CN220798358U - Serial port communication circuit and mainboard based on HDMI interface - Google Patents
Serial port communication circuit and mainboard based on HDMI interface Download PDFInfo
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- CN220798358U CN220798358U CN202322379735.7U CN202322379735U CN220798358U CN 220798358 U CN220798358 U CN 220798358U CN 202322379735 U CN202322379735 U CN 202322379735U CN 220798358 U CN220798358 U CN 220798358U
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Abstract
The utility model discloses a serial port communication circuit and a main board based on an HDMI interface, wherein the serial port communication circuit based on the HDMI interface comprises: the device comprises a first conversion unit, a second conversion unit and a control unit, wherein the first end of the first conversion unit is connected with a serial port transmitting end, and the second end of the first conversion unit is connected with a data end of an HDMI (high-definition multimedia interface); the first end of the second conversion unit is connected with the serial port receiving end, the second end of the second conversion unit is connected with the clock end of the HDMI, the third end of the first conversion unit is connected with the third end of the second conversion unit and is provided with a first node, and the first node is connected with a preset constant voltage source; the first end of the control unit is connected with the first node, the second end of the control unit is connected with a connection signal end of the HDMI, and the third end of the control unit is grounded. Therefore, the utility model can realize serial communication through the HDMI interface without interfering the normal use of the HDMI interface, realize multiplexing the HDMI interface, reduce the serial setting number of the equipment and improve the integration level.
Description
Technical Field
The utility model relates to the technical field of serial port communication, in particular to a serial port communication circuit and a main board based on an HDMI (High Definition Multimedia Interface ) interface.
Background
At present, the mainboards such as a computer, a display and the like all require an external debugging interface to be reserved, thereby facilitating the automatic production of factories and providing functions such as after-sales upgrade and the like.
In the related art, the external debugging serial port interface is designed to perform compatible communication through a VGA (Video Graphics Array ) interface, and the 12 and 15 pins in the definition of the VGA interface are multiplexed to serve as a transmitting and receiving network of the serial port to perform signal transmission, but the VGA interfaces of a plurality of computers and displays are cancelled, so that the function of searching for a commonly used interface to realize serial port communication is required, otherwise, a port is required to be independently arranged to realize serial port communication, and the integration level of devices such as computers and displays is greatly reduced.
Disclosure of Invention
The present utility model aims to solve at least one of the technical problems in the related art to some extent. Therefore, an object of the present utility model is to provide a serial communication circuit based on an HDMI interface, which can realize serial communication through the HDMI interface without interfering with normal use of the HDMI interface, realize multiplexing of the HDMI interface, reduce serial setting number of devices, and improve integration level.
A second object of the present utility model is to provide a motherboard.
To achieve the above object, a first aspect of the present utility model provides a serial port communication circuit based on HDMI interface, the circuit comprising: the first end of the first conversion unit is connected with the serial port transmitting end, and the second end of the first conversion unit is connected with the data end of the HDMI; the first end of the second conversion unit is connected with the serial port receiving end, the second end of the second conversion unit is connected with the clock end of the HDMI, the third end of the first conversion unit is connected with the third end of the second conversion unit and is provided with a first node, and the first node is connected with a preset constant voltage source; the first end of the control unit is connected with the first node, the second end of the control unit is connected with the connection signal end of the HDMI, and the third end of the control unit is grounded.
The serial port communication circuit based on the HDMI interface in the embodiment comprises a first conversion unit, a second conversion unit and a control unit, wherein the control unit is respectively connected with the first conversion unit and the second conversion unit through a first node, and then can send control signals to the first conversion unit and the second conversion unit according to signals received by a connection signal end of the HDMI interface so as to control the first conversion unit and the second conversion unit, so that serial port communication can be realized through the HDMI interface under the condition that normal use of the HDMI interface is not interfered, multiplexing of the HDMI interface is realized, the serial port setting number of equipment is reduced, and the integration level is improved.
In some embodiments of the present utility model, a first resistor is disposed between the first node and the preset constant voltage source.
In some embodiments of the present utility model, the resistance of the first resistor is smaller than a first preset resistance.
In some embodiments of the utility model, the first conversion unit comprises: the first end of the first switching tube is used as the first end of the first conversion unit, the second end of the first switching tube is used as the second end of the first conversion unit, and the control end of the first switching tube is used as the third end of the first conversion unit.
In some embodiments of the utility model, the first conversion unit further comprises: and one end of the second resistor is connected with the control end of the first switching tube, and the other end of the second resistor is used as a third end of the first conversion unit.
In some embodiments of the present utility model, the first switching tube is an NMOS (N-Metal-Oxide-Semiconductor) tube, a first end of the first switching tube is a drain electrode of the NMOS tube, a second end of the first switching tube is a source electrode of the NMOS tube, and a control end of the first switching tube is a gate electrode of the NMOS tube.
In some embodiments of the utility model, the second conversion unit comprises: the first end of the second switching tube is used as the first end of the second conversion unit, the second end of the second switching tube is used as the second end of the second conversion unit, and the control end of the second switching tube is used as the third end of the second conversion unit.
In some embodiments of the utility model, the second conversion unit further comprises: and one end of the third resistor is connected with the control end of the second switching tube, and the other end of the third resistor is used as the third end of the second conversion unit.
In some embodiments of the present utility model, the second switching tube is an NMOS tube, a first end of the second switching tube is a drain electrode of the NMOS tube, a second end of the second switching tube is a source electrode of the NMOS tube, and a control end of the second switching tube is a gate electrode of the NMOS tube.
In some embodiments of the utility model, the control unit comprises: and the first end of the third switching tube is used as the first end of the control unit, the second end of the third switching tube is used as the third end of the control unit and is grounded, and the control end of the third switching tube is connected with the connection signal end of the HDMI interface.
In some embodiments of the utility model, the control unit further comprises: one end of the fourth resistor is directly connected with the connecting signal end of the HDMI, and the other end of the fourth resistor is connected with the control end of the third switching tube and is provided with a second node; and one end of the fifth resistor is connected with the second node, and the other end of the fifth resistor is grounded as a third end of the control unit.
In some embodiments of the present utility model, the third switching tube is an NPN triode, the first end of the third switching tube is a collector of the NPN triode, the second end of the third switching tube is an emitter of the NPN triode, and the control end of the third switching tube is a base of the NPN triode.
To achieve the above objective, an embodiment of a second aspect of the present utility model provides a motherboard, which includes the serial communication circuit based on the HDMI interface in any of the above embodiments.
The mainboard in this embodiment can realize serial communication through the HDMI interface under the condition that the HDMI interface is not interfered with normal use of the HDMI interface through the serial communication circuit based on the HDMI interface in the above embodiment, realize multiplexing the HDMI interface, reduce serial setting quantity of equipment, and improve integration level.
Additional aspects and advantages of the utility model will be set forth in part in the description which follows and, in part, will be obvious from the description, or may be learned by practice of the utility model.
Drawings
FIG. 1 is a schematic diagram of a serial communication circuit based on an HDMI interface in accordance with one embodiment of the present utility model;
fig. 2 is a functional schematic diagram of each pin of the HDMI socket;
fig. 3 is a diagram showing a signal comparison between a serial port transmitting end and a data end of an HDMI interface according to an embodiment of the present utility model;
FIG. 4 is a diagram of signal comparison between a serial port receiving end and a clock end of an HDMI interface in accordance with one embodiment of the present utility model;
fig. 5 is a block diagram of a motherboard according to an embodiment of the present utility model.
Detailed Description
Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative and intended to explain the present utility model and should not be construed as limiting the utility model.
The serial communication circuit and the main board based on the HDMI interface according to the embodiment of the present utility model are described below with reference to the accompanying drawings.
HDMI is a full digital video and sound transmission interface, can transmit uncompressed audio and video signals, and can be compatible with the external debugging and production after-sales requirements of most of electronic products such as desktop computers, notebook computers, displays and projectors at present, so that the complex process of dismantling equipment shells or additionally operating equipment mainboards is avoided, and under the situation that high-definition audio and video media interaction is increasingly popular, the HDMI interface has become the standard of media platforms such as desktop computers, notebook computers and displays. Under the condition that VGA interfaces are gradually eliminated and HDMI interfaces are gradually popularized, the transition of the functions of the VGA interfaces to the HDMI interfaces is a trend, but the function of the VGA interfaces can be realized by ensuring that the HDMI interfaces are not influenced under the condition that the normal work of the HDMI interfaces is not influenced, proper circuit design is needed.
Fig. 1 is a schematic diagram of a serial communication circuit based on an HDMI interface according to an embodiment of the present utility model.
Referring to fig. 1, the serial communication circuit 100 based on the HDMI interface in the present embodiment includes a first conversion unit 11, a second conversion unit 12, and a control unit 13, where a first end of the first conversion unit 11 is connected to a serial port transmitting end uart_tx (Universal Asynchronous Receiver/transceiver), a second end of the first conversion unit 11 is connected to a data end hdmi_sda of the HDMI interface, a first end of the second conversion unit 12 is connected to a serial port receiving end uart_rx, a second end of the second conversion unit 12 is connected to a clock end hdmi_scl of the HDMI interface, a third end of the first conversion unit 11 and a third end of the second conversion unit 12 are connected and have a first node P1, and the first node P1 is connected to a preset constant voltage source +5v_standby, a first end of the control unit 13 is connected to the first node P1, a second end of the control unit 13 is connected to a connection signal end hdmi_5v of the HDMI interface, and a third end of the control unit 13 is grounded.
Specifically, in this embodiment, the first conversion unit 11 is connected to the data end hdmi_sda and the serial port transmitting end uart_tx of the HDMI interface, the second conversion unit 12 is connected to the clock end hdmi_scl and the serial port receiving end uart_rx of the HDMI interface, and the first conversion unit 11 and the second conversion unit 12 are further connected to the control unit 13 after being connected through the first node P1, the control unit 13 is connected to the connection signal end hdmi_5v of the HDMI interface and the preset constant voltage source +5v_standby, and when the HDMI interface is normally connected to the HDMI socket, the connection signal end hdmi_5v of the HDMI interface can generate a voltage signal, so that the control unit 13 can control the first conversion unit 11 and the second conversion unit 12 according to the voltage signal, and if the HDMI interface is connected to the serial port communication socket, the connection signal end hdmi_5v of the HDMI interface cannot generate the voltage signal, so that the first conversion unit 11 and the second conversion unit 12 are still controlled by the preset constant voltage source +5v_standby to normally perform serial port communication. Obviously, the serial communication circuit 100 in this embodiment can automatically switch according to whether the HDMI interface is connected to the HDMI socket, so that serial communication can be realized through the HDMI interface without affecting the normal operation of the HDMI interface.
Referring to fig. 2 for a detailed description, fig. 2 is a functional schematic diagram of each pin of the HDMI socket, where the 15 th pin and the 16 th pin are respectively a clock end hdmi_scl of the HDMI interface and a data end hdmi_sda of the HDMI interface, and are respectively connected to the clock end hdmi_scl of the HDMI interface and the data end hdmi_sda of the HDMI interface in fig. 1, when the HDMI interface is normally connected to the HDMI socket, the HDMI is normally operated, and the internal master control chip can send related signals to the outside through the clock end hdmi_scl of the HDMI interface and the data end hdmi_sda of the HDMI interface to maintain a multimedia high-definition screen. When the serial port regulating equipment is connected to the HDMI, the internal main control chip can communicate with the serial port regulating equipment through the serial port transmitting end UART_TX and the serial port receiving end UART_RX, so that functions of debugging, upgrading and the like are completed. It will be appreciated that the function of the other pins in fig. 2 is not limited in detail, and may be set according to the relevant limitation.
In one embodiment of the present utility model, a first resistor R1 is disposed between the first node P1 and the preset constant voltage source +5v_standby, and the resistance value of the first resistor R1 is smaller than a first preset resistance value.
Specifically, referring to fig. 1, a first resistor R1 is further provided between the first node P1 and the preset constant voltage source +5v_standby, and the first resistor R1 is capable of performing a current limiting process after the control unit 13 controls the first and second switching units 11 and 12 to be turned off. In a specific embodiment, one end of the first resistor R1 is connected to a preset constant voltage source +5v_standby, and the other end of the first resistor R1 is grounded through the control unit 13, and the power consumption generated by the circuit in this embodiment when the first and second converting units 11 and 12 are turned off is according to the formula p=u 2 And R is calculated, wherein R can be expressed as the resistance value of the first resistor R1, U is the voltage value of a preset constant voltage source +5V_standby connected with one end of the first resistor R1, and the resistance value of the first resistor R1 can be set smaller than a first preset resistance value under the condition of combining function consumption and serial port communication quality. Alternatively, the first preset resistance in this embodiment may be 47K ohms, and the voltage value of the preset constant voltage source +5v_standby may be 5 volts.
In some embodiments of the present utility model, the first conversion unit 11 includes a first switching tube Q1 and a second resistor R2, wherein a first end of the first switching tube Q1 is used as a first end of the first conversion unit 11, and a second end of the first switching tube Q1 is used as a second end of the first conversion unit 11; one end of the second resistor R2 is connected to the control end of the first switching tube Q1, and the other end of the second resistor R2 is used as the third end of the first conversion unit 11. The first switching tube Q1 is an NMOS tube, the first end of the first switching tube Q1 is the drain electrode of the NMOS tube, the second end of the first switching tube Q1 is the source electrode of the NMOS tube, and the control end of the first switching tube Q1 is the grid electrode of the NMOS tube.
Specifically, in this embodiment, the first converting unit 11 includes a first switching tube Q1 and a second resistor R2, the first switching tube Q1 may be an NMOS tube, the drain of the NMOS tube may be used as the first end of the first converting unit, that is, the drain of the NMOS tube is connected to the serial port transmitting end uart_tx, the source of the NMOS tube may be used as the second end of the first converting unit 11, that is, the source of the NMOS tube is connected to the data end hdmi_sda of the HDMI interface, the gate of the NMOS tube is connected to one end of the second resistor R2, the other end of the second resistor R2 is used as the third end of the first converting unit 11, and the other end of the second resistor R2 is connected to the first node P1.
In this embodiment, since the first node P1 is connected to the preset constant voltage source +5v_standby through the first resistor R1, if the control unit 13 is in an off state so that the first node P1 is not grounded, the second resistor R2 can divide the voltage of the preset constant voltage source +5v_standby, and can provide a high level to the control terminal of the first switching tube Q1 to turn on the first switching tube Q1; and if the control unit 13 is in a closed state so that the first node P1 is grounded, the voltage division function cannot be implemented by the second resistor R2 at this time, so that the control terminal of the first switching tube Q1 is at a low level, and the first switching tube Q1 is turned off. It can be understood that, when the first switching tube Q1 is turned on, the internal main control chip can send information to the data end hdmi_sda of the HDMI interface through the serial port transmitting end uart_tx, so when the HDMI interface is connected to the socket for serial port communication, a corresponding signal can be automatically provided to the control unit 13 to make the control unit 13 in an off state; under the condition that the first switching tube Q1 is turned off, the internal main control chip cannot send information to the data end hdmi_sda of the HDMI interface through the serial port transmitting end uart_tx, so when the HDMI interface is connected to the HDMI socket, a corresponding signal can be automatically provided to the control unit 13 to make the control unit 13 in a closed state.
In some embodiments of the present utility model, the second conversion unit 12 includes a second switching tube Q2 and a third resistor R3, wherein a first end of the second switching tube Q2 is used as a first end of the second conversion unit 12, and a second end of the second switching tube Q2 is used as a second end of the second conversion unit 12; one end of the third resistor R3 is connected to the control end of the second switching tube Q2, and the other end of the third resistor R3 is used as the third end of the second conversion unit 12. The second switching tube Q2 is an NMOS tube, the first end of the second switching tube Q2 is the drain electrode of the NMOS tube, the second end of the second switching tube Q2 is the source electrode of the NMOS tube, and the control end of the second switching tube Q2 is the grid electrode of the NMOS tube.
Specifically, in this embodiment, the second converting unit 12 includes a second switching tube Q2 and a third resistor R3, the second switching tube Q2 may be an NMOS tube, the drain of the NMOS tube may be used as the first end of the second converting unit, that is, connected to the serial port receiving end uart_rx through the drain of the NMOS tube, the source of the NMOS tube may be used as the second end of the second converting unit 12, that is, connected to the clock end hdmi_scl of the HDMI interface through the source of the NMOS tube, the gate of the NMOS tube is connected to one end of the third resistor R3, the other end of the third resistor R3 is used as the third end of the second converting unit 12, and the other end of the third resistor R3 is connected to the first node P1.
In this embodiment, since the first node P1 is connected to the preset constant voltage source +5v_standby through the third resistor R3, if the control unit 13 is in an off state so that the first node P1 is not grounded, the third resistor R3 can divide the preset constant voltage source +5v_standby, and can provide a high level to the control terminal of the second switching tube Q2 so as to turn on the second switching tube Q2; and if the control unit 13 is in a closed state so that the first node P1 is grounded, the voltage dividing function cannot be implemented by the third resistor R3 at this time, so that the control terminal of the second switching tube Q2 is at a low level, and the second switching tube Q2 is turned off. It can be understood that, when the second switching tube Q2 is turned on, the internal master control chip can send information to the clock end hdmi_scl end of the HDMI interface through the serial port receiving end uart_rx, so when the HDMI interface is connected to the socket for serial port communication, a corresponding signal can be automatically provided to the control unit 13 to make the control unit 13 in an off state; under the condition that the first switching tube Q1 is turned off, the internal master control chip cannot send information to the clock end hdmi_scl of the HDMI through the serial port receiving end uart_rx, so when the HDMI is connected to the HDMI socket, a corresponding signal can be automatically provided to the control unit 13 to make the control unit 13 in a closed state.
In a specific embodiment, the first switching tube Q1 and the second switching tube Q2 are both designed with body diodes, as shown in fig. 1, when the HDMI is normally connected to the HDMI socket, due to the body diodes, the serial port transmitting end uart_tx at the cathode of the body diode cannot transmit signals to the data end hdmi_sda at the HDMI interface of the anode of the body diode, and the serial port receiving end uart_rx at the cathode of the body diode cannot transmit signals to the clock end hdmi_scl at the HDMI interface of the anode of the body diode, so that when the HDMI interface is normally connected to the HDMI signal, interference of communication signals is avoided, and the NMOS tube is protected to a certain extent.
In some embodiments of the utility model, the control unit 13 comprises: the first end of the third switching tube is used as the first end of the control unit 13, and the second end of the third switching tube is grounded; one end of the fourth resistor R4 is connected with a connection signal end HDMI_5V of the HDMI interface, and the other end of the fourth resistor R4 is connected with a control end of the third switch tube and provided with a second node P2; one end of the fifth resistor R5 is connected to the second node P2, and the other end of the fifth resistor R5 serves as a third end of the control unit 13. The third switching tube is an NPN triode, the first end of the third switching tube is a collector electrode of the NPN triode, the second end of the third switching tube is an emitter electrode of the NPN triode, and the control end of the third switching tube is a base electrode of the NPN triode.
Specifically, the third switching tube in the control unit 13 may be an NPN transistor, where an emitter of the NPN transistor is grounded, and when a base of the NPN transistor is at a high level, the NPN transistor is in an on state, so that the first node P1 can be grounded through the third switching tube, so that a control end of the first switching tube Q1 and a control end of the second switching tube Q2 are in a low level state and are in an off state, and the serial port receiving end uart_rx and the serial port transmitting end uart_tx cannot transmit information to the clock end hdmi_scl of the HDMI interface and the data end hdmi_sda of the HDMI interface. Therefore, when the HDMI interface is connected to the HDMI socket, the base of the third switching tube needs to be at a high level, in this embodiment, the connection signal end hdmi_5v of the HDMI interface is connected to one end of the fourth resistor R4, and when the HDMI interface is connected to the HDMI socket, the connection signal end hdmi_5v of the HDMI interface will automatically generate a voltage, which may be 5V, so that the control end of the third switching tube can be controlled to be at a high level state after voltage division by the fourth resistor R4. If the HDMI interface is not connected to the HDMI socket, the connection signal end hdmi_5v of the HDMI interface connected to one end of the fourth resistor R4 will not generate a voltage, so that the third switching tube is in an off state, and the first node P1 is still in a high level state due to the preset constant voltage source +5v_standby, so that the first switching tube Q1 and the second switching tube Q2 are in an on state, and therefore the serial port receiving end uart_rx and the serial port transmitting end uart_tx can transmit information to the clock end hdmi_scl of the HDMI interface and the data end hdmi_sda of the HDMI interface, and further communicate with a debugging device externally connected to the clock end hdmi_scl and the data end hdmi_sda.
In a specific embodiment, the voltage value after the voltage division of the fourth resistor R4 and the fifth resistor R5 is required to be greater than the on threshold of the third switch tube, in general, the base on threshold of the NPN triode is greater than 0.6 v, and after the HDMI interface is connected to the HDMI socket, the voltage generated at the receiving signal end of the HDMI interface needs to be greater than 0.6 v after the voltage division of the fourth resistor R4 and the fifth resistor R5, so that the fourth resistor R4 and the fifth resistor R5 can be screened according to the condition.
It should be noted that, in a specific embodiment, as shown in fig. 2, a sixth resistor R6 and an eighth resistor R8 are disposed on a 15 th pin of the HDMI socket, and a seventh resistor R7 and a ninth resistor R9 are disposed on a 16 th pin of the HDMI socket, where the other ends of the sixth resistor R6 and the seventh resistor R7 are connected to a receiving signal end of the HDMI interface.
As shown in fig. 3, by comparing the signal of the uart_tx at the serial port transmitting end with the signal of the hdmi_sda at the data end of the HDMI interface in the process of performing serial port communication debugging by using the HDMI interface, the serial port communication circuit 100 can receive the same signal as the signal of the uart_tx at the serial port transmitting end from the data end of the HDMI interface, so that the serial port communication circuit 100 does not change the serial port communication signal and can satisfy normal debugging by the serial port communication signal. The upper gray signal waveform is the signal of the serial port transmitting end uart_tx, and the lower black signal waveform is the signal of the data end hdmi_sda of the HDMI interface.
As shown in fig. 4, by comparing the signal of the uart_rx at the serial port receiving end with the signal of the hdmi_scl at the clock end of the HDMI interface in the process of using the HDMI interface to perform serial port communication debugging, the serial port communication circuit 100 can receive the same signal as the signal of the uart_rx at the serial port receiving end from the hdmi_scl at the clock end of the HDMI interface, so that the serial port communication circuit 100 does not change the serial port communication signal and can satisfy normal debugging through the serial port communication signal. The upper gray signal waveform is the signal of the serial port receiving end uart_rx, and the lower black signal waveform is the signal of the clock end hdmi_scl of the HDMI interface.
In summary, the serial port communication circuit 100 based on the HDMI in the embodiment of the present utility model can realize serial port communication through the HDMI without interfering with normal use of the HDMI, so as to realize multiplexing of the HDMI, reduce the serial port setting number of the device, and improve the integration level.
Fig. 5 is a block diagram of a motherboard according to an embodiment of the present utility model.
As shown in fig. 5, the present utility model proposes a motherboard 1000, where the motherboard 1000 includes the serial communication circuit 100 based on the HDMI interface in the above embodiment.
The motherboard 1000 in this embodiment can realize serial communication through the HDMI interface under the condition that the normal use of the HDMI interface is not interfered by the serial communication circuit 100 based on the HDMI interface in the above embodiment, so as to realize multiplexing of the HDMI interface, reduce the serial setting number of devices, and improve the integration level.
In addition, other configurations and functions of the motherboard according to the embodiments of the present utility model are known to those skilled in the art, and are not described herein for redundancy reduction.
In the description of the present specification, a description referring to terms "one embodiment," "some embodiments," "examples," "specific examples," or "some examples," etc., means that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.
Furthermore, the terms "first," "second," and the like, as used in embodiments of the present utility model, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or as implying any particular number of features in the present embodiment. Thus, a feature of an embodiment of the utility model that is defined by terms such as "first," "second," etc., may explicitly or implicitly indicate that at least one such feature is included in the embodiment. In the description of the present utility model, the word "plurality" means at least two or more, for example, two, three, four, etc., unless explicitly defined otherwise in the embodiments.
In the present utility model, unless explicitly stated or limited otherwise in the examples, the terms "mounted," "connected," and "fixed" as used in the examples should be interpreted broadly, e.g., the connection may be a fixed connection, may be a removable connection, or may be integral, and it may be understood that the connection may also be a mechanical connection, an electrical connection, etc.; of course, it may be directly connected, or indirectly connected through an intermediate medium, or may be in communication with each other, or in interaction with each other. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to specific embodiments.
While embodiments of the present utility model have been shown and described above, it will be understood that the above embodiments are illustrative and not to be construed as limiting the utility model, and that variations, modifications, alternatives and variations may be made to the above embodiments by one of ordinary skill in the art within the scope of the utility model.
Claims (13)
1. A serial port communication circuit based on an HDMI interface, the circuit comprising:
the first end of the first conversion unit is connected with the serial port transmitting end, and the second end of the first conversion unit is connected with the data end of the HDMI;
the first end of the second conversion unit is connected with the serial port receiving end, the second end of the second conversion unit is connected with the clock end of the HDMI, the third end of the first conversion unit is connected with the third end of the second conversion unit and is provided with a first node, and the first node is connected with a preset constant voltage source;
the first end of the control unit is connected with the first node, the second end of the control unit is connected with the connection signal end of the HDMI, and the third end of the control unit is grounded.
2. The serial port communication circuit of claim 1, wherein a first resistor is provided between the first node and the predetermined constant voltage source.
3. The serial communication circuit of claim 2, wherein the first resistor has a resistance less than a first predetermined resistance.
4. The serial communication circuit of claim 1, wherein the first conversion unit comprises:
the first end of the first switching tube is used as the first end of the first conversion unit, the second end of the first switching tube is used as the second end of the first conversion unit, and the control end of the first switching tube is used as the third end of the first conversion unit.
5. The serial communication circuit of claim 4, wherein the first conversion unit further comprises:
and one end of the second resistor is connected with the control end of the first switching tube, and the other end of the second resistor is used as a third end of the first conversion unit.
6. The serial port communication circuit of claim 4 or 5, wherein the first switching tube is an NMOS tube, a first end of the first switching tube is a drain electrode of the NMOS tube, a second end of the first switching tube is a source electrode of the NMOS tube, and a control end of the first switching tube is a gate electrode of the NMOS tube.
7. The serial communication circuit of claim 1, wherein the second conversion unit comprises:
the first end of the second switching tube is used as the first end of the second conversion unit, the second end of the second switching tube is used as the second end of the second conversion unit, and the control end of the second switching tube is used as the third end of the second conversion unit.
8. The serial communication circuit of claim 7, wherein the second conversion unit further comprises:
and one end of the third resistor is connected with the control end of the second switching tube, and the other end of the third resistor is used as the third end of the second conversion unit.
9. The serial port communication circuit according to claim 7 or 8, wherein the second switching tube is an NMOS tube, a first end of the second switching tube is a drain electrode of the NMOS tube, a second end of the second switching tube is a source electrode of the NMOS tube, and a control end of the second switching tube is a gate electrode of the NMOS tube.
10. The serial communication circuit of claim 1, wherein the control unit comprises:
and the first end of the third switching tube is used as the first end of the control unit, the second end of the third switching tube is used as the third end of the control unit and is grounded, and the control end of the third switching tube is connected with the connection signal end of the HDMI interface.
11. The serial communication circuit of claim 10, wherein the control unit comprises:
one end of the fourth resistor is directly connected with the connecting signal end of the HDMI, and the other end of the fourth resistor is connected with the control end of the third switching tube and is provided with a second node;
and one end of the fifth resistor is connected with the second node, and the other end of the fifth resistor is grounded as a third end of the control unit.
12. The serial port communication circuit according to claim 10 or 11, wherein the third switching tube is an NPN triode, the first end of the third switching tube is a collector of the NPN triode, the second end of the third switching tube is an emitter of the NPN triode, and the control end of the third switching tube is a base of the NPN triode.
13. A motherboard comprising the HDMI-based serial communication circuit of any one of claims 1-12.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322379735.7U CN220798358U (en) | 2023-08-31 | 2023-08-31 | Serial port communication circuit and mainboard based on HDMI interface |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202322379735.7U CN220798358U (en) | 2023-08-31 | 2023-08-31 | Serial port communication circuit and mainboard based on HDMI interface |
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| CN220798358U true CN220798358U (en) | 2024-04-16 |
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| CN202322379735.7U Active CN220798358U (en) | 2023-08-31 | 2023-08-31 | Serial port communication circuit and mainboard based on HDMI interface |
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