input to I0 is output as Y, and if the MODE_SELECT value is '1', the value input to I1 is output as Y. The circuit interface method is selected using the interface mode selection value 'IMS [1: 0]' created in Figure 7.

FIG. 8 is a 4X1 MUX generating an RS-232_SOUT_EN_SIN_EN signal according to the interface mode selection value of FIG. 7.

Referring to FIG. 8, it is a 4X1 MUX that generates an RS-232_SOUT_EN_SIN_EN signal according to the interface mode selection value 'IMS [1: 0]' of FIG. 7. When "00" is inputted to S1 and S0, the value inputted to I0 is outputted as Y. When "01" 'is inputted to S1 and S0, the value inputted to I1 is outputted as Y, and "10" to S1 and S0. When 'is input, the value input to I2 is output as Y, and when "11"' is input to S1 and S0, the value input to I3 is output as Y.

FIG. 9 is a 4X1 MUX generating an RS-422_SOUT_EN signal according to the interface mode selection value of FIG. 7.

Referring to FIG. 9, it is a 4X1 MUX that generates an RS-422_SOUT_EN signal according to the RS-422_MODE_SELECT value and the interface mode selection value of FIG. 7. Determine whether to use the RS-422 operation method 1: 1 or multi-drop by RS-422_MODE_SELECT, and operate the RS-422 transceiver by the interface mode selection value 'IMS [1: 0]' in FIG. 7 The way is decided.

FIG. 10 is a 4X1 MUX generating an RS-422_SIN_EN signal according to the interface mode selection value of FIG. 7.

Referring to FIG. 10, the operation method of the RS-422 transceiver is determined by the interface mode selection value 'IMS [1: 0]'.

FIG. 11 is a 4X1 MUX generating an RS-485_SOUT_EN signal according to the interface mode selection value of FIG. 7.

Referring to FIG. 11, an operation method of an RS-485 transceiver is determined by the interface mode selection value 'IMS [1: 0]'.

FIG. 12 is a 4X1 MUX generating an RS-485_SIN_EN signal according to the interface mode selection value of FIG. 7.

Referring to FIG. 12, the operation method of the RS-485 transceiver is determined by the interface mode selection value 'IMS [1: 0]'. If the interface mode selection value 'IMS [1: 0]' is "10", the RS-485 transceiver is operated in non-echo mode by outputting the AutoRS-485 value, and the interface mode selection value 'IMS [1: 0] If 'is' 11', '0' is output to implement operation of the RS-485 transceiver in eco mode.

13 is a 4X1 MUX generating an SIN signal according to the interface mode selection value of FIG. 7.

Referring to FIG. 13, the LINE_SOUT signal can be output by outputting the SOUT signal through a buffer or directly connecting it.

As described above, although the present invention has been described by limited embodiments and drawings, the present invention is not limited to the above embodiments, and various modifications and modifications from these descriptions will be made by those skilled in the art to which the present invention pertains. Deformation is possible. Accordingly, the spirit of the present invention should be understood only by the claims set forth below, and all equivalent or equivalent modifications thereof will be said to fall within the scope of the spirit of the present invention.

10: beam generator 20: transmission time control unit
30: transfer transfer register 40: transfer wait register
50: FIFO 610: line interface control unit
620: RS-232 transceiver 630: RS-422 transceiver
640: RS-485 transceiver

Claims (5)

An interface mode register set to a value for selecting a line interface of any one of a plurality of transceivers;
A dip switch set to a value of at least one of an on state and an off state; And
And an interface mode control unit generating an interface mode selection value according to at least one of the value of the interface mode register, the value of the dip switch, and the value of the received signal, and controlling each of the plurality of transceivers according to the interface mode selection value. Composed,
The line interface control unit
The value of the interface mode register and the value of the dip switch are determined as an interface mode selection value according to MODE_SELECT among the received signals, and a mode selection signal is generated according to the interface mode selection value,
RS-232, RS-422, RS-485 selection and output signal, characterized in that for generating a mode selection signal for activating any one of the plurality of transceivers and deactivating the remaining transceivers according to the interface mode selection value Automatic controller. delete delete According to claim 1,
The line interface control unit
The plurality of transceivers are on the same board, and according to the interface mode selection value, it is characterized in that it generates a mode selection signal for activating the corresponding transceiver and deactivating the remaining transceivers in one of the plurality of communication modes. , RS-232, RS-422, RS-485 selection and output signal automatic controller. According to claim 4,
The plurality of transceivers
RS-232, RS-422, RS-485 selection and output signal automatic controller, characterized in that one of the RS-232 transceiver, RS-422 transceiver and RS-485 transceiver operates.

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