Switching circuit for realizing HDMI RX and URAT debugging based on refitted HDMI line

Abstract

The utility model discloses a switching circuit for realizing HDMI RX and URAT debugging based on a refitted HDMI line. The switching circuit comprises a triode switching circuit and an HDMI refitted circuit, according to the switching circuit provided by the utility model, through refitting the HDMI circuit, debugging of a UART serial port and viewing of logcat information can be realized on complete machine equipment with an HDMI IN interface without disassembling and assembling a product or damaging the product. The switching circuit provided by the utility model realizes serial port communication of the HDMI IN interface based on the modified serial port line. The switching circuit provided by the utility model realizes coexistence of HDMI IN and UART functions and hardware switching.

Description

Technical Field

[0001] The utility model relates to a debugging circuit, in particular to a switching circuit for realizing HDMI RX and URAT debugging based on a modified HDMI line. Background Art

[0002] In the prior art, the circuit involved in UART debugging is to implement UART debugging by soldering DuPont wires to test points or reserving DuPont wire male sockets on the mainboard.

[0003] The existing UART debugging interface requires a dedicated test point or DuPont line interface on the motherboard, which makes it inconvenient to use the UART interface for debugging when assembling the whole machine.

[0004] In view of this, it is necessary to improve the circuits involved in UART debugging in the prior art. Utility Model Content

[0005] In view of the deficiencies in the prior art, the technical problem to be solved by the present invention is to provide a switching circuit for realizing HDMI RX and URAT debugging based on a modified HDMI cable. The purpose of designing the switching circuit is to reduce costs.

[0006] In order to solve the above technical problems, the present invention is implemented through the following solutions: the present invention provides a switching circuit for realizing HDMI RX and URAT debugging based on a modified HDMI cable, comprising a triode switching circuit and an HDMI modification circuit;

[0007] The triode switching circuit comprises:

[0008] NPN transistor Q4505, the collector of the NPN transistor Q4505 is connected to the RX circuit, and the emitter of the NPN transistor Q4505 is connected to the HDMI_RXDDC_SCL_PORT circuit;

[0009] The resistor R9259 has a second end connected to the base of the NPN transistor Q4505;

[0010] A resistor R9258, having a first end connected to the VCC5V0 power supply and a second end connected to the first end of the resistor R9259;

[0011] a resistor R9260, a first end of which is connected to the first end of the resistor R9259;

[0012] An NPN transistor Q4506, wherein the base of the NPN transistor Q4506 is connected to the second end of the resistor R9260, the emitter of the NPN transistor Q4506 is connected to the TX circuit, and the collector of the NPN transistor Q4506 is connected to the HDMI_RXDDC_SDA_PORT circuit;

[0013] An NPN transistor Q4507, wherein the collector of the NPN transistor Q4507 is connected to the first end of the resistor R9260, and the emitter of the NPN transistor Q4507 is grounded;

[0014] a resistor R9261, wherein a first end of the resistor R9261 is connected to the emitter of the NPN transistor Q4507, and a second end of the resistor R9261 is connected to the base of the NPN transistor Q4507;

[0015] a resistor R9262, wherein a second end of the resistor R9262 is connected to a base of an NPN transistor Q4507, and a second end of the resistor R9262 is connected to a VCC5V_HDMIRX_PORT circuit;

[0016] The RX circuit is respectively connected to the second end of the resistor R9100 and the first end of the electrostatic protection diode ED9101, the second end of the electrostatic protection diode ED9101 is grounded, and the first end of the resistor R9100 is connected to the UART2_RX_MO_DEBUG circuit;

[0017] The TX circuit is respectively connected to the second end of the resistor R9101 and the first end of the electrostatic protection diode ED9100, the second end of the electrostatic protection diode ED9100 is grounded, and the first end of the resistor R9101 is connected to the UART2_TX_MO_DEBUG circuit;

[0018] The HDMI modification circuit includes a 19-pin terminal, wherein the 15th pin SCL of the 19-pin terminal is connected to the HDMI_RXDDC_SCL_PORT circuit, and the HDMI_RXDDC_SCL_PORT circuit is further connected to the second end of the resistor R4501, the first end of the resistor R4501 is connected to the cathode of the diode D4500, and the positive end of the diode D4500 is connected to the VCC5V_HDMIRX_PORT circuit;

[0019] The 16th pin SDA of the 19-pin terminal is connected to the HDMI_RXDDC_SDA_PORT circuit, the HDMI_RXDDC_SDA_PORT circuit is connected to the second end of a resistor R4500, and the second end of the resistor R4500 is connected to the negative terminal of the diode D4500;

[0020] The 17th pin GND of the 19-pin terminal is grounded.

[0021] Furthermore, the 18th pin of the 19-pin terminal is connected to a first end of a capacitor C4500 and a VCC5V_HDMIRX_PORT circuit, and a second end of the capacitor C4500 is grounded.

[0022] Furthermore, the VCC5V_HDMIRX_PORT circuit is also connected to the first end of the resistor R4502, the second end of the resistor R4502 is respectively connected to the base of the NPN transistor Q4500 and the first end of the resistor R4503, the second end of the resistor R4503 is grounded, the emitter of the NPN transistor Q4500 is grounded, and the collector of the NPN transistor Q4500 is connected to the HDMIRX_DET_L circuit.

[0023] Compared with the prior art, the beneficial effects of the present invention are:

[0024] 1. The switching circuit of the utility model is realized by modifying the HDMI circuit, so that the UART serial port can be debugged and the logcat information can be viewed on the whole device with an HDMI IN interface without disassembling or damaging the product.

[0025] 2. The switching circuit of the utility model realizes serial communication of the HDMI IN interface based on a modified serial cable.

[0026] 3. The switching circuit of the utility model realizes the coexistence and hardware switching of HDMI IN and UART functions. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 This is a principle block diagram of the switching circuit of the utility model.

[0028] Figure 2-Figure 7 After connection, it becomes the overall diagram of the triode switching circuit of the utility model. DETAILED DESCRIPTION

[0029] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention, so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more specific definition of the scope of protection of the present invention. Obviously, the embodiments described in the present invention are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0031] Example 1: The specific structure of the utility model is as follows:

[0032] Please refer to the attached Figure 1-7, the utility model is a switching circuit for realizing HDMI RX and URAT debugging based on modified HDMI line, including a triode switching circuit and an HDMI modification circuit;

[0033] The triode switching circuit comprises:

[0034] NPN transistor Q4505, the collector of the NPN transistor Q4505 is connected to the RX circuit, and the emitter of the NPN transistor Q4505 is connected to the HDMI_RXDDC_SCL_PORT circuit;

[0035] The resistor R9259 has a second end connected to the base of the NPN transistor Q4505;

[0036] A resistor R9258, having a first end connected to the VCC5V0 power supply and a second end connected to the first end of the resistor R9259;

[0037] a resistor R9260, a first end of which is connected to the first end of the resistor R9259;

[0038] An NPN transistor Q4506, wherein the base of the NPN transistor Q4506 is connected to the second end of the resistor R9260, the emitter of the NPN transistor Q4506 is connected to the TX circuit, and the collector of the NPN transistor Q4506 is connected to the HDMI_RXDDC_SDA_PORT circuit;

[0039] An NPN transistor Q4507, wherein the collector of the NPN transistor Q4507 is connected to the first end of the resistor R9260, and the emitter of the NPN transistor Q4507 is grounded;

[0040] a resistor R9261, wherein a first end of the resistor R9261 is connected to the emitter of the NPN transistor Q4507, and a second end of the resistor R9261 is connected to the base of the NPN transistor Q4507;

[0041] a resistor R9262, wherein a second end of the resistor R9262 is connected to a base of an NPN transistor Q4507, and a second end of the resistor R9262 is connected to a VCC5V_HDMIRX_PORT circuit;

[0042] The RX circuit is respectively connected to the second end of the resistor R9100 and the first end of the electrostatic protection diode ED9101, the second end of the electrostatic protection diode ED9101 is grounded, and the first end of the resistor R9100 is connected to the UART2_RX_MO_DEBUG circuit;

[0043] The TX circuit is respectively connected to the second end of the resistor R9101 and the first end of the electrostatic protection diode ED9100, the second end of the electrostatic protection diode ED9100 is grounded, and the first end of the resistor R9101 is connected to the UART2_TX_MO_DEBUG circuit;

[0044] The HDMI modification circuit includes a 19-pin terminal, wherein the 15th pin SCL of the 19-pin terminal is connected to the HDMI_RXDDC_SCL_PORT circuit, and the HDMI_RXDDC_SCL_PORT circuit is further connected to the second end of the resistor R4501, the first end of the resistor R4501 is connected to the cathode of the diode D4500, and the positive end of the diode D4500 is connected to the VCC5V_HDMIRX_PORT circuit;

[0045] The 16th pin SDA of the 19-pin terminal is connected to the HDMI_RXDDC_SDA_PORT circuit, the HDMI_RXDDC_SDA_PORT circuit is connected to the second end of a resistor R4500, and the second end of the resistor R4500 is connected to the negative terminal of the diode D4500;

[0046] The 17th pin GND of the 19-pin terminal is grounded.

[0047] The 18th pin of the 19-pin terminal is connected to a first end of a capacitor C4500 and a VCC5V_HDMIRX_PORT circuit, and a second end of the capacitor C4500 is grounded.

[0048] The VCC5V_HDMIRX_PORT circuit is also connected to the first end of the resistor R4502, the second end of the resistor R4502 is respectively connected to the base of the NPN transistor Q4500 and the first end of the resistor R4503, the second end of the resistor R4503 is grounded, the emitter of the NPN transistor Q4500 is grounded, and the collector of the NPN transistor Q4500 is connected to the HDMIRX_DET_L circuit.

[0049] The following is the working principle of the switching circuit for realizing HDMI RX and URAT debugging based on the modified HDMI cable of the utility model:

[0050] Prerequisite: Modify the HDMI cable, one end is USB serial port, the other end is HDMI male socket, the TX pin, RX pin and GND pin of the serial port are connected to the SDA pin, SCL pin and GND pin of the HDMI interface, such as Figure 4 The 16-pin SDA, 15-pin SCL and 17-pin GND.

[0051] When the utility model is connected to an HDMI IN device, it has a 5V input characteristic. In conjunction with the characteristic that the modified HDMI serial port line does not have a 5V voltage input, the conduction of each transistor is controlled to realize the switching between the HDMI IN circuit and the UART serial port circuit. When the product is assembled into a complete machine, the UART serial port communication is used to send commands to the product and read Logcat and other information without destroying or disassembling the product.

[0052] Implementation principle:

[0053] 1. Modify the serial cable. The 15-pin SCL, 16-pin SDA, and 17-pin GND of the HDMI interface are the SCL signal pin, SDA signal pin, and GND signal pin respectively. The modified cable corresponds to the TX signal, RX signal, and GND signal. Because the modified cable does not have a 5V input, after insertion, the NPN transistor Q4507 is not conducting, and the bases of the NPN transistor Q4505 and the NPN transistor Q4506 are connected to 5V. The NPN transistor Q4505 and the NPN transistor Q4506 are both turned on. Because uart is a TTL circuit, only the change of 01 is required to communicate. The TX pin of the modified cable is connected to the emitter of the NPN transistor Q4505, and the RX of the motherboard is connected to the collector of the NPN transistor Q4505. When this end of the serial cable sends a 0 1 signal, the master control can receive a 0 1 signal to achieve communication. The RX of the modified line is connected to the collector of the NPN transistor Q4506, and the TX of the mainboard is connected to the emitter of the NPN transistor Q4506. The TX of the mainboard sends a 0 1 signal, and the RX of the serial port line can receive a 0 1 signal to achieve communication.

[0054] 2. The HDMI IN interface is inserted through the HDMI video cable for signal transmission. At the same time, there will be a +5V voltage input to the 18th pin of the HDMI interface. The voltage of the 18th PIN pin is connected to the base of the NPN transistor Q4507 through the voltage divider circuit. At this time, the emitter and collector of the NPN transistor Q4507 are turned on, and the bases of the NPN transistor Q4505 and the NPN transistor Q4506 are pulled down to 0. At this time, the NPN transistor Q4505 and the NPN transistor Q4506 are cut off and not conducting. The circuit switches to the HDMI IN circuit, and the two signal lines of the HDMI_RXDDC_SDA_PORT circuit and the HDMI_RXDDC_SCL_PORT circuit are directly connected to the SOC chip to realize the HDMI IN circuit function.

[0055] In summary, the switching circuit of the present invention, by modifying the HDMI circuit, enables UART serial port debugging and logcat information viewing on a complete device with an HDMI IN interface without disassembling or damaging the device. The switching circuit of the present invention implements serial communication for the HDMI IN interface using a modified serial cable. The switching circuit of the present invention enables coexistence of HDMI IN and UART functions, as well as hardware switching.

[0056] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A switching circuit for HDMI RX and URAT debugging based on a modified HDMI cable, characterized in that: Including transistor switching circuit and HDMI modification circuit; The triode switching circuit comprises: NPN transistor Q4505, the collector of the NPN transistor Q4505 is connected to the RX circuit, and the emitter of the NPN transistor Q4505 is connected to the HDMI_RXDDC_SCL_PORT circuit; The resistor R9259 has a second end connected to the base of the NPN transistor Q4505; A resistor R9258, having a first end connected to the VCC5V0 power supply and a second end connected to the first end of the resistor R9259; a resistor R9260, a first end of which is connected to the first end of the resistor R9259; An NPN transistor Q4506, wherein the base of the NPN transistor Q4506 is connected to the second end of the resistor R9260, the emitter of the NPN transistor Q4506 is connected to the TX circuit, and the collector of the NPN transistor Q4506 is connected to the HDMI_RXDDC_SDA_PORT circuit; An NPN transistor Q4507, wherein the collector of the NPN transistor Q4507 is connected to the first end of the resistor R9260 and the emitter thereof is grounded; a resistor R9261, wherein a first end of the resistor R9261 is connected to the emitter of the NPN transistor Q4507, and a second end of the resistor R9261 is connected to the base of the NPN transistor Q4507; a resistor R9262, wherein a second end of the resistor R9262 is connected to a base of an NPN transistor Q4507, and a second end of the resistor R9262 is connected to a VCC5V_HDMIRX_PORT circuit; The RX circuit is respectively connected to the second end of the resistor R9100 and the first end of the electrostatic protection diode ED9101, the second end of the electrostatic protection diode ED9101 is grounded, and the first end of the resistor R9100 is connected to the UART2_RX_MO_DEBUG circuit; The TX circuit is respectively connected to the second end of the resistor R9101 and the first end of the electrostatic protection diode ED9100, the second end of the electrostatic protection diode ED9100 is grounded, and the first end of the resistor R9101 is connected to the UART2_TX_MO_DEBUG circuit; The HDMI modification circuit includes a 19-pin terminal, wherein the 15th pin SCL of the 19-pin terminal is connected to the HDMI_RXDDC_SCL_PORT circuit, and the HDMI_RXDDC_SCL_PORT circuit is further connected to the second end of the resistor R4501, the first end of the resistor R4501 is connected to the cathode of the diode D4500, and the positive end of the diode D4500 is connected to the VCC5V_HDMIRX_PORT circuit; The 16th pin SDA of the 19-pin terminal is connected to the HDMI_RXDDC_SDA_PORT circuit, the HDMI_RXDDC_SDA_PORT circuit is connected to the second end of a resistor R4500, and the second end of the resistor R4500 is connected to the negative terminal of the diode D4500; The 17th pin GND of the 19-pin terminal is grounded.

2. The switching circuit for realizing HDMI RX and URAT debugging based on a modified HDMI line according to claim 1, characterized in that: The 18th pin of the 19-pin terminal is connected to a first end of a capacitor C4500 and a VCC5V_HDMIRX_PORT circuit, and a second end of the capacitor C4500 is grounded.

3. The switching circuit for realizing HDMI RX and URAT debugging based on a modified HDMI line according to claim 2, characterized in that: The VCC5V_HDMIRX_PORT circuit is also connected to the first end of the resistor R4502, the second end of the resistor R4502 is respectively connected to the base of the NPN transistor Q4500 and the first end of the resistor R4503, the second end of the resistor R4503 is grounded, the emitter of the NPN transistor Q4500 is grounded, and the collector of the NPN transistor Q4500 is connected to the HDMIRX_DET_L circuit.

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