JTAG (Joint Test Action Group) communication on-off circuit for remotely controlling rack

Abstract

The utility model relates to the technical field of steering systems, in particular to a JTAG (Joint Test Action Group) communication on-off circuit for remotely controlling a rack. A JTAG communication on-off circuit for a remote console rack comprises a microcontroller circuit, a USB interface module, a multi-channel connection interface connection circuit and a relay connection circuit, and is characterized in that the microcontroller circuit is respectively connected with the USB interface module and the multi-channel connection interface connection circuit, and the multi-channel connection interface connection circuit is connected with the relay connection circuit. Compared with the prior art, independent control of multiple paths of equipment is realized through the microcontroller and the independent relay driving circuit, and independent operation and non-interference of the equipment are ensured; an external computer is connected through the USB interface, so that transmission, programming and debugging of remote instructions are realized; the reliability of the system is improved; and each control channel adopts a modular design, so that the system is convenient to expand and maintain, and the channels can be increased or reduced according to requirements to adapt to different application scenes.

Description

Technical Field

[0001] This utility model relates to the field of steering system technology, specifically to a JTAG communication on / off circuit for remote control of a chassis. Background Technology

[0002] In the existing technology, due to software flashing issues, when loading the test program into the steering system ECU, if the JTAG communication is not disconnected, the steering system controller cannot switch to the corresponding mode for software flashing. Under normal working or home office conditions, it is necessary to manually disconnect the circuit at the test bench to switch modes and flash the program, and to reconnect the JTAG line normally after the software flashing is completed, which seriously restricts the testing efficiency.

[0003] If the connector is physically disconnected, it will be exposed on the test bench, posing a safety risk and failing to meet the increasingly stringent safety requirements of automotive R&D. Summary of the Invention

[0004] To overcome the shortcomings of the prior art, this utility model provides an optimized modular design and protection mechanism for remote control rack JTAG communication on / off circuits, featuring high stability, high scalability, and multifunctionality.

[0005] To achieve the above objectives, a remote control rack JTAG communication on / off circuit is designed, comprising a microcontroller circuit, a USB interface module, a multi-channel connection interface circuit, and a relay connection circuit. The microcontroller circuit is connected to the USB interface module and the multi-channel connection interface circuit, respectively, and the multi-channel connection interface circuit is connected to the relay connection circuit.

[0006] The microcontroller circuit includes a first microcontroller chip, a second microcontroller chip, and a USB chip; the USB interface module includes a USB interface chip.

[0007] Port 6 of the first microcontroller chip is connected to port 3 of the USB chip, port 1 of the USB interface chip, port 2 of the first terminal block, and one end of the first resistor. The other end of the first resistor is connected to port 1 of the second terminal block. Port 7 of the first microcontroller chip is connected to port 2 of the USB chip, port 2 of the USB interface chip, and port 3 of the first terminal block. Port 1 of the first terminal block is grounded. Port 4 of the first terminal block is connected to the VCC power supply. Port 8 of the first microcontroller chip is grounded. Port 9 of the first microcontroller chip is connected to the VCC power supply, one end of the second resistor, and one end of the first capacitor. The other end of the first capacitor is grounded, and the other end of the second resistor is connected to the first... The anode of the first LED and the cathode of the first LED are connected to one end of the third resistor, one end of the fourth resistor, one end of the fifth resistor, one end of the sixth resistor, and ground, respectively. The other end of the third resistor is connected to port 7 of the second microcontroller chip, one end of the seventh resistor, and port 1 of the first microcontroller chip, respectively. The other end of the seventh resistor is connected to one end of the eighth resistor and the base of the first transistor. The emitter of the first transistor and the other end of the eighth resistor are combined and grounded, and the collector of the first transistor is grounded. The other end of the fourth resistor is connected to port 8 of the second microcontroller chip, one end of the ninth resistor, and port 2 of the first microcontroller chip, respectively. The other end of the ninth resistor is connected to one end of the tenth resistor and the base of the second transistor, respectively. The emitter of the second transistor and the other end of the tenth resistor are connected together and grounded; the collector of the second transistor is grounded. The other end of the fifth resistor is connected to port 1 of the second microcontroller chip, one end of the eleventh resistor, and port 3 of the first microcontroller chip. The other end of the eleventh resistor is connected to one end of the twelfth resistor and the base of the third transistor; the emitter of the third transistor and the other end of the twelfth resistor are connected together and grounded; the collector of the third transistor is grounded. The other end of the sixth resistor is connected to port 3 of the second microcontroller chip, one end of the thirteenth resistor, and port 4 of the first microcontroller chip. The other end of the thirteenth resistor is connected to one end of the fourteenth resistor and the base of the fourth transistor; the emitter of the fourth transistor and the other end of the fourteenth resistor are connected together. Grounded; the collector of the fourth transistor is grounded; port 10 of the first microcontroller chip is connected to one end of the second capacitor, port 8 of the USB interface chip, and port 2 of the second terminal block, respectively, and the other end of the second capacitor is grounded; port 1 of the USB chip is connected to the VCC power supply, and port 5 of the USB chip is grounded; port 3 of the USB interface chip is grounded, port 5 of the USB interface chip is connected to the VCC power supply, port 6 of the USB interface chip is connected to port 5 of the second microcontroller chip, port 7 of the USB interface chip is connected to port 6 of the second microcontroller chip, port 2 of the second microcontroller chip is connected to the VCC power supply, and port 4 of the second microcontroller chip is connected to one end of the fifteenth resistor and grounded;The other end of the fifteenth resistor is grounded.

[0008] The collector of the first transistor is connected to the anode of the first Zener diode and one end of the sixteenth resistor, the other end of the sixteenth resistor is connected to the cathode of the first LED, and the anode of the first LED and the cathode of the first Zener diode are connected together to the VCC power supply; the collector of the second transistor is connected to the anode of the second Zener diode and one end of the seventeenth resistor, the other end of the seventeenth resistor is connected to the cathode of the second LED, and the anode of the second LED and the cathode of the second Zener diode are connected together to the VCC power supply; the collector of the third transistor is connected to the anode of the third Zener diode and one end of the eighteenth resistor, the other end of the eighteenth resistor is connected to the cathode of the third LED, and the anode of the third LED and the cathode of the third Zener diode are connected together to the VCC power supply; the collector of the fourth transistor is connected to the anode of the fourth Zener diode and one end of the nineteenth resistor, the other end of the nineteenth resistor is connected to the cathode of the fourth LED, and the anode of the fourth LED and the cathode of the fourth Zener diode are connected together to the VCC power supply.

[0009] The first microcontroller chip is model CH554E; the second microcontroller chip is model STC8G1K08A.

[0010] The USB chip is model MicroUSB-5PIN; the USB interface chip is model CH340N.

[0011] The multi-channel connection interface circuit includes a multi-channel connection terminal and several relays; the NETPORT1 port of the multi-channel connection terminal is connected to port 3 of the first relay, the NET2 port of the multi-channel connection terminal is connected to port 5 of the first relay, the NET1 port of the multi-channel connection terminal is connected to port 2 of the first relay, port 1 of the first relay is grounded, and port 4 of the first relay is connected to VCC power supply; the NET4 port of the multi-channel connection terminal is connected to port 2 of the second relay, the NET5 port of the multi-channel connection terminal is connected to port 5 of the second relay, the NET6 port of the multi-channel connection terminal is connected to port 3 of the second relay, and port 1 of the second relay is grounded. The 4th port of the second relay is connected to the VCC power supply; the NET7 port of the multi-channel connection terminal is connected to the 2nd port of the third relay, the NET8 port of the multi-channel connection terminal is connected to the 5th port of the third relay, the NET9 port of the multi-channel connection terminal is connected to the 3rd port of the third relay, the 1st port of the third relay is grounded, and the 4th port of the third relay is connected to the VCC power supply; the NET10 port of the multi-channel connection terminal is connected to the 2nd port of the fourth relay, the NET11 port of the multi-channel connection terminal is connected to the 5th port of the fourth relay, the NET12 port of the multi-channel connection terminal is connected to the 3rd port of the fourth relay, the 1st port of the fourth relay is grounded, and the 4th port of the fourth relay is connected to the VCC power supply.

[0012] The multi-channel connection terminal is model PZ2.54-1*12; the first relay, second relay, third relay, and fourth relay are model SRD-05VDC-SL-C.

[0013] The multi-channel connection interface circuit connects five relays through port 1 of the first relay and connects them in parallel to one IO port; the second, third, and fourth relays are redundantly configured and are connected to three other IO ports.

[0014] Compared with existing technologies, this invention achieves individual control of multiple devices through a microcontroller and independent relay drive circuits, ensuring independent operation and non-interference of each device, making it suitable for multi-device control needs. It connects to an external computer via a USB interface, enabling remote command transmission, programming, and debugging, thus providing flexibility and ease of operation. The combination of reverse diodes, filter capacitors, and current-limiting resistors protects the microcontroller and drive circuits from interference from high voltage, back electromotive force, and high-frequency noise, improving system reliability. Each control channel adopts a modular design, facilitating system expansion and maintenance; channels can be added or removed as needed to adapt to different application scenarios. Attached Figure Description

[0015] Figure 1 This is the circuit connection diagram of this utility model.

[0016] Figure 2 This is a circuit diagram showing the connection between the microcontroller circuit and the USB interface module in this utility model.

[0017] Figure 3 This is a circuit diagram showing the connection between the multi-channel connection interface circuit and the relay in this utility model. Detailed Implementation

[0018] The present invention will be further described below with reference to the accompanying drawings.

[0019] like Figure 1 As shown, the circuit of this utility model consists of a microcontroller circuit, a USB interface module, a multi-channel connection interface circuit, and a relay. The microcontroller circuit is connected to the USB interface module and the multi-channel connection interface circuit respectively.

[0020] The microcontroller circuit includes a first microcontroller chip U1, a second microcontroller chip U3, and a USB chip U4. The USB interface module includes a USB interface chip U2. Port 6 of the first microcontroller chip U1 is connected to port 3 of the USB chip U4, port 1 of the USB interface chip U2, port 2 of the first terminal block H4, and one end of the first resistor R26. The other end of the first resistor R26 is connected to port 1 of the second terminal block H3. Port 7 of the first microcontroller chip U1 is connected to port 2 of the USB chip U4, port 2 of the USB interface chip U2, and port 3 of the first terminal block H4. Port 1 of the first terminal block H4 is grounded. Port 4 is connected to the VCC power supply; port 8 of the first microcontroller chip U1 is grounded; port 9 of the first microcontroller chip U1 is connected to the VCC power supply, one end of the second resistor R28, and one end of the first capacitor C3, with the other end of the first capacitor C3 grounded; the other end of the second resistor R28 is connected to the anode of the first LED D10; the cathode of the first LED D10 is connected to one end of the third resistor R22, one end of the fourth resistor R23, one end of the fifth resistor R35, one end of the sixth resistor R36, and grounded; the other end of the third resistor R22 is connected to port 7 of the second microcontroller chip U3, one end of the seventh resistor R20, and port 1 of the first microcontroller chip U1; the seventh resistor R20... The other end of the resistor is connected to one end of the eighth resistor R24 ​​and the base of the first transistor Q5. The emitter of the first transistor Q5 and the other end of the eighth resistor R24 ​​are grounded together, and the collector of the first transistor Q5 is grounded. The other end of the fourth resistor R23 is connected to port 8 of the second microcontroller chip U3, one end of the ninth resistor R19, and port 2 of the first microcontroller chip U1. The other end of the ninth resistor R19 is connected to one end of the tenth resistor R21 and the base of the second transistor Q6. The emitter of the second transistor Q6 and the other end of the tenth resistor R21 are grounded together, and the collector of the second transistor Q6 is grounded. The other end of the fifth resistor R35 is connected to port 1 of the second microcontroller chip U3 and the eleventh resistor R24. One end of resistor R29 is connected to port 3 of the first microcontroller chip U1; the other end of the eleventh resistor R29 is connected to one end of the twelfth resistor R30 and the base of the third transistor Q7, the emitter of the third transistor Q7 and the other end of the twelfth resistor R30 are grounded together, and the collector of the third transistor Q7 is grounded; the other end of the sixth resistor R36 is connected to port 3 of the second microcontroller chip U3, one end of the thirteenth resistor R32 and port 4 of the first microcontroller chip U1; the other end of the thirteenth resistor R32 is connected to one end of the fourteenth resistor R33 and the base of the fourth transistor Q8, the emitter of the fourth transistor Q8 and the other end of the fourteenth resistor R33 are grounded together, and the collector of the fourth transistor Q8 is grounded;The first microcontroller chip U1 has its port 10 connected to one end of the second capacitor C4, port 8 of the USB interface chip U2, and port 2 of the second terminal block H3. The other end of the second capacitor C4 is grounded. The USB chip U4 has its port 1 connected to the VCC power supply and its port 5 grounded. The USB interface chip U2 has its port 3 grounded and its port 5 connected to the VCC power supply. Its port 6 is connected to port 5 of the second microcontroller chip U3, its port 7 is connected to port 6 of the second microcontroller chip U3, its port 2 is connected to the VCC power supply, and its port 4 is connected to one end of the fifteenth resistor R37 and grounded. The other end of the fifteenth resistor R37 is grounded.

[0021] The collector of the first transistor Q5 is connected to the anode of the first Zener diode D13 and one end of the sixteenth resistor R25. The other end of the sixteenth resistor R25 is connected to the cathode of the first LED D11. The anode of the first LED D11 and the cathode of the first Zener diode D13 are connected together to the VCC power supply. The collector of the second transistor Q6 is connected to the anode of the second Zener diode D14 and one end of the seventeenth resistor R27. The other end of the seventeenth resistor R27 is connected to the cathode of the second LED D12. The anode of the second LED D12 and the cathode of the second Zener diode D14 are connected together to the VCC power supply. The collector of the third transistor Q7 is connected to the anode of the third Zener diode D16 and one end of the eighteenth resistor R31. The other end of the eighteenth resistor R31 is connected to the cathode of the third LED D15. The anode of the third LED D15 and the cathode of the third Zener diode D16 are connected together to the VCC power supply. The collector of the fourth transistor Q8 is connected to the anode of the fourth Zener diode D18 and one end of the nineteenth resistor R34. The other end of the nineteenth resistor R34 is connected to the cathode of the fourth LED D17. The anode of the fourth LED D17 and the cathode of the fourth Zener diode D18 are connected together to the VCC power supply.

[0022] The first microcontroller chip U1 is model CH554E; the second microcontroller chip U3 is model STC8G1K08A.

[0023] The USB chip U4 is model number MicroUSB-5PIN; the USB interface chip U2 is model number CH340N.

[0024] The multi-channel connection interface circuit includes a multi-channel connection terminal UP2 and several relays. The NETPORT1 port of the multi-channel connection terminal UP2 is connected to port 3 of the first relay PLY5; the NET2 port of the multi-channel connection terminal UP2 is connected to port 5 of the first relay PLY5; the NET1 port of the multi-channel connection terminal UP2 is connected to port 2 of the first relay PLY5; port 1 of the first relay PLY5 is grounded; and port 4 of the first relay PLY5 is connected to the VCC power supply. The NET4 port of the multi-channel connection terminal UP2 is connected to port 2 of the second relay PLY6; the NET5 port of the multi-channel connection terminal UP2 is connected to port 5 of the second relay PLY6; the NET6 port of the multi-channel connection terminal UP2 is connected to port 3 of the second relay PLY6; and port 1 of the second relay PLY6 is grounded. PLY6's port 4 is connected to VCC power; multi-channel connection terminal UP2's NET7 port is connected to the third relay PLY7's port 2, multi-channel connection terminal UP2's NET8 port is connected to the third relay PLY7's port 5, multi-channel connection terminal UP2's NET9 port is connected to the third relay PLY7's port 3, the third relay PLY7's port 1 is grounded, and the third relay PLY7's port 4 is connected to VCC power; multi-channel connection terminal UP2's NET10 port is connected to the fourth relay PLY8's port 2, multi-channel connection terminal UP2's NET11 port is connected to the fourth relay PLY8's port 5, multi-channel connection terminal UP2's NET12 port is connected to the fourth relay PLY8's port 3, the fourth relay PLY8's port 1 is grounded, and the fourth relay PLY8's port 4 is connected to VCC power.

[0025] The multi-channel connection terminal UP2 is model PZ2.54-1*12; the first relay PLY5, the second relay PLY6, the third relay PLY7, and the fourth relay PLY8 are model SRD-05VDC-SL-C.

[0026] The multi-channel connection interface circuit connects five relays through port 1 of the first relay PLY5 and connects them in parallel to one IO port; the second relay PLY6, the third relay PLY7, and the fourth relay PLY8 are redundantly configured and are connected to three other IO ports respectively.

[0027] like Figure 2 The diagram shows the connection circuit between the microcontroller circuit and the USB interface module.

[0028] I. Microcontroller Circuit:

[0029] The microcontroller (e.g., STC8G1K08A-36I5) is the core control unit of this circuit, responsible for receiving instructions and controlling the relays of each channel. It controls the on / off state of each relay through programming, thereby achieving precise switching control of external devices.

[0030] Working principle: The microcontroller outputs high and low levels through GPIO pins to control the drive circuit, which in turn drives the relay. The communication interface supports UART, I2C, and SPI, facilitating communication with external devices and sensors. A crystal oscillator circuit provides the system clock, ensuring stable operation of the microcontroller.

[0031] Key components: STC8G1K08A-36I5 microcontroller, supporting multi-channel control; 12MHz crystal oscillator; 20pF capacitors C3 and C4 for crystal oscillator stabilization.

[0032] II. USB Interface Module:

[0033] The USB interface connects to the microcontroller via the UART interface, enabling data communication with external devices (such as computers) and providing remote programming, control, and debugging capabilities for the microcontroller.

[0034] A protective resistor is connected in series in the circuit to limit the data transmission current and protect the microcontroller and USB module.

[0035] Working principle: The USB data cable D+ and D- are connected to the microcontroller through a current-limiting resistor to ensure stable communication. The USB power supply pin is connected to a filter capacitor to reduce power supply noise interference with communication.

[0036] Key components: 5-pin standard MicroUSB interface.

[0037] like Figure 3 The diagram shows the connection circuit between the multi-channel connection interface and the relay.

[0038] Multi-channel connection interface: The circuit design incorporates multiple NETPORT interfaces for connecting external load devices. Each interface corresponds to a relay, enabling independent control of multiple channels. Each channel's relay is independently controlled by the microcontroller, ensuring no interference and allowing for precise switching control of multiple external devices. Each control channel (including the drive circuit and relay) operates independently, facilitating system expansion. If more channels are needed, relays and drive circuits can be added and connected to unused pins of the microcontroller to meet different application requirements.

[0039] Working principle: Each device corresponds to a relay, which is individually controlled by a microcontroller. More channels can be added by increasing the number of relays and drive circuits.

[0040] Each control channel is equipped with a relay, and the relay is controlled by a drive circuit to control the switching of external devices.

[0041] Each channel's microcontroller GPIO pin is connected to the base of a transistor (such as KT-0805) for signal amplification. The high-level signal output by the microcontroller controls the transistor base through a current-limiting resistor, turning the transistor on and supplying sufficient current to the relay coil to activate the relay.

[0042] It is connected in series between the microcontroller and the transistor base to limit the current and prevent the microcontroller pins from being damaged by large current.

[0043] When the relay receives sufficient current, it activates and its contacts close, connecting the external device to the power supply. When the relay loses power, its contacts open, and the external device is de-energized.

[0044] Working principle: The low current signal output by the microcontroller is amplified by a transistor (S8050 J3Y) to drive the relay to engage. A current-limiting resistor is connected in series with the base to prevent the drive signal from becoming too large.

[0045] This utility model circuit supports independent control of multi-channel devices, facilitating expansion and maintenance; protection circuits and filtering designs ensure reliable device operation; reverse diodes and PTC fuses enhance system protection capabilities; and it supports remote communication, condition triggering, and other functions.

Claims

1. A circuit for remotely controlling a JTAG communication switch, comprising a microcontroller circuit, a USB interface module, a multi-channel connection interface circuit, and a relay connection circuit, characterized in that: The microcontroller circuit is connected with the USB interface module and the multi-channel connection interface connection circuit respectively, and the multi-channel connection interface connection circuit is connected with the relay connection circuit. The microcontroller circuit comprises a first microcontroller chip (U1), a second microcontroller chip (U3) and a USB chip (U4). The No. 6 port of the first microcontroller chip (U1) is connected with the No. 3 port of the USB chip (U4), the No. 1 port of the USB interface chip (U2), the No. 2 port of the first wiring terminal (H4) and one end of the first resistor (R26) respectively, and the other end of the first resistor (R26) is connected with the No. 1 port of the second wiring terminal (H3); the No. 7 port of the first microcontroller chip (U1) is connected with the No. 2 port of the USB chip (U4), the No. 2 port of the USB interface chip (U2) and the No. 3 port of the first wiring terminal (H4) respectively; the No. 1 port of the first wiring terminal (H4) is grounded; the No. 4 port of the first wiring terminal (H4) is connected with the VCC power supply; the No. 8 port of the first microcontroller chip (U1) is grounded; the No. 9 port of the first microcontroller chip (U1) is connected with the VCC power supply, one end of the second resistor (R28) and one end of the first capacitor (C3) respectively, the other end of the first capacitor (C3) is grounded, the other end of the second resistor (R28) is connected with the anode of the first light emitting diode (D10), and the cathode of the first light emitting diode (D10) is connected with one end of the third resistor (R22), one end of the fourth resistor (R23), one end of the fifth resistor (R35), one end of the sixth resistor (R36) and the ground respectively; the other end of the third resistor (R22) is connected with the No. 7 port of the second microcontroller chip (U3), one end of the seventh resistor (R20) and the No. 1 port of the first microcontroller chip (U1) respectively; the other end of the seventh resistor (R20) is connected with one end of the eighth resistor (R24) and the base of the first triode (Q5) respectively, the emitter of the first triode (Q5) and the other end of the eighth resistor (R24) are grounded in common, and the collector of the first triode (Q5) is grounded; the other end of the fourth resistor (R23) is connected with the No. 8 port of the second microcontroller chip (U3), one end of the ninth resistor (R19) and the No. 2 port of the first microcontroller chip (U1) respectively; the other end of the ninth resistor (R19) is connected with one end of the tenth resistor (R21) and the base of the second triode (Q6) respectively, the emitter of the second triode (Q6) and the other end of the tenth resistor (R21) are grounded in common, and the collector of the second triode (Q6) is grounded; the other end of the fifth resistor (R35) is connected with the No. 1 port of the second microcontroller chip (U3), one end of the eleventh resistor (R29) and the No. 3 port of the first microcontroller chip (U1) respectively; the other end of the eleventh resistor (R29) is connected with one end of the twelfth resistor (R30) and the base of the third triode (Q7) respectively, the emitter of the third triode (Q7) and the other end of the twelfth resistor (R30) are grounded in common, and the collector of the third triode (Q7) is grounded; the other end of the sixth resistor (R36) is connected with the No. 3 port of the second microcontroller chip (U3), one end of the thirteenth resistor (R32) and the No. 4 port of the first microcontroller chip (U1) respectively;The other end of the thirteenth resistor (R32) is connected with one end of the fourteenth resistor (R33) and the base of the fourth transistor (Q8) respectively, the emitter of the fourth transistor (Q8) and the other end of the fourteenth resistor (R33) are connected with ground, and the collector of the fourth transistor (Q8) is grounded; the No.10 port of the first microcontroller chip (U1) is connected with one end of the second capacitor (C4), the No.8 port of the USB interface chip (U2) and the No.2 port of the second terminal (H3) respectively, and the other end of the second capacitor (C4) is grounded; the No.1 port of the USB chip (U4) is connected with the VCC power supply, and the No.5 port of the USB chip (U4) is grounded; the No.3 port of the USB interface chip (U2) is grounded, the No.5 port of the USB interface chip (U2) is connected with the VCC power supply, the No.6 port of the USB interface chip (U2) is connected with the No.5 port of the second microcontroller chip (U3), the No.7 port of the USB interface chip (U2) is connected with the No.6 port of the second microcontroller chip (U3), the No.2 port of the second microcontroller chip (U3) is connected with the VCC power supply, the No.4 port of the second microcontroller chip (U3) is connected with one end of the fifteenth resistor (R37) and the ground respectively, and the other end of the fifteenth resistor (R37) is grounded.

2. A remote console JTAG communication circuit for a rack according to claim 1, wherein: The anode of the first light-emitting diode (D11) and the cathode of the first voltage stabilizing diode (D13) are connected with a VCC power supply; the anode of the second light-emitting diode (D12) and the cathode of the second voltage stabilizing diode (D14) are connected with the VCC power supply; the anode of the third light-emitting diode (D15) and the cathode of the third voltage stabilizing diode (D16) are connected with the VCC power supply; and the anode of the fourth light-emitting diode (D17) and the cathode of the fourth voltage stabilizing diode (D18) are connected with the VCC power supply.

3. A remote console JTAG communication circuit for a rack according to claim 1, wherein: The first microcontroller chip (U1) is CH554E; and the second microcontroller chip (U3) is STC8G1K08A.

4. A remote console JTAG communication circuit for a rack according to claim 1, wherein: The USB chip (U4) is MicroUSB-5PIN; and the USB interface chip (U2) is CH340N.

5. A remote console JTAG communication circuit for a rack according to claim 1, wherein: The multi-channel connection interface connecting circuit comprises a multi-channel connection terminal (UP2) and a plurality of relays; a NETPORT1 port of the multi-channel connection terminal (UP2) is connected with a No. 3 port of a first relay (PLY5), a NET2 port of the multi-channel connection terminal (UP2) is connected with a No. 5 port of the first relay (PLY5), a NET1 port of the multi-channel connection terminal (UP2) is connected with a No. 2 port of the first relay (PLY5), a No. 1 port of the first relay (PLY5) is grounded, and a No. 4 port of the first relay (PLY5) is connected with a VCC power supply; a NET4 port of the multi-channel connection terminal (UP2) is connected with a No. 2 port of a second relay (PLY6), a NET5 port of the multi-channel connection terminal (UP2) is connected with a No. 5 port of the second relay (PLY6), a NET6 port of the multi-channel connection terminal (UP2) is connected with a No. 3 port of the second relay (PLY6), a No. 1 port of the second relay (PLY6) is grounded, and a No. 4 port of the second relay (PLY6) is connected with the VCC power supply; a NET7 port of the multi-channel connection terminal (UP2) is connected with a No. 2 port of a third relay (PLY7), a NET8 port of the multi-channel connection terminal (UP2) is connected with a No. 5 port of the third relay (PLY7), a NET9 port of the multi-channel connection terminal (UP2) is connected with a No. 3 port of the third relay (PLY7), a No. 1 port of the third relay (PLY7) is grounded, and a No. 4 port of the third relay (PLY7) is connected with the VCC power supply; a NET10 port of the multi-channel connection terminal (UP2) is connected with a No. 2 port of a fourth relay (PLY8), a NET11 port of the multi-channel connection terminal (UP2) is connected with a No. 5 port of the fourth relay (PLY8), a NET12 port of the multi-channel connection terminal (UP2) is connected with a No. 3 port of the fourth relay (PLY8), a No. 1 port of the fourth relay (PLY8) is grounded, and a No. 4 port of the fourth relay (PLY8) is connected with the VCC power supply.

6. A remote console JTAG communication circuit for a rack according to claim 5, wherein: The multi-channel connection terminal (UP2) is of a PZ2.54-1*12 type; the first relay (PLY5), the second relay (PLY6), the third relay (PLY7) and the fourth relay (PLY8) are of an SRD-05VDC-SL-C type.

7. A remote console JTAG communication circuit for a rack according to claim 5, wherein: The multi-channel connection interface connecting circuit is connected with the five relays through the No. 1 port of the first relay (PLY5) and is connected in parallel to one IO port; the second relay (PLY6), the third relay (PLY7) and the fourth relay (PLY8) are redundantly arranged, and the second relay (PLY6), the third relay (PLY7) and the fourth relay (PLY8) are connected to the other three IO ports, respectively.

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