Tandem type magnetic shaft keyboard control circuit

Abstract

The invention discloses a tandem type magnetic axis keyboard control circuit, which relates to the field of magnetic axis keyboards, and comprises a main control unit MCU and a plurality of key detection driving chips, the second data pin of the Nth key detection driving chip is connected with the first data pin of the (N + 1) th key detection driving chip; a first data pin of the first key detection driving chip is connected with a data pin DT of the main control unit, and a second data pin of the last key detection driving chip is connected with the terminal circuit; the main control unit is used for sending LED brightness adjusting information to the key detection driving chip and receiving Hall detection information from the key detection driving chip; the key detection driving chip is used for detecting triggering of the key, transmitting Hall detection information to the control unit and driving the LED according to the LED brightness adjusting information. Through a series-connection type framework, local digitization and two-way communication with priorities, the defects that a magnetic axis keyboard is complex in wiring, signals are prone to being interfered, and response is not timely are overcome.

Description

Technical Field

[0001] This invention relates to the field of magnetic axis keyboards, and more specifically to a series magnetic axis keyboard control circuit. Background Technology

[0002] As an input device, magnetic axis keyboards have gradually gained market attention due to their advantages such as adjustable key travel, no physical contact, and long lifespan. Their core lies in using linear Hall sensors to detect the linear change of the magnetic field during key presses, thereby achieving accurate key travel measurement and fast response.

[0003] In traditional magnetic axis keyboard implementations, a single main control chip typically manages dozens or even hundreds of Hall effect sensors. Due to the limited number of analog-to-digital converter channels in the main control chip, external multi-channel analog switches are commonly used to expand the sampling channels. This approach requires each Hall effect sensor to be connected to an analog switch via an independent analog signal line, and then selected by the analog switch before being connected to the main control chip's analog-to-digital converter. This connection method results in a large number of traces on the printed circuit board, severe signal line crossings, increased wiring complexity and layer requirements, thereby increasing hardware costs and limiting the application of the product in small-size or low-cost applications.

[0004] Another drawback of the existing technical solution is the reliability of signal transmission. The analog voltage signal output by the Hall sensor needs to be transmitted over a long distance on the printed circuit board, which is very susceptible to electromagnetic interference from other digital circuits on the board or the external environment, resulting in a decrease in signal quality and damage to measurement accuracy. This fragility of analog signal transmission directly affects the accuracy and stability of keyboard key detection.

[0005] In addition, in terms of system communication architecture, the existing solution lacks an efficient data scheduling mechanism. When the keyboard needs to process multiple key trigger signals and complex LED lighting effects at the same time, all data is transmitted on the same link, which can easily lead to resource contention. Without effective priority management, critical key trigger information may be blocked by a large amount of lighting adjustment data, causing key response delay and affecting the smoothness of user experience.

[0006] Therefore, how to design a series magnetic axis keyboard control circuit that simplifies the circuit structure, improves the reliability of signal transmission, and ensures the priority of key response is a problem that urgently needs to be solved by those skilled in the art. Summary of the Invention

[0007] In view of this, the present invention provides a series magnetic axis keyboard control circuit, which aims to overcome the shortcomings of the prior art, such as complex PCB design and high cost caused by the use of multiple analog switches and complex matrix wiring, as well as the susceptibility of analog signal transmission to interference over long distances and the limitation of system response speed.

[0008] To achieve the above objectives, the present invention adopts the following technical solution: A series magnetic axis keyboard control circuit includes a main control unit (MCU) and multiple key detection driver chips; The number of key detection driver chips is the same as the number of keys on the keyboard, and each key detection driver chip includes a first data pin DA and a second data pin DB. The multiple key detection driver chips and the main control unit form a serial communication link. In the serial communication link, the second data pin DB of the Nth key detection driver chip is connected to the first data pin DA of the N+1th key detection driver chip; the first data pin DA of the first key detection driver chip is connected to the data pin DT of the main control unit; and the second data pin DB of the last key detection driver chip is connected to the terminal circuit. The main control unit is used to send LED brightness adjustment information to the button detection driver chip and receive Hall detection information from the button detection driver chip. The button detection driver chip is used to detect button triggering and transmit Hall detection information to the control unit, as well as drive the LED according to the LED brightness adjustment information.

[0009] Preferably, the terminal circuit includes a pull-up resistor, the first end of which is connected to the power supply voltage, and the second end of which is connected to the second data pin DB of the last button detection driver chip.

[0010] Preferably, the serial communication link adopts a bidirectional communication method; Specifically, Hall effect detection information is transmitted step by step from the triggered button detection driver chip to the main control unit; LED brightness adjustment information is transmitted step by step from the main control unit to the target button detection driver chip; and the transmission priority of Hall effect detection information is higher than that of LED brightness adjustment information.

[0011] Preferably, during power-on initialization, the main control unit assigns a unique address information to each key detection driver chip via the serial communication link. Preferably, the Hall effect detection information is transmitted with the address of the button detection driver chip that generates the information, and the LED brightness adjustment information is transmitted with the address of the target button detection driver chip. When each button detection driver chip receives LED brightness adjustment information, it compares the address information in the information with its own address. If they match, the brightness adjustment is performed; otherwise, the information is forwarded to the next stage.

[0012] Preferably, each key detection driver chip includes: a linear Hall sensor, an analog-to-digital converter (ADC), an LED driver circuit, and a communication logic module; The linear Hall sensor is used to generate an analog voltage signal based on changes in the magnetic field. The analog-to-digital converter (ADC) is used to convert the analog voltage signal into digital Hall detection information. The LED driving circuit is used to drive and adjust the LED brightness according to the LED brightness adjustment information; The communication logic module is used to control the data transmission and reception of the first data pin DA and the second data pin DB.

[0013] Preferably, the conversion accuracy of the analog-to-digital converter (ADC) is M bits, and the Hall detection information is compressed to N bits during communication transmission, where N < M.

[0014] Preferably, the communication logic module includes: The first current source and the first switching transistor are used to control the voltage pull-down of the second data pin DB to enable data transmission. The second current source and the second switch are used to control the voltage pull-down of the first data pin DA to achieve forward data transmission; The current value of the second current source is greater than the current value of the first current source.

[0015] Preferably, the communication logic module further includes: A first comparator is used to detect forward-transmitted data from the first data pin DA via a first reference voltage; The second comparator is used to detect backward transmission data from the second data pin DB via the second reference voltage; The third comparator is used to detect the voltage of the second data pin DB by means of a third reference voltage; when the detected voltage is lower than the third reference voltage, it is determined to be a communication conflict and the transmission of data through the second data pin DB is suspended.

[0016] Preferably, each button detection driver chip includes multiple LED driver pins for driving LEDs of different colors respectively, and the target color is mixed by adjusting the PWM duty cycle of each driver pin.

[0017] As can be seen from the above technical solution, compared with the prior art, the technical solution of the present invention has the following beneficial effects: 1. The control circuit adopts a series communication link structure, which allows all key detection driver chips to be cascaded through only one pair of data lines (DA / DB) and connected to the main control unit. With the unified power supply and ground line, a fully parallel or series connection method is formed. This avoids the problem of complex cross-wiring in traditional matrix or analog switch solutions, and makes it possible to use a lower-cost single-layer PCB board, reducing the complexity and cost of hardware wiring.

[0018] 2. Each button detection driver chip integrates an ADC, which converts the Hall analog signal into digital information locally. Combined with bidirectional communication, address allocation and priority mechanism, it realizes that the button trigger information is transmitted to the main control unit in digital form with address identification and high priority. This not only avoids the defects of analog signal being susceptible to interference during long-distance transmission, but also ensures that button actions can be quickly and accurately identified and responded to.

[0019] 3. Its limited data compression and differentiated current drive reduce the amount of data transmitted per unit, alleviating the pressure on bus bandwidth; at the same time, combined with the conflict detection and handling mechanism, it can prioritize the transmission of critical data when communication contention occurs, thus maintaining the stability and reliability of system communication even in complex scenarios with multiple triggers. Attached Figure Description

[0020] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0021] Figure 1 This is a schematic diagram of the control circuit structure of a series magnetic axis keyboard provided in an embodiment of the present invention; Figure 2 This is a schematic diagram of the key detection driver chip provided in an embodiment of the present invention; Figure 3 This is a schematic diagram of the communication module structure provided in an embodiment of the present invention; Figure 4 This is a waveform diagram of a communication node during backward data transmission provided in an embodiment of the present invention; Figure 5 A waveform diagram of a communication node during forward data transmission provided in an embodiment of the present invention; Figure 6 A schematic diagram of a communication module circuit with collision detection provided in an embodiment of the present invention; Figure 7 The node voltage waveform diagram during communication collisions provided in this embodiment of the invention; Figure 8 A schematic diagram of a communication module circuit with collision detection and retransmission provided in an embodiment of the present invention; Figure 9 This is a schematic diagram of the interface circuit of the main control unit MCU provided in an embodiment of the present invention. Detailed Implementation

[0022] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0023] This embodiment provides a series magnetic axis keyboard control circuit, including a main control unit MCU and multiple key detection driver chips; The number of key detection driver chips is the same as the number of keys on the keyboard, and each key detection driver chip includes a first data pin DA and a second data pin DB. Multiple button detection driver chips and the main control unit form a serial communication link; In the serial communication link, the second data pin DB of the Nth key detection driver chip is connected to the first data pin DA of the N+1th key detection driver chip; the first data pin DA of the first key detection driver chip is connected to the data pin DT of the main control unit; and the second data pin DB of the last key detection driver chip is connected to the terminal circuit. like Figure 1 The diagram illustrates the connection between three button detection driver chips and an MCU. The MCU includes at least a power pin (VDD), a ground pin (G), and a data communication pin (DT). Chip1 is the first detection driver chip, Chip2 is the second, and Chip3 is the third. Each detection driver chip drives three LEDs, forming three different color LEDs. Different brightness combinations create a colored light effect. The LEDs are driven by anodizing. The detection driver chips output PWM duty cycle control signals through L1~L3, meaning their PWM duty cycle can be adjusted. The larger the PWM duty cycle, the brighter the driven LED. The brightness of the three LEDs with different brightness levels can be combined arbitrarily to achieve color adjustment. VDD and G are connected to the positive and negative terminals of the battery BAT, which powers the MCU and the detection driver chips. The main control unit is used to send LED brightness adjustment information to the button detection driver chip and receive Hall effect detection information from the button detection driver chip. The button detection driver chip is used to detect button triggering and transmit Hall detection information to the control unit, as well as drive the LED according to the LED brightness adjustment information.

[0024] By adopting a serial communication link and a single-wire bidirectional communication architecture, it simplifies the circuit wiring of multi-key keyboards, making it possible to achieve low-cost single-layer PCB design; by converting Hall analog signals into digital information locally and transmitting them with addresses, it improves the signal anti-interference capability and transmission reliability; at the same time, with the help of communication priority and conflict handling mechanisms, it ensures that key trigger information can be responded to quickly and accurately, thus achieving a comprehensive effect of simplified system structure, enhanced reliability and improved real-time performance.

[0025] The control circuit described above will be further explained in detail below; In this embodiment, the terminal circuit includes a pull-up resistor. The first end of the pull-up resistor is connected to the power supply voltage, and the second end is connected to the second data pin DB of the last button detection driver chip.

[0026] Its purpose is to provide a defined high-level bias for the signal node at the end of the serial communication link. When the node is not actively driven by the internal circuit of the chip, it can be stabilized at the logic high level by a pull-up resistor, effectively preventing noise interference introduced by the floating signal and ensuring the determinism of the logic state. At the same time, the pull-up resistor, together with the current source inside the chip used for data transmission, forms a signal voltage drop network, providing a stable level reference for bidirectional data communication, thereby ensuring the reliability of communication at the end of the link.

[0027] In this embodiment, the serial communication link adopts a bidirectional communication method; wherein, Hall detection information is transmitted from the triggered button detection driver chip to the main control unit step by step; LED brightness adjustment information is transmitted from the main control unit to the target button detection driver chip step by step; and the transmission priority of Hall detection information is higher than the transmission priority of LED brightness adjustment information. This section clarifies the bidirectional communication mode and data transmission rules of the serial communication link, dividing the data flow into two directions: high-priority Hall detection information is transmitted forward and low-priority LED brightness information is transmitted backward. This ensures that the user's critical operations can be interrupted in time and take priority over non-critical status updates, solving the response delay problem from the system scheduling level and improving the real-time interactive experience of the keyboard.

[0028] Furthermore, during power-on initialization, the main control unit assigns a unique address information to each key detection driver chip via the serial communication link; Here, the main control unit allocates addresses by sending instruction sequences containing address data. After receiving the instruction sequence, each key detection driver chip sets the address data in the instruction sequence as its own address, increments or decrements the address data, and then forwards the updated instruction sequence to the downstream chip through its second data pin DB. This addressing scheme allows chips of the same model to be used at any position on the link, simplifying the process of production material preparation, PCB layout, and subsequent maintenance and replacement.

[0029] Furthermore, the Hall effect detection information is transmitted along with the address of the button detection driver chip that generated the information, and the LED brightness adjustment information is transmitted along with the address of the target button detection driver chip. When each button detection driver chip receives LED brightness adjustment information, it compares the address information in the information with its own address. If they match, the brightness adjustment is performed; otherwise, the information is forwarded to the next stage.

[0030] All data transmitted on the link must carry an address identifier. After receiving the data, each chip will perform an address matching operation, acting like an intelligent relay. It only responds to data addressed to itself, while non-address data is forwarded as is. This enables logical point-to-point communication to be built on a single physical link, ensuring accurate delivery of instructions.

[0031] In this embodiment, each button detection driver chip includes: a linear Hall sensor, an analog-to-digital converter (ADC), an LED driver circuit, and a communication logic module; Linear Hall sensors are used to generate analog voltage signals based on changes in magnetic fields; The analog-to-digital converter (ADC) is used to convert the analog voltage signal into digital Hall effect detection information. The ADC has a conversion accuracy of M bits, and the Hall effect detection information is compressed to N bits during communication transmission, where N < M. The ADC uses high bit accuracy (e.g., 12 bits) for sampling to ensure measurement accuracy, but in actual communication transmission, it only truncates or compresses the data to a smaller number of bits. This design achieves an optimized balance between front-end acquisition accuracy and back-end transmission efficiency, meeting the accuracy requirements of key detection and reducing the bandwidth pressure on the serial communication link. The LED driver circuit is used to drive and adjust the LED brightness according to the LED brightness adjustment information. The communication logic module is used to control the data transmission and reception of the first data pin DA and the second data pin DB.

[0032] Furthermore, such as Figure 2As shown, one implementation of the detection driver chip in this embodiment is described, which includes a Hall sensor HS, a voltage regulator LDO, an amplifier AMP, an analog-to-digital converter ADC, a communication module Comm, and an LED driver circuit LDRV. The voltage regulator LDO receives voltage from the battery and generates a stable output voltage VLO to power each module. In one implementation, the output voltage VLO of the LDO is 3.3V or 2.8V. The Hall sensor HS generates an analog voltage based on the change in magnetic field (caused by the movement of the magnet when the button is pressed), and outputs it to the AMP module for amplification. The amplified signal is then output to the analog-to-digital converter ADC to be converted into a digital signal HallD[9:0]. In this embodiment, HallD is 10 bits of data, but it can also be 8 bits or 16 bits. The larger the number of bits, the higher the accuracy. The digital signal HallD[9:0] is sent to the communication module Comm to be serially transmitted to the MCU. Here, the communication module Comm adopts a bidirectional single-wire communication method. The MCU can serially transmit LED brightness and color control information (e.g., 24 bits, with each LED using 8 bits to control brightness) to the detection driver chip. The MCU can receive Hall data from the detection driver chip and can reduce the amount of communication data through data compression algorithms, thereby achieving lower power consumption. When the chip is powered on, the MCU serially writes the address to each detection driver chip in sequence. For example, after the first detection driver chip receives the write address instruction from the MCU, it writes 7-bit address information ADDR[6:0] in its AS module. The first detection driver chip can be written with 0000001, the second detection driver chip can be written with 0000010, the second detection driver chip can be written with 0000011, and so on, until each detection driver chip is written with unique address information. Generally, the number of keyboard keys is at most 108, and 7-bit data can achieve complete non-overlapping. When the detection driver chip detects that a key is pressed, it generates a Hall voltage through the Hall sensor, which is amplified and converted into a digital signal HallD[9:0] by the ADC. The communication module Comm adds 7-bit address data to this data to identify the address information, and then transmits the data forward through the DA signal until the data is sent to the MCU. When routing on the PCB, the detection driver chips corresponding to each key are connected in series in a predetermined order. Therefore, the MCU can determine which key was pressed based on the address information. Furthermore, the chip address information can be set using encryption or other encoding methods. Similarly, when the MCU sends LED brightness information, the chip address information is superimposed after the brightness information, thereby achieving brightness adjustment of the LED at a specific button location. When the LED brightness information is serially transmitted to each chip, each chip, upon receiving the LED brightness adjustment information, first compares the last 7 bits of data (with its own chip address information). If the address information matches, the brightness adjustment information is sent to the LDRV module to adjust the PWM duty cycle of the L1~L3 signals to adjust the LED brightness. If the address comparison does not match, the LED brightness information continues to be transmitted to the subsequent chips via the DB signal.

[0033] like Figure 3 The diagram illustrates one implementation of the communication module Comm in this embodiment. When two adjacent chips are connected in series, the DB terminal of the preceding detection driver chip is connected to the DA terminal of the following detection driver chip. The pull-up function is implemented using a shared resistor Rda (located in the following detection driver chip). When not communicating, the communication node connecting the two chips is pulled up to a high level (equal to the VLO voltage, for example, 3.3V) by the resistor Rda. When the preceding stage transmits data to the following stage, MN2 is intermittently turned on through the Logic module, and its conduction current is determined by the current source I1. The voltage when MN2 is turned on is equal to VLO - I1.Rda, where VLO is the voltage value of the VLO node, I1 is the current value of I1, and Rda is the resistance value of Rda. In this embodiment, VLO is 3.3V, I1 = 100 microamps, and Rda = 10K ohms. When MN2 is turned on, the communication node voltage is equal to 3.3 - 1 = 2.3V. The subsequent detection driver chip detects the data transmitted from the previous stage DB terminal through comparator COM1. The threshold of the comparator is set by the reference voltage VR1, which can be set to VLO - I1.Rda / 2. Here, it can be set to 3.3 - 1 / 2 = 2.8V, such as... Figure 4 As shown, the solid line describes the waveform of the communication node, and the dotted line is the waveform of the reference voltage VR1. When the next stage transmits data to the previous stage, the Logic module controls MN1 to conduct intermittently. Its conduction current is determined by the current source I2. The voltage when it is conducting is equal to VLO-I2.Rda, where VLO is the voltage value of the VLO node, I2 is the current value of I2, and Rda is the resistance value of Rda. In this embodiment, VLO is 3.3V, I2 = 200µA, and Rda = 10K ohms. When MN1 is on, the communication node voltage is 3.3 - 2 = 1.3V. The subsequent detection driver chip detects the data transmitted from the previous stage's DB terminal through comparator COM2. The comparator's threshold is set by the reference voltage VR2, which can be set to VLO - I2 * Rda * 3 / 2, or 3.3 - 1.5 = 1.8V. Figure 5 As shown, the solid line describes the waveform of the communication node, and the dotted line represents the waveform of the reference voltage VR2. A logic signal can be generated by comparing the signals through a comparator. It can be seen that when transmitting signals from the later stage chip to the earlier stage chip, a larger amplitude and a different detection threshold are used. This can avoid the problem of not being able to identify signals when transmitting simultaneously.

[0034] like Figure 6 As shown, to avoid reliability issues when transmitting data forward or backward simultaneously (due to the presence of parasitic capacitance and inductance, signal quality may degrade when transmitting signals bidirectionally at the same time), a comparator COM3 is added. When the detection driver chip detects that the voltage at the DB terminal (connected to the DA terminal of the next stage chip) is lower than the VR3 threshold (i.e., when the output signal of comparator COM3 becomes low), it notifies the Logic module to stop sending signals to the next stage chip, thereby reducing the problem of signal quality degradation when transmitting signals bidirectionally.

[0035] like Figure 7 As shown, the solid line describes the voltage waveform on the communication node when bidirectional data transmission occurs simultaneously, and the dotted line represents the voltage signal of the reference voltage VR3. When the solid line is below 0.8V, the output voltage of comparator COM3 will become low.

[0036] like Figure 8 As shown, a comparator COM4 is further added. When the detection driver chip detects that the voltage at the DA terminal (connected to the DB terminal of the previous stage chip) is lower than the VR3 threshold (i.e., when the output signal of comparator COM3 becomes low), it notifies the Logic module that when a communication conflict occurs, it will repeatedly send the Hall detection information to the previous stage one or more times. This ensures that the Hall detection information can be effectively sent out and guarantees that the Hall detection information has a higher transmission priority.

[0037] like Figure 9The diagram shows one implementation of the MCU in this embodiment, including an LDO, a control circuit CTL, other functional circuits such as Bluetooth communication or USB functions, comparator COM3, comparator COM2, current source I1, and NMOS transistor MN2. The functions of comparator COM3, comparator COM2, current source I1, and NMOS transistor MN2 are the same as those of comparator COM3, comparator COM2, current source I1, and NMOS transistor MN2 in the DB terminal detection and control circuit of the aforementioned Comm module, and will not be described again here.

[0038] The serial magnetic axis keyboard control circuit in this implementation is particularly suitable for keyboard products with high requirements for structural compactness, cost control and real-time response. Its serial architecture allows all chips to be connected through a single link. Combined with localized signal processing, it makes it possible to realize the full keyboard circuit layout using a low-cost single-layer PCB. It is especially beneficial for the design of ultra-thin keyboards, irregularly shaped keyboards or complex products with a large number of keys (such as 108 keys), and solves the problems of complex wiring, multiple layers and high cost of traditional solutions. In practical applications, such as high-end gaming keyboards or high-efficiency office keyboards, this circuit ensures that every keystroke by the user is captured quickly and accurately and reported with priority. Even when the keyboard is undergoing complex dynamic changes in RGB lighting effects, the key trigger information can immediately interrupt the transmission of lighting data due to its high communication priority and go directly to the main control unit, achieving a zero-delay response. This reliable real-time interactive experience, combined with its simplified hardware structure, provides a solution that combines performance and cost advantages for the popularization of magnetic axis keyboards.

[0039] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. For the systems disclosed in the embodiments, since they correspond to the methods disclosed in the embodiments, the descriptions are relatively simple; relevant parts can be referred to the method section.

[0040] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A serial magnetic shaft keyboard control circuit, characterized by comprising: The keyboard comprises a master control unit (MCU) and a plurality of key detection driving chips; The number of the key detection driving chips is the same as the number of the keys of the keyboard, and each key detection driving chip comprises a first data pin (DA) and a second data pin (DB); The plurality of key detection driving chips and the master control unit form a serial communication link; In the serial communication link, the second data pin (DB) of the Nth key detection driving chip is connected to the first data pin (DA) of the (N+1)th key detection driving chip, the first data pin (DA) of the first key detection driving chip is connected to a data pin (DT) of the master control unit, and the second data pin (DB) of the last key detection driving chip is connected to a terminal circuit; The master control unit is configured to send LED brightness adjustment information to the key detection driving chips and receive Hall detection information from the key detection driving chips; The key detection driving chip is configured to detect the triggering of a key and transmit Hall detection information to the master control unit, and drive the LED according to the LED brightness adjustment information.

2. A series magnetic axle keyboard control circuit according to claim 1, wherein, The terminal circuit comprises a pull-up resistor, a first end of the pull-up resistor being connected to a power supply voltage, and a second end of the pull-up resistor being connected to the second data pin (DB) of the last key detection driving chip.

3. The series magnetic axle keyboard control circuit according to claim 1, wherein, The serial communication link adopts a bidirectional communication mode; The Hall detection information is transmitted from the triggered key detection driving chip to the master control unit, and the LED brightness adjustment information is transmitted from the master control unit to the target key detection driving chip; and the transmission priority of the Hall detection information is higher than that of the LED brightness adjustment information.

4. The series magnetic joystick keyboard control circuit according to claim 1, wherein, The master control unit assigns a unique address information to each key detection driving chip during power-on initialization through the serial communication link.

5. The series magnetic joystick keyboard control circuit according to claim 1, wherein, The Hall detection information is attached with the address of the key detection driving chip that generates the information during transmission, and the LED brightness adjustment information is attached with the address of the target key detection driving chip during transmission. Each key detection driving chip compares the address information in the received LED brightness adjustment information with its own address, and executes brightness adjustment if the addresses match, otherwise forwards the information to the next stage.

6. The series magnetic joystick keyboard control circuit according to claim 1, wherein, Each key detection driving chip comprises a linear Hall sensor, an analog-to-digital converter (ADC), an LED driving circuit, and a communication logic module; The linear Hall sensor is configured to generate an analog voltage signal according to a magnetic field change; The analog-to-digital converter (ADC) is configured to convert the analog voltage signal into digital Hall detection information; The LED driving circuit is configured to drive and adjust the brightness of the LED according to the LED brightness adjustment information; The communication logic module is configured to control the data transmission and reception of the first data pin (DA) and the second data pin (DB).

7. A series magnetic axle keyboard control circuit according to claim 6, wherein, The conversion accuracy of the analog-to-digital converter (ADC) is M bits, and the Hall detection information is compressed to N bits during communication transmission, where N 8. The series magnetic joystick keyboard control circuit according to claim 6, wherein, The communication logic module comprises: A first current source and a first switch tube for controlling the voltage pull-down of the second data pin (DB) to realize backward data transmission; A second current source and a second switch tube for controlling the voltage pull-down of the first data pin (DA) to realize forward data transmission; The second current source has a current value greater than the first current source.

9. The series magnetic joystick keyboard control circuit according to claim 6, wherein, The communication logic module further comprises: A first comparator for detecting forward transmission data from a first data pin DA by a first reference voltage; A second comparator for detecting backward transmission data from a second data pin DB by a second reference voltage; A third comparator for detecting a voltage of the second data pin DB by a third reference voltage; when detecting that the voltage is lower than the third reference voltage, determining that there is a communication conflict, and pausing backward transmission data through the second data pin DB.

10. The series magnetic joystick keyboard control circuit according to claim 1, wherein, Each key detection driving chip comprises a plurality of LED driving pins for driving LEDs of different colors respectively, and a target color is mixed by adjusting the PWM duty cycle of each driving pin.

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