Serial port single-line bidirectional transceiver circuit

Abstract

The utility model relates to the technical field of transceiver circuits, in particular to a serial port single-line bidirectional transceiver circuit, which comprises a first serial port, a second serial port and a switching module, the switching module comprises a first switching circuit and a second switching circuit which are reversely connected; a receiving line and a transmitting line of the first serial port are connected to the input end of the first switching circuit, and a receiving line and a transmitting line of the second serial port are connected to the input end of the second switching circuit; and the first switching circuit and the second switching circuit are also connected with an input power supply. According to the utility model, the problem that each TX or RX data line has complete TX and RX data transmission functions on the basis of the existing resources under the condition of not increasing peripheral hardware interfaces is solved.

Description

Technical Field

[0001] The utility model relates to the technical field of transceiver circuits, in particular to a serial port single-line bidirectional transceiver circuit. Background Art

[0002] A serial port, also known as a "serial port" or a serial communication interface (often referred to as a COM interface), is an expansion interface that uses serial communication. Serial interfaces transmit data bit by bit sequentially. Their advantages include simple communication lines, enabling bidirectional communication with just a single pair of transmission lines. They can also utilize telephone lines, significantly reducing costs and making them particularly suitable for long-distance communication. However, transmission speeds are relatively slow. Serial communication, in which each bit of a message is transmitted sequentially, is called serial communication. Serial communication is characterized by bit-by-bit transmission, requiring only a single transmission line, and low cost, but also by slow transmission speeds.

[0003] In consumer electronics, most devices communicate with peripherals through serial ports. However, the number of exposed serial ports on devices is limited. If multiple peripherals need to be connected, one or more serial ports need to be added, which is a cumbersome operation and usually requires redesigning the casing or modifying the mold. Utility Model Content

[0004] The utility model provides a serial port single-line bidirectional transceiver circuit, which mainly solves the problem of allowing each TX or RX line to have complete TX and RX data transmission functions based on existing resources without adding peripheral hardware interfaces.

[0005] The utility model proposes a serial port single-line bidirectional transceiver circuit, comprising a first serial port, a second serial port and a switching module; the switching module comprises a first switching circuit and a second switching circuit connected in reverse; the receiving line and the transmitting line of the first serial port are connected to the input end of the first switching circuit, and the receiving line and the transmitting line of the second serial port are connected to the input end of the second switching circuit; the first switching circuit and the second switching circuit are also connected to an input power supply;

[0006] When the transmission line of the first serial port or the transmission line of the second serial port outputs a high level, the first switch circuit and the second switch circuit are turned off; when the transmission line of the first serial port outputs a low level, the first switch circuit and the second switch circuit are partially turned on, the receiving line of the first serial port is a high level, and the receiving line of the second serial port is a low level; when the transmission line of the second serial port outputs a low level, the first switch circuit and the second switch circuit are partially turned on, the receiving line of the second serial port is a high level, and the receiving line of the first serial port is a low level.

[0007] Preferably, the first switch circuit includes a MOS transistor Q1 and a MOS transistor Q3;

[0008] The transmitting line of the first serial port is connected in parallel to the S terminal of the MOS transistor Q1 and to the G terminal of the MOS transistor Q3; the receiving line of the first serial port and the input power supply are connected in parallel to the D terminal of the MOS transistor Q3; the G terminal of the MOS transistor Q1 is connected to the input power supply; the D terminal of the MOS transistor Q1 and the S terminal of the MOS transistor Q3 are connected in parallel and output as the output terminal of the first switching circuit;

[0009] The output end of the first switch circuit is connected to the second switch circuit.

[0010] Preferably, the second switch circuit includes a MOS transistor Q2 and a MOS transistor Q4;

[0011] The transmitting line of the second serial port is connected in parallel to the S terminal of the MOS transistor Q2 and to the G terminal of the MOS transistor Q4; the receiving line of the second serial port and the input power supply are connected in parallel to the D terminal of the MOS transistor Q4; the G terminal of the MOS transistor Q2 is connected to the input power supply; the D terminal of the MOS transistor Q2 and the S terminal of the MOS transistor Q4 are connected in parallel and output as the output terminal of the second switch circuit;

[0012] The output end of the first switch circuit is connected to the output end of the second switch circuit.

[0013] Preferably, it further comprises a resistor, one end of which is connected to the input power supply, and the other end of which is connected to the first switching circuit and / or the second switching circuit.

[0014] Preferably, the first serial port and the second serial port belong to different peripheral devices, and the input power supplies of the first switch circuit and the second switch circuit belong to different peripheral devices.

[0015] Preferably, the transmission line of the first serial port is connected to the input end of the first switch circuit through a first filter module, and the transmission line of the second serial port is connected to the input end of the second switch circuit through a second filter module.

[0016] As can be seen from the above, the application of the technical solution provided by the utility model can achieve the following beneficial effects:

[0017] First, the serial port single-line bidirectional transceiver circuit proposed in the present invention enables the TX or RX data line to have complete TX or RX data transmission functions without adding a new peripheral hardware interface;

[0018] Secondly, the serial port single-line bidirectional transceiver circuit proposed by the present invention is assembled through simple electrical components, has low implementation difficulty, can maintain a high-efficiency communication rate, and realize bidirectional transceiver. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0020] Figure 1 This is a circuit diagram of a serial port single-line bidirectional transceiver circuit in an embodiment of the present utility model. DETAILED DESCRIPTION

[0021] The following will be combined with the accompanying drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without expending creative work are within the scope of protection of the present invention.

[0022] This embodiment solves the problem of enabling each TX or RX data line to have complete TX and RX data transmission functions using existing resources without adding peripheral hardware interfaces.

[0023] This embodiment proposes a serial port single-line bidirectional transceiver circuit, including a first serial port, a second serial port and a switching module; the switching module includes a first switching circuit and a second switching circuit connected in reverse order; the receiving line and the transmitting line of the first serial port are connected to the input end of the first switching circuit, and the receiving line and the transmitting line of the second serial port are connected to the input end of the second switching circuit; the first switching circuit and the second switching circuit are also connected to an input power supply.

[0024] Among them, when the transmission line of the first serial port or the transmission line of the second serial port outputs a high level, the first switch circuit and the second switch circuit are cut off; when the transmission line of the first serial port outputs a low level, the first switch circuit and the second switch circuit are partially turned on, the receiving line of the first serial port is a high level, and the receiving line of the second serial port is a low level; when the transmission line of the second serial port outputs a low level, the first switch circuit and the second switch circuit are partially turned on, the receiving line of the second serial port is a high level, and the receiving line of the first serial port is a low level.

[0025] Preferably, in this embodiment, the first serial port and the second serial port belong to different peripheral devices, and the input power supplies connected to the first switch circuit and the second switch circuit also belong to different peripheral devices. Preferably, but not limited to, the first serial port and the input power supply to the first switch circuit are located at device 1, and the second serial port and the input power supply to the second switch circuit are located at device 2.

[0026] Preferably, in this embodiment, the device 1 end of the first serial port and the device 2 end of the first serial port are in a half-duplex working state.

[0027] In this embodiment, the first switching circuit includes a MOS transistor Q1 and a MOS transistor Q3; the transmitting line of the first serial port is connected in parallel to the S terminal of the MOS transistor Q1 and to the G terminal of the MOS transistor Q3; the receiving line of the first serial port and the input power supply are connected in parallel to the D terminal of the MOS transistor Q3; the G terminal of the MOS transistor Q1 is connected to the input power supply; the D terminal of the MOS transistor Q1 and the S terminal of the MOS transistor Q3 are connected in parallel to form the output terminal of the first switching circuit; and the output terminal of the first switching circuit is connected to the second switching circuit.

[0028] The second switching circuit includes a MOS transistor Q2 and a MOS transistor Q4; the transmitting line of the second serial port is connected in parallel to the S terminal of the MOS transistor Q2 and to the G terminal of the MOS transistor Q4; the receiving line of the second serial port and the input power supply are connected in parallel to the D terminal of the MOS transistor Q4; the G terminal of the MOS transistor Q2 is connected to the input power supply; the D terminal of the MOS transistor Q2 and the S terminal of the MOS transistor Q4 are connected in parallel to output as the output terminal of the second switching circuit; the output terminal of the first switching circuit is connected to the output terminal of the second switching circuit.

[0029] It also includes a resistor with one end connected to the input power supply and the other end connected to the first switch circuit and / or the second switch circuit.

[0030] In this embodiment, when the transmitter TX1 of device 1 transmits a high level, the transmitter TX2 of device 2 defaults to a high level, turning off MOS transistors Q1 and Q2. Due to the influence of the MOS transistor parasitic diodes, the third pins of MOS transistors Q1 and Q2 are also high, and MOS transistors Q3 and Q4 are almost in the off state. The receiver RX1 of the first serial port is pulled up to the first serial port input power supply VCC1 through resistor R3, and the receiver RX2 of the second serial port is pulled up to the second serial port input power supply VCC2 through resistor R4. Therefore, the receivers RX1 and RX2 of the first and second serial ports are both high.

[0031] Furthermore, when transmitter TX1 of device 1 transmits a low level, MOS transistor Q1 is on, and pins 3 and 2 of MOS transistor Q1 are connected, so pin 3 is low. MOS transistor Q3 is off, and receiver RX1 is pulled up to the input power supply VCC1 via R3. At this point, receiver RX1 is high, so regardless of whether transmitter TX1 is sending data, receiver RX1 remains high. Transmitter TX2 of device 2 defaults to a high level, and MOS transistor Q2 is off. Because pins 2 and 3 of MOS transistor Q4 are connected to pin 3 of MOS transistor Q1, both are low, MOS transistor Q4 is on, and receiver RX2 is low. Therefore, when transmitter TX1 sends data, only receiver RX2 can receive it.

[0032] Furthermore, when transmitter TX2 sends a high level, MOS transistor Q2 is turned off. Transmitter TX1 defaults to a high level, and MOS transistor Q1 is also turned off. However, due to the influence of the MOS transistor parasitic diodes, pins 3 of MOS transistors Q1 and Q2 are also high, and MOS transistors Q3 and Q4 are almost in the off state. Since receiver RX1 is pulled up to input power supply VCC1 through resistor R3, and receiver RX2 is pulled up to input power supply VCC2 through resistor R4, both receivers RX1 and RX2 are high.

[0033] Furthermore, when transmitter TX2 sends a low signal, MOS transistor Q2 turns on, connecting pins 3 and 2 of MOS transistor Q2, both at a low level. MOS transistor Q4 is turned off. Since receiver RX2 is pulled up to the input power supply VCC2 via R4, RX2 is always at a high level. Therefore, regardless of the data transmitted by transmitter TX2, RX2 remains at a high level. Transmitter TX1 defaults to a high level, turning off MOS transistor Q1. However, pin 2 of MOS transistor Q3 is at a low level, turning on MOS transistor Q3, and receiver RX1 remains at a low level. Therefore, data sent by transmitter TX2 can only be received by receiver RX1.

[0034] Preferably, in this embodiment, the MOS transistors Q1 , Q2 , Q3 and Q4 are all NMOS transistors.

[0035] Preferably, in order to ensure the stability and accuracy of the transmission signal of the first serial port and the transmission information of the second serial port, a first filtering module and a second filtering module are respectively provided in this embodiment.

[0036] As can be seen from the above, this embodiment proposes a serial port single-line bidirectional transceiver circuit, which can realize the complete TX and RX data transmission functions by implementing the TX data line or the RX data line through the circuit, thereby avoiding the problem of insufficient serial ports when connecting the device to the peripheral device, which requires modification or redesign.

[0037] The above-described embodiments do not constitute a limitation on the scope of protection of this technical solution. Any modifications, equivalent replacements, and improvements made within the spirit and principles of the above-described embodiments shall be included in the scope of protection of this technical solution.

Claims

1. A serial port single-line bidirectional transceiver circuit, characterized in that: The device comprises a first serial port, a second serial port, and a switching module; the switching module comprises a first switching circuit and a second switching circuit connected in reverse; the receiving line and the transmitting line of the first serial port are connected to the input end of the first switching circuit, and the receiving line and the transmitting line of the second serial port are connected to the input end of the second switching circuit; the first switching circuit and the second switching circuit are also connected to an input power supply; When the transmission line of the first serial port or the transmission line of the second serial port outputs a high level, the first switch circuit and the second switch circuit are turned off; when the transmission line of the first serial port outputs a low level, the first switch circuit and the second switch circuit are partially turned on, the receiving line of the first serial port is a high level, and the receiving line of the second serial port is a low level; when the transmission line of the second serial port outputs a low level, the first switch circuit and the second switch circuit are partially turned on, the receiving line of the second serial port is a high level, and the receiving line of the first serial port is a low level.

2. The serial port single-line bidirectional transceiver circuit according to claim 1, characterized in that: The first switch circuit includes a MOS transistor Q1 and a MOS transistor Q3; The transmitting line of the first serial port is connected in parallel to the S terminal of the MOS transistor Q1 and to the G terminal of the MOS transistor Q3; the receiving line of the first serial port and the input power supply are connected in parallel to the D terminal of the MOS transistor Q3; the G terminal of the MOS transistor Q1 is connected to the input power supply; the D terminal of the MOS transistor Q1 and the S terminal of the MOS transistor Q3 are connected in parallel and output as the output terminal of the first switching circuit; The output end of the first switch circuit is connected to the second switch circuit.

3. The serial port single-line bidirectional transceiver circuit according to claim 2, characterized in that: The second switch circuit includes a MOS transistor Q2 and a MOS transistor Q4; The transmitting line of the second serial port is connected in parallel to the S terminal of the MOS transistor Q2 and to the G terminal of the MOS transistor Q4; the receiving line of the second serial port and the input power supply are connected in parallel to the D terminal of the MOS transistor Q4; the G terminal of the MOS transistor Q2 is connected to the input power supply; the D terminal of the MOS transistor Q2 and the S terminal of the MOS transistor Q4 are connected in parallel and output as the output terminal of the second switch circuit; The output end of the first switch circuit is connected to the output end of the second switch circuit.

4. A serial port single-line bidirectional transceiver circuit according to claim 3, characterized in that: Also includes: A resistor, one end of which is connected to the input power supply, and the other end of which is connected to the first switching circuit and / or the second switching circuit.

5. The serial port single-line bidirectional transceiver circuit according to claim 4, characterized in that: The first serial port and the second serial port belong to different peripheral devices, and the input power supplies of the first switch circuit and the second switch circuit belong to different peripheral devices.

6. The serial port single-line bidirectional transceiver circuit according to any one of claims 1 to 5, characterized in that: The transmission line of the first serial port is connected to the input end of the first switch circuit through a first filter module, and the transmission line of the second serial port is connected to the input end of the second switch circuit through a second filter module.

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