A domestic KVM switching system

Abstract

The present invention relates to a domestic KVM switching system, belonging to the field of computer system design. The present invention obtains DVI / HDMI input signals from two external main processor boards A and B, and performs KVM output switching and indication according to the current state by responding to external switching buttons or serial commands. The output interfaces include a DVI / HDMI output interface directly connected to the device, a USB power supply interface, two USB data differential interfaces, and two switching indicators that can directly indicate that the current output state is machine A or machine B, a DVI / HDMI debugging output interface related to debugging, and two debugging indicators. The software and hardware of this system can achieve a 100% domestic production rate.

Description

Technical Field

[0001] The present invention belongs to the field of computer system design, and particularly relates to a domestic KVM switching system. Background Art

[0002] A KVM (Keyboard, Video, Mouse) switching system can be used to perform display control on two or more computers by using only one set of computer peripheral devices.

[0003] The KVM switching system is applied to a display control device with a dual-mainboard redundant design. The mainboard A and the mainboard B can switch the roles of the working machine and the backup machine through buttons or software, and a set of keyboard, mouse, and display need to be multiplexed time-divisionally. The mainboard A, the mainboard B, and the switching board are interconnected through the backplane for signals. The keyboard and mouse interfaces of the traditional switching board are PS / 2, and the timing logic needs to be completed through an FPGA, which is relatively complex to implement and has a high cost. The video signal of the traditional switching board only realizes one-for-N switching. Summary of the Invention

[0004] (1) Technical Problems to be Solved

[0005] The technical problem to be solved by the present invention is how to provide a domestic KVM switching system to solve the problems that the keyboard and mouse interfaces of the traditional switching board are PS / 2, the timing logic needs to be completed through an FPGA, which is relatively complex to implement and has a high cost, and the video signal of the traditional switching board only realizes one-for-N switching.

[0006] (2) Technical Solutions

[0007] To solve the above technical problems, the present invention proposes a domestic KVM switching system. The KVM switching system is a switching board, including: a power supply module, a main control chip, two EEPROMs, a video signal switching module, a keyboard and mouse signal switching module, and an indicator light module;

[0008] The power supply module is responsible for supplying power to the switching system, stepping down the external 12V to 5V and 3.3V. Among them, 5V is used to supply power to the video signal switching module and external USB keyboard and mouse devices, and 3.3V is used to supply power to the main control chip;

[0009] The main control chip is the core component for switching and controlling the DVI signals and USB signals from machine A and machine B, serial communication, digital input, and LED indicator light control;

[0010] Two EEPROMs are used to store the EDID information of the display. The two EEPROMs are respectively connected to the graphics cards of machine A and machine B through the backplane. When machine A and machine B are powered on simultaneously, the graphics cards of the two machines read different EEPROMs on the switching board at the same time, and the video output is configured in the format required by the display;

[0011] The video signal switching module selects a DVI / HDMI 2:4 TMDS interface fan-out buffer chip. The two inputs are DVI input signals from Machine A and Machine B, and the output is two fan-out DVI output signals. One is output to the display control device through the backplane, and the other is directly output from the switching board for debugging. Both outputs can control the switching of the DVI signals of Machine A and Machine B.

[0012] The keyboard and mouse signal switching module is implemented using electromagnetic relays. The switching of the differential signals of the USB mouse and keyboard data is achieved in two levels. In the first level, a double-pole double-throw electromagnetic relay is used to select one of the differential signals of the USB mouse and keyboard from Machine A or Machine B and output it to the second level. The second level also uses a double-pole double-throw electromagnetic relay to select whether to connect or disconnect the differential signals of the keyboard and mouse data output from the first level to the backplane. For the USB switching of the keyboard or mouse, it is necessary to control the power-on and power-off timing of the external mouse and keyboard simultaneously. The microcontroller GPIO generates a control signal to control whether to output the 5V and GND of the switching board itself to the external USB keyboard and mouse devices, and a double-pole double-throw electromagnetic relay is used to achieve the simultaneous on-off control of 5V and GND.

[0013] The switching board also leads out three UART signals through the microcontroller. Two of them are RS232, which are respectively connected to the serial ports of Machine A and Machine B through the backplane. Machine A and Machine B can query the working status of the switching board and the KVM switching control through the RS232 serial port. The third one is a UART serial port signal with a 3.3V TTL level led out through the microcontroller inside the switching board, for the debugging personnel to query the working status of the switching board and the KVM switching control from the debugging serial port.

[0014] The switching board outputs 2 LED indicator control signals externally, indicating which main processing board currently has the control of the KVM. The switching board has 1 debugging serial port and 2 microcontroller debugging indicator lights. The debugging personnel can query the current switching status and the KVM control through the serial port. The switching board collects external button signals and switches according to the current KVM display status.

[0015] (III) Beneficial effects

[0016] The present invention proposes a domestic KVM switching system. The present invention replaces the keyboard and mouse interfaces with USB interfaces and completes the switching of USB control signals through domestic electromagnetic relays, greatly simplifying the design and reducing costs.

[0017] The domestic JMX3845 chip used in the present invention can achieve 2 DVI / HDMI inputs fan out 4 DVI / HDMI outputs, providing a video output debugging interface in the display control device with dual-board redundancy for the debugging personnel to view the display status of Machine A and Machine B simultaneously.

[0018] The present invention obtains DVI / HDMI input signals from two external main processor boards A and B, and performs KVM output switching and indication according to the current state by responding to external switching buttons or serial commands. The output interfaces include a DVI / HDMI output interface directly connected to the device, a USB power supply interface, two USB data differential interfaces, and two switching indicators that can directly indicate that the current output state is machine A or machine B, a DVI / HDMI debugging output interface related to debugging, and two debugging indicators. The software and hardware of this system can achieve a 100% domestic production rate. Description of the Drawings

[0019] Figure 1 It is a schematic diagram of the connection of the external video EDID signal of the switching board in the prior art;

[0020] Figure 2 It is a principle block diagram of the KVM switching system of the present invention. Detailed Embodiment

[0021] To make the objectives, contents, and advantages of the present invention clearer, the following further describes in detail the specific embodiments of the present invention with reference to the drawings and embodiments.

[0022] The present invention relates to the field of computers, and specifically discloses a domestic KVM switching method and a KVM switching system. The method includes: obtaining DVI / HDMI input signals from two external main processor boards A and B, and performing KVM output switching and indication according to the current state by responding to external switching buttons or serial commands. The output interfaces include a DVI / HDMI output interface directly connected to the device, a USB power supply interface, two USB data differential interfaces, and two switching indicators that can directly indicate that the current output state is machine A or machine B, a DVI / HDMI debugging output interface related to debugging, and two debugging indicators. The software and hardware of this system can achieve a 100% domestic production rate.

[0023] The present invention replaces the keyboard and mouse interfaces with USB interfaces, and completes the switching of USB control signals through domestic electromagnetic relays, greatly simplifying the design and reducing costs.

[0024] The domestic JMX3845 chip used in the present invention can realize 2-way DVI / HDMI input and 4-way DVI / HDMI output, and provides a video output debugging interface in the dual-board redundant display control device for debuggers to view the display states of machine A and machine B at the same time.

[0025] In view of the deficiencies of existing products, the present invention provides a domestic KVM switching method and a KVM switching system. The switching system has achieved full domestic production in the hardware circuit design.

[0026] The KVM switching system of the present invention is a switching board, including: a power supply module, a main control chip, two EEPROMs, a video signal switching module, a keyboard and mouse signal switching module, and an indicator light module;

[0027] The power supply module is responsible for supplying power to the switching system, stepping down the external 12V to 5V and 3.3V. Among them, 5V powers the video signal switching module and external USB keyboard and mouse devices, and 3.3V powers the main control chip. In a certain embodiment, the HCE4644MB type four-channel 4A output, wide voltage input DC / DC converter of Beijing Sevenstar Huachuang Microelectronics Co., Ltd. is selected to step down the external 12V to 5V and 3.3V.

[0028] The main control chip is the core component for switching and controlling the DVI signals and USB signals from machine A and machine B, serial communication, digital input, and LED indicator control. The CS32F103CB type microprocessor of the 58th Research Institute of China Electronics Technology Group Corporation is selected. The CS32F103CB standard series products provide a 48-pin package form, and the code and instructions are completely compatible with the STM32F103CB series digital signal processors, thus ensuring the continuity of project or product design.

[0029] Two EEPROMs are used to store the EDID information of the display. The AiP24C256 type of the 58th Research Institute of China Electronics Technology Group Corporation is selected. The 2 EEPROMs are respectively connected to the graphics cards of machine A and machine B through the bottom plate. When machine A and machine B are powered on simultaneously, the graphics cards of the two machines read different EEPROMs on the switching board at the same time, and the video output is configured in the format required by the display.

[0030] The video signal switching module selects a DVI / HDMI 2:4 TMDS interface fan-out buffer chip. The two inputs are DVI input signals from machine A and machine B, and the output is two fan-out DVI output signals. One is output to the display control device through the bottom plate, and the other is directly output from the switching board for debugging use. Both outputs can control the switching of the DVI signals of machine A and machine B. This buffer chip selects the JMX3845 type of the 58th Research Institute of China Electronics Technology Group Corporation, which is compatible with the MAX3845 chip of the US MAXIM company and can withstand the multiplexing of DVI or HDMI signals with a maximum of 1.65 Gbps.

[0031] The keyboard and mouse signal switching module is implemented using an electromagnetic relay. In a certain embodiment, the JRC-089M / 005-02-II type electromagnetic relay of Guizhou Aerospace Electric Co., Ltd. is selected. The switching of the USB mouse and keyboard data differential signals is realized in two levels.

[0032] The first stage uses a double-pole double-throw electromagnetic relay to select one of the differential signals of the USB mouse and keyboard of machine A or machine B and output it to the second stage. Figure 2 As shown, when the MCU GPIO outputs a low level to this relay control pin, the electromagnetic coil is not turned on, the normally closed contact remains closed, the normally open contact remains open, and the USB keyboard data differential signal of machine A and the USB mouse data differential signal of machine A will be output to the second stage; when the MCU GPIO outputs a high level to this relay control pin, the electromagnetic coil is turned on, and the armature pushes the normally closed contact to open and the normally open contact to close under the action of the magnetic field, and the USB keyboard data differential signal of machine B and the USB mouse data differential signal of machine B will be output to the second stage.

[0033] The second stage also uses a double-pole double-throw electromagnetic relay to select whether to connect or disconnect the keyboard and mouse data differential signals output by the first stage to the baseboard. Figure 2 As shown, when the MCU GPIO outputs a low level to the relay control pin, the electromagnetic coil is not turned on, the normally closed contact remains closed, the normally open contact remains open, and the keyboard and mouse data differential signals of machine A and machine B will not be output to the baseboard; when the MCU GPIO outputs a high level to the relay control pin, the electromagnetic coil is turned on, and the armature pushes the normally closed contact to open and the normally open contact to close under the action of the magnetic field, and the USB keyboard data differential signal and USB mouse data differential signal of machine A or machine B outputted at the first level will be output to the baseboard.

[0034] Keyboard or mouse USB switching requires simultaneous control of the power-on and power-off timing of the external mouse and keyboard. The microcontroller GPIO generates a control signal to control whether to output the switch board's own 5V and GND to the external USB keyboard and mouse device. A double-pole double-throw electromagnetic relay is used to achieve simultaneous on-off control of 5V and GND, such as Figure 2 As shown in the figure, when the MCU GPIO outputs a low level to the relay control pin, the electromagnetic coil is not turned on, the normally closed contact remains closed, the normally open contact remains disconnected, and the USB 5V and GND will not be output to the baseboard; when the MCU GPIO outputs a high level to the relay control pin, the electromagnetic coil is turned on, and the armature pushes the normally closed contact to open under the action of the magnetic field, and the normally open contact is closed, and the switch board itself will output 5V and GND to the baseboard to power the USB keyboard and mouse devices. In the hardware design, the control of the differential signal and the 5V power supply is separated to simulate the different lengths of the gold fingers inside the USB interface port. When the device is inserted, the outer power line is connected first to power the device, and the middle data line can exchange data in the power-on state; on the contrary, when the device is unplugged, the data transmission is disconnected first to ensure that the data will not be lost due to power failure, and then the power supply of the device is cut off. In this way, it can be ensured that there is no impact on the computer system and USB devices during the plug-in and unplug process to achieve the hot plug function.

[0035] The switching board also leads out three UART signals through a single-chip microcomputer. Two of the RS232 signals are respectively connected to the serial ports of Machine A and Machine B through the bottom board. Machine A and Machine B can query the working status of the switching board and the KVM switching control through the RS232 serial port. In a certain embodiment, the SM3232AE type RS232 transceiver of Shenzhen Guowei Electronics Co., Ltd. is selected to implement the RS232 electrical interface. The third path is a UART serial port signal with a 3.3V TTL level led out through the single-chip microcomputer inside the switching board, which is used for the debugger to query the working status of the switching board and the KVM switching control from the debugging serial port.

[0036] The present invention realizes the following specific switching functions:

[0037] 1) The switching board switches the USB keyboard and mouse control signals through an electromagnetic relay

[0038] 2) The switching board switches the DVI / HDMI video signals through the JMX3845 chip.

[0039] 3) The switching board outputs two LED indicator control signals externally to indicate which main processing board currently has the control of the KVM.

[0040] 4) The switching board has two RS232 serial ports, which are respectively connected to two external main processor boards. The main processor boards can query the current switching status and the KVM control through the serial port.

[0041] 5) The switching board switches according to the current KVM display status by collecting external key signals.

[0042] 6) The switching board has one debugging serial port and two single-chip microcomputer debugging indicator lights. The debugger can query the current switching status and the KVM control through the serial port.

[0043] The switching board is assembled in the display control device and is connected to the front panel switches, buttons, indicator lights, the bottom board, the power board, and the main processor board of the display control device. The system principle block diagram is as Figure 2 shown.

[0044] Embodiment 1:

[0045] The following further illustrates the present invention through a KVM switching board designed with reference to the present design method and already used in a model project, but it is not a limitation to the present invention.

[0046] Specifically, the KVM switching board is applied to a display control device adopting a dual-mainboard redundancy design. Motherboard A and motherboard B realize the role switching between the working machine and the backup machine through buttons or software, and a set of keyboard, mouse, and display need to be multiplexed time-sharing.

[0047] After the device is powered on, it defaults to output the KVM signal of Machine A, and the indicator light A lights up, and the debugging DVI outputs the signal of Machine A. When the button is pressed and released, it switches to the KVM signal of Machine B, and the indicator light B lights up, and the debugging DVI outputs the signal of Machine B. Open the serial port debugging assistant, connect to the UART2 or UART3 channel of the microcontroller, set up the serial port, and send the command 0xAC00 to obtain the current display status as Machine A or Machine B; send the command 0xEEFF to obtain which machine sent the current command; send the command 0x00AA to switch the current display status to the KVM signal of Machine A; send the command 0x00BB to switch the current display status to the KVM signal of Machine B; the same applies to the debugging serial port. The specific control functions and commands are shown in Table 1.

[0048] Table 1 Serial Port Functions and Commands

[0049]

[0050]

[0051] The present invention replaces the keyboard and mouse interface with a USB interface, and through a domestic electromagnetic relay, completes the switching of USB control signals, greatly simplifying the design and reducing costs.

[0052] The domestic JMX3845 chip used in the present invention can realize 2-way DVI / HDMI input and fan out 4-way DVI / HDMI output, providing a video output debugging interface in a dual-mainboard redundant display and control device for debuggers to view the display status of Machine A and Machine B at the same time.

[0053] The present invention obtains DVI / HDMI input signals from two external main processor boards A and B, and through responding to external switching buttons or serial port commands, performs KVM output switching and indication according to the current status. The output interfaces include a DVI / HDMI output interface directly connected to the device, a USB power supply interface, two USB data differential interfaces, and two switching indicator lights that can directly indicate that the current output status is Machine A or Machine B, and a DVI / HDMI debugging output interface and two debugging indicator lights related to debugging. The software and hardware of this system can achieve a 100% localization rate.

[0054] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, without departing from the technical principle of the present invention, several improvements and deformations can still be made, and these improvements and deformations should also be regarded as the protection scope of the present invention.

Claims

1. A domestic KVM switching system, characterized in that, The KVM switching system is a switching board, including: a power module, a main control chip, two EEPROMs, a video signal switching module, a keyboard and mouse signal switching module, and an indicator light module; The power module is responsible for supplying power to the switching system, stepping down the external 12V to 5V and 3.3V. Among them, 5V powers the video signal switching module and external USB keyboard and mouse devices, and 3.3V powers the main control chip; The main control chip is the core component for switching and controlling DVI signals and USB signals from Machine A and Machine B, serial communication, digital input, and LED indicator control; Two EEPROMs are used to store the EDID information of the display. The two EEPROMs are respectively connected to the graphics cards of Machine A and Machine B through the backplane. When Machine A and Machine B are powered on simultaneously, the graphics cards of the two machines read different EEPROMs on the switching board at the same time, and the video output is configured in the format required by the display; The video signal switching module selects a DVI / HDMI 2:4 TMDS interface fan-out buffer chip. The two inputs are DVI input signals from Machine A and Machine B, and the output is two fan-out DVI output signals. One is output to the display control device through the backplane, and the other is directly output from the switching board for debugging. Both outputs can control the switching of DVI signals of Machine A and Machine B; The keyboard and mouse signal switching module is implemented using electromagnetic relays. The differential signal switching of USB mouse and keyboard data is achieved in two levels; the first level uses a double-pole double-throw electromagnetic relay to select one of the differential signals of the USB mouse and keyboard from Machine A or Machine B and outputs it to the second level. The second level also uses a double-pole double-throw electromagnetic relay to select whether to connect or disconnect the keyboard and mouse data differential signals output by the first level to the backplane; for keyboard or mouse USB switching, it is necessary to control the power-on and power-off timing of the external mouse and keyboard simultaneously. The microcontroller GPIO generates a control signal to control whether to output the 5V and GND of the switching board itself to the external USB keyboard and mouse devices, and a double-pole double-throw electromagnetic relay is used to achieve simultaneous on-off control of 5V and GND; The switching board also leads out three UART signals through the microcontroller. Two of them, RS232, are respectively connected to the serial ports of Machine A and Machine B through the backplane. Machine A and Machine B can query the working status of the switching board and KVM switching control through the RS232 serial port; the third is a UART serial port signal with a 3.3V TTL level led out through the microcontroller inside the switching board for the debugger to query the working status of the switching board and KVM switching control from the debugging serial port; The switching board outputs two LED indicator control signals externally to indicate which main processing board currently has control over the KVM. The switching board has one debugging serial port and two microcontroller debugging indicator lights. The debugger queries the current switching status and KVM control through the serial port; the switching board switches according to the current KVM display status by collecting external button signals; 2. The domesticated KVM switching system according to claim 1, wherein The power module selects an HCE4644MB type four-channel 4A output, wide-voltage input DC / DC converter to step down the external 12V to 5V and 3.3V.

3. The domestic KVM switching system according to claim 1, wherein The main control chip selects the CS32F103CB type microprocessor. The CS32F103CB standard series products provide a 48-pin package form, and the code and instructions are completely compatible with the STM32F103CB series digital signal processors.

4. The domesticated KVM switching system according to claim 1, wherein, The EEPROM selects the AiP24C256 type.

5. The domesticated KVM switching system as claimed in claim 1, wherein The buffer chip selects the JMX3845 type, which is compatible with the MAX3845 chip of the American MAXIM company and can withstand the multi-channel video signal distribution of DVI or HDMI signals with a maximum of 1.65 Gbps.

6. The domestic KVM switching system according to claim 1, characterized in that, The electromagnetic relay selects the JRC-089M / 005-02-II type electromagnetic relay.

7. The domesticated KVM switching system according to any one of claims 1-6, characterized in that The first stage uses a double-pole double-throw electromagnetic relay to select one from the differential signals of the USB mouse and keyboard of machine A or machine B and output it to the second stage; when the single-chip microcomputer GPIO outputs a low level to the control pin of this relay, the electromagnetic coil is not conducted, the normally closed contact remains closed, and the normally open contact remains open. The USB keyboard data differential signal of machine A and the USB mouse data differential signal of machine A will be output to the second stage; when the single-chip microcomputer GPIO outputs a high level to the control pin of this relay, the electromagnetic coil is conducted, and under the action of the magnetic field, the armature pushes the normally closed contact to disconnect and the normally open contact to close. The USB keyboard data differential signal of machine B and the USB mouse data differential signal of machine B will be output to the second stage.

8. The domesticated KVM switching system according to claim 7, wherein The second stage uses a double-pole double-throw electromagnetic relay to select whether to connect or disconnect the keyboard and mouse data differential signals output by the first stage to the backplane; when the single-chip microcomputer GPIO outputs a low level to the control pin of this relay, the electromagnetic coil is not conducted, the normally closed contact remains closed, and the normally open contact remains open. The keyboard and mouse data differential signals of machine A and machine B will not be output to the backplane; when the single-chip microcomputer GPIO outputs a high level to the control pin of this relay, the electromagnetic coil is conducted, and under the action of the magnetic field, the armature pushes the normally closed contact to disconnect and the normally open contact to close. The USB keyboard data differential signal and the USB mouse data differential signal of machine A or machine B output by the first stage will be output to the backplane.

9. The domestic KVM switching system according to claim 8, wherein, A double-pole double-throw electromagnetic relay is used to realize the simultaneous on-off control of 5V and GND. When the single-chip microcomputer GPIO outputs a low level to the control pin of this relay, the electromagnetic coil is not conducted, the normally closed contact remains closed, and the normally open contact remains open. The 5V and GND of the USB will not be output to the backplane; when the single-chip microcomputer GPIO outputs a high level to the control pin of this relay, the electromagnetic coil is conducted, and under the action of the magnetic field, the armature pushes the normally closed contact to disconnect and the normally open contact to close. The switching board itself will output 5V and GND to the backplane to supply power to the USB keyboard and mouse devices.

10. The domesticated KVM switching system according to claim 9, wherein, Motherboard A and motherboard B realize the role switching between the working machine and the backup machine through buttons or software, and share a set of keyboard, mouse, and display time-division multiplexing; after the device is powered on, the KVM signal of machine A is output by default, the indicator light A lights up, and the debugging DVI outputs the signal of machine A; when the button is pressed and released, it switches to the KVM signal of machine B, the indicator light B lights up, and the debugging DVI outputs the signal of machine B; Open the serial port debugging assistant, connect to the UART2 or UART3 channel of the microcontroller, set up the serial port, send the command 0xAC00 to obtain the current display status as Machine A or Machine B; send the command 0xEEFF to obtain which machine sent the current command, either Machine A or Machine B; send the command 0x00AA to switch the current display status to the KVM signal of Machine A; send the command 0x00BB to switch the current display status to the KVM signal of Machine B.

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