Serial communication method, serial communication system and backlight system

Abstract

The embodiment of the invention discloses a serial communication method, a serial communication system and a backlight system, the serial communication method adopts a mode of not carrying out address initialization to carry out communication, the technical problem that all subsequent communication is influenced after the address initialization fails in the prior art is solved, and moreover, the communication efficiency is improved. The lengths of the data acquired by the slaves can be inconsistent, so that the method is suitable for application occasions where data with different lengths need to be transmitted to the slaves.

Description

Technical Field

[0001] The present invention relates to the field of power electronics, and more particularly to a serial communication method, a serial communication system and a backlight system. Background Art

[0002] A serial communication system consists of a host and multiple slaves coupled in series. Because these slaves are identical devices, existing technologies typically address each slave by initializing its address to distinguish between slaves at different locations along the communication link. Each slave then has a unique address. The host and slaves then communicate based on the addresses generated by this initialization.

[0003] However, if communication is disturbed during address initialization, address initialization will fail. After address initialization fails, all subsequent communications will be affected. Summary of the Invention

[0004] In view of this, the present invention proposes a serial communication method, a serial communication system and a backlight system to solve the technical problem in the prior art that all subsequent communications will be affected after address initialization fails.

[0005] An embodiment of the present invention provides a serial communication method, which is applied to a serial communication system. The serial communication system includes a host and at least one communication link coupled in series, wherein the communication link includes multiple slaves coupled in series in sequence. The serial communication method includes: the host sends a calibration instruction data packet; the current slave in the communication link is in a first mode to receive the calibration instruction data packet sent by the host or a previous slave and forward it to the next slave; the current slave is controlled to be in a second mode to short-circuit its own input port and output port to form a first path; when the calibration instruction data packet indicates that it needs to calibrate data, the current slave generates a check code based on at least part of the data in its own register list to calibrate the data in the register and generate a calibration result; when the calibration result is a preset calibration result, the current slave sets the level of its own first path to a first level for indicating the preset calibration result, so that the host receives a feedback signal indicating whether the calibration result of the slave in the communication link is the preset calibration result.

[0006] In one embodiment, the current slave generates a check code based on at least part of the data in the register list and a preset algorithm; compares the check code with a reference check code to generate a proofreading result; when the proofreading result is a preset proofreading result, the current slave sets the level of its first path to a first level used to represent the preset proofreading result.

[0007] In one embodiment, the proofreading instruction data packet includes a plurality of proofreading sub-data packets arranged in sequence, and each slave machine that needs to be proofread corresponds to a different proofreading sub-data packet; the current slave machine receives the proofreading instruction data packet sent by the host machine or the previous slave machine to obtain the proofreading sub-data packet corresponding to itself, and sends all the data after the corresponding proofreading sub-data packet in the proofreading instruction data packet to the next slave machine.

[0008] In one embodiment, the check sub-data packet includes a reference check code, so that the current slave obtains the reference check code from its corresponding check sub-data packet.

[0009] In one embodiment, the current slave generates a check code according to data at a preset position in the register list.

[0010] In one embodiment, the check sub-data packet further includes a register address portion; the current slave determines the corresponding position in the register list based on the data of the register address portion, and generates a check code based on the data of the corresponding position in the register list.

[0011] In one embodiment, before the host sends the calibration instruction data packet, the host generates a reference check code corresponding to each slave, and writes the reference check code corresponding to the current slave into a register corresponding to the current slave for storage.

[0012] In one embodiment, when the current slave determines that the check code is inconsistent with the reference check code, the check result is a preset check result, and the potential of the first path thereof is set to a first level.

[0013] In one embodiment, within a preset time threshold, when the potential of a first path in a slave is set to a first level, the potential of a link path formed by coupling multiple first paths in series in the communication link is set to the first level, so that the host receives the first level as a first feedback signal indicating that a calibration result in a slave of the communication link is a preset calibration result.

[0014] In one embodiment, within a preset time threshold, when the first paths in all slaves are not set to the first level, the potential of the link path formed by coupling multiple first paths in all slaves in series is maintained at a second level, so that the host receives the second level as a second feedback signal indicating that there is no slave in the communication link whose calibration result is the preset calibration result.

[0015] In one embodiment, a first slave whose own potential of the first path is set to the first level, before verifying its own data, an initial value of the potential of a link path formed by serially coupling multiple first paths present in the communication link is set to the second level, and the potential of the first path in the slave is set to the second level.

[0016] In one embodiment, each slave further includes a control unit. When the slave is in a first mode, the input port of the slave is coupled to its output port through the control unit. When the slave is in a second mode, the input port and output port of the slave are short-circuited.

[0017] In one embodiment, when the serial communication system operates in the communication mode, the slave device always operates in the first mode.

[0018] In one embodiment, when the serial communication system operates in the calibration mode, the slave first operates in the first mode to transmit the calibration instruction data packet it receives to the next slave directly or after modification, and then the slave is controlled to operate in the second mode.

[0019] In one embodiment, the serial communication system further includes a pull-up circuit configured to set an initial value of the potential of a link path formed by serially coupling a plurality of first paths present in the communication link to a high level as the second level within a preset time threshold, and the first level is configured to be a low level.

[0020] In one embodiment, each slave includes a pull-down unit coupled between any node in its own first path and the ground potential. If the slave determines that its own proofreading result is a preset proofreading result, the pull-down unit is controlled to pull down the potential of its own first path to a low level as the first level, so that the potential of the link path is pulled down from a high level to a low level.

[0021] In one embodiment, the serial communication system further includes a pull-down circuit, which is configured to set an initial value of the potential of a link path formed by serially coupling a plurality of first paths present in the communication link to a low level as a second level within a preset time threshold, and the first level is configured to be a high level.

[0022] In one embodiment, each slave device includes a pull-up unit coupled between any node in its own first path and a power supply. If the slave device determines that its own proofreading result is a preset proofreading result, the pull-up unit is controlled to pull up the potential of its own first path to a high level as the first level, so that the potential of the link path is pulled up from a low level to a high level.

[0023] In one embodiment, the slave includes a mode selection circuit and a control unit, one end of the mode selection circuit is coupled to the input port of the slave, the other end of the mode selection circuit is selectively coupled to the slave output port and the first end of the control unit, and the second end of the control unit is coupled to the slave output port; wherein the mode selection circuit is configured to be controlled by the control unit to control the slave to operate in the first mode or the second mode.

[0024] In one embodiment, the slave includes a mode selection circuit and a control unit, one end of the mode selection circuit is coupled to the output port of the slave, the other end of the mode selection circuit is selectively coupled to the input port of the slave and the first end of the control unit, and the second end of the control unit is coupled to the input port of the slave; wherein the mode selection circuit is configured to be controlled by the control unit to control the slave to operate in the first mode or the second mode.

[0025] In one embodiment, the host includes an input / output multiplexing port configured to send the calibration instruction data packet and receive the feedback signal.

[0026] In one embodiment, the host includes: an output port configured to send out the calibration instruction data packet; an input port configured to receive the feedback signal from the slave; wherein the input port and the output port of the host are both coupled to the input port of the first slave, and after the host sends out the calibration instruction data packet, the output port is set to a high-impedance state.

[0027] In one embodiment, the serial communication method further includes: the host sends a write instruction data packet, the write instruction data packet includes a plurality of write sub-data packets arranged in sequence, and each slave device that needs to write data corresponds to a different write sub-data packet; the current slave device in the communication link receives the write instruction data packet sent by the host or the previous slave device, obtains the data of the first predetermined length in the received write instruction data packet to obtain the write sub-data packet corresponding to the current slave device, and sends all the data after the first predetermined length of the received write instruction data packet to the next slave device; wherein, the predetermined length is determined by the data length information represented by at least one data bit in the corresponding write sub-data packet.

[0028] In one embodiment, the write sub-data packet includes a communication data portion, and one or more identification bits are set before the communication data portion to identify the data length information of the write sub-data packet.

[0029] In one embodiment, the write sub-data packet includes a command portion, which is provided before the communication data portion. One or more identification bits are provided in the command portion to identify the data length information.

[0030] In one embodiment, the write sub-data packet includes a register address portion, the register address portion is set before the communication data portion, and one or more identification bits are set in the register address portion to identify the data length information.

[0031] In one embodiment, the write sub-data packet includes a command part and a register address part, and the command part and the register address part are both set before the communication data part, and one or more identification bits are set in the command part and the register address part respectively to identify the data length information.

[0032] In one embodiment, the write sub-data packet includes a communication data portion and a register address portion, the register address portion is arranged before the communication data portion, and the data length information is determined according to the data of the register address portion.

[0033] In one embodiment, a mapping relationship between the data of the register address portion and the data length information of the written sub-data packet is preset in the slave device, so as to determine the data length information according to the data of the register address portion.

[0034] An embodiment of the present invention also provides a serial communication system, comprising: a host coupled in series and at least one communication link, wherein the communication link comprises a plurality of slaves coupled in series in sequence, each slave comprising an input port and an output port, wherein communication is performed using any of the serial communication methods described above.

[0035] An embodiment of the present invention further provides a serial communication system, comprising: the serial communication system described above, wherein each slave device is used to control a corresponding LED area in a backlight system.

[0036] Compared with the prior art, the technical solution of the present invention has the following advantages: On the one hand, the present invention proposes a first serial communication method that uses a method for communication without address initialization, thereby resolving the technical problem in the prior art that all subsequent communications will be affected if address initialization fails. In addition, the lengths of data obtained by each slave can be inconsistent, thereby being suitable for applications where data of different lengths needs to be transmitted to each slave. On the other hand, the present invention proposes a second serial communication method that feeds back the proofreading results to the host by multiplexing the forward communication channel of the serial communication system, thereby not only completing the host's readback of the information in the slave, but also completing the data proofreading process in the slave, eliminating the need to transmit the relevant data in the slave back to the host so that the host can determine whether the readback data is consistent with the data written by itself, thereby eliminating the need for the host to perform data parsing and proofreading, thereby saving host resources. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] The above and other objects, features and advantages of the present invention will become more apparent through the following description of the embodiments of the present invention with reference to the accompanying drawings, in which:

[0038] Figure 1 A schematic diagram of a communication method in the prior art that does not require address initialization;

[0039] Figure 2 Schematic diagram of a serial communication system according to a first embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of a write instruction data packet received by an input port of each slave device according to a first embodiment of the present invention;

[0041] Figure 4 This is a schematic diagram of coding for writing sub-data packets according to the first embodiment of the present invention;

[0042] Figure 5 Schematic diagram of a second embodiment of a serial communication system of the present invention;

[0043] Figure 6 FIG. 1 is a schematic diagram of a third embodiment of a serial communication system according to the present invention. DETAILED DESCRIPTION

[0044] The present invention is described below based on the following embodiments, but the present invention is not limited to these embodiments. In the detailed description of the present invention below, certain specific details are described in detail. Those skilled in the art can fully understand the present invention without these details. To avoid obscuring the essence of the present invention, well-known methods, processes, procedures, components, and circuits are not described in detail.

[0045] Furthermore, persons of ordinary skill in the art will appreciate that the figures provided herein are for illustration purposes only and are not necessarily drawn to scale.

[0046] At the same time, it should be understood that in the following description, "circuit" refers to a conductive loop composed of at least one element or subcircuit connected electrically or electromagnetically. When an element or circuit is said to be "connected to" another element or an element / circuit is said to be "connected" between two nodes, it can be directly coupled or connected to the other element or there can be intermediate elements. The connection between the elements can be physical, logical, or a combination thereof. Conversely, when an element is said to be "directly coupled to" or "directly connected to" another element, it means that there are no intermediate elements between the two.

[0047] Unless the context clearly requires otherwise, throughout the specification and claims, the words "include," "comprising," and similar words should be construed in an inclusive sense rather than an exclusive or exhaustive sense; that is, in the sense of "including but not limited to."

[0048] In the description of the present invention, it should be understood that the terms "first", "second", etc. are used for descriptive purposes only and should not be understood to indicate or imply relative importance. In addition, in the description of the present invention, unless otherwise specified, "plurality" means two or more.

[0049] In order to solve the technical problem in the prior art that all subsequent communications will be affected after address initialization fails, communication can be performed without performing address initialization. Figure 1 This is a communication method in the prior art that does not require initialization of addresses. Figure 1 As shown, the host packages the data required by multiple slaves in sequence and sends them all at once. After the first slave obtains the corresponding data 1010, it transmits the subsequent data to the second slave. After the second slave obtains the corresponding data 1001, it transmits the subsequent data to the third slave, and so on. However, in this communication method, the slaves can only obtain data of a fixed length at a time. For example, each slave is preset to obtain 24 bits or 8 bytes of data, that is, the length of the data obtained by each slave is consistent. Therefore, in applications where the host needs to transmit data of different lengths to each slave, this communication solution is no longer applicable. Therefore, a first aspect of the present invention provides a serial communication method in which each slave can obtain data of different lengths.

[0050] Figure 2 FIG. 1 is a schematic diagram of a serial communication system embodiment 1 of the present invention; FIG. Figure 2As shown, the serial communication system includes a serially coupled host Master and at least one communication link (one in this embodiment). The communication link includes n slaves IC1 to ICn coupled in series, where n is greater than or equal to 1. Each slave includes an input port SDI and an output port SDO. The input port SDI of the first slave IC1 is coupled to the output port MDO of the host Master, and the input ports SDI of the second slave IC2 to the nth slave ICn are coupled to the output port SDO of the previous slave. Each slave includes a control unit, which is configured to forward or process data packets received by the slave, wherein the processing includes modifying relevant data in the received data packets. In this embodiment, the host Master and the n slaves in the communication link are connected in series via a daisy chain, but the present invention is not limited to this.

[0051] A first serial communication method of the present invention comprises:

[0052] The host sends a write instruction data packet, which includes a plurality of write sub-data packets arranged in sequence, and each slave device that needs to write data corresponds to a different write sub-data packet;

[0053] The current slave in the communication link receives a write instruction data packet sent by the master or the previous slave, obtains the data before the predetermined length in the received write instruction data packet to obtain a write sub-data packet corresponding to the current slave, and sends all the data after the data before the predetermined length in the received write instruction data packet to the next slave;

[0054] The predetermined length is determined by data length information represented by at least one data bit written into the corresponding sub-data packet.

[0055] Furthermore, based on the data length information representing the data length of the corresponding write sub-data packet in the corresponding write sub-data packet, the data of the first predetermined length in the write instruction data packet is obtained, and the predetermined length is configured as the data length represented by the data length information in the corresponding write sub-data packet.

[0056] In one embodiment, the first m slaves need to write data, where m is less than n. In this case, the number of write sub-data packets is m, i.e., the number of write sub-data packets is less than the number of slaves, and each of the first m slaves corresponds to a different write sub-data packet. In another embodiment, all n slaves need to write data, and the number of write sub-data packets is greater than or equal to the number of slaves, and each slave corresponds to a different write sub-data packet.

[0057] In one embodiment, the current slave obtains the write sub-data packet corresponding to the current slave, and stores all or part of the write sub-data packet corresponding to the current slave.

[0058] Figure 3 Schematic diagram of a write instruction data packet received by the input port of each slave according to the first embodiment of the present invention; specifically, Figure 3 A schematic diagram of the write instruction data packets received by the input ports of the first four slaves is given in Example 1 when the number of slaves is greater than or equal to 4, that is, n is greater than or equal to 4, and the slaves to which data need to be written are the first four slaves. Figure 3As shown, the host sends a write command data packet, which includes four sequentially arranged write sub-data packets A1-A4. The data lengths of write sub-data packets A1-A4 are different, and each write sub-data packet corresponds to a slave. The first slave IC1 receives the write command data packet sent by the host. In this case, the write command data packet includes sequentially arranged write sub-data packets A1-A4. Based on the data length information in write sub-data packet A1 indicating the data length of write sub-data packet A1, the first slave IC1 obtains the data before the predetermined length in the received write command data packet, that is, obtains write sub-data packet A1. In this case, the predetermined length is configured as the data length indicated by the data length information in write sub-data packet A1. The first slave IC1 then sends all the data after the predetermined length in the received write command data packet (i.e., write sub-data packets A2-A4) to the second slave IC2. The second slave IC2 receives the write instruction data packet sent by the first slave IC1. At this time, the write instruction data packet includes write sub-data packets A2 to A4 arranged in sequence. The second slave IC2 obtains the data of the first predetermined length in the received write instruction data packet based on the data length information in the write sub-data packet A2 that represents the data length of the write sub-data packet A2, that is, obtains the write sub-data packet A2. At this time, the predetermined length is configured as the data length represented by the data length information in the write sub-data packet A2, and sends all the data after the first predetermined length of the data in the received write instruction data packet (that is, write sub-data packets A3 to A4) to the third slave IC3. The third slave IC3 receives a write instruction packet from the second slave IC2, which includes write sub-packets A3 and A4. Based on the data length information in write sub-packet A3 indicating the data length of write sub-packet A3, the third slave IC3 retrieves the data preceding the predetermined length from the received write instruction packet, i.e., retrieves write sub-packet A3. In this case, the predetermined length is configured as the data length indicated by the data length information in write sub-packet A3. The third slave IC3 then sends all the data following the predetermined length from the received write instruction packet (i.e., write sub-packet A4) to the fourth slave IC4. The fourth slave IC4 receives a write instruction packet from the third slave IC3, which includes write sub-packet A4. Based on the data length information in write sub-packet A4 indicating the data length of write sub-packet A4, the fourth slave IC4 retrieves the data preceding the predetermined length from the received write instruction packet, i.e., retrieves write sub-packet A4. In this case, the predetermined length is configured as the data length indicated by the data length information in write sub-packet A4.

[0059] Figure 4 This is a schematic diagram of coding for writing sub-data packets according to the first embodiment of the present invention. Figure 4, to illustrate two solutions for setting the data length information written into the sub-data packet provided by the present invention, but the present invention is not limited thereto.

[0060] In the first solution, a write sub-data packet includes a communication data portion (Data), with one or more flags set before the communication data portion (Data) to indicate the data length of the write sub-data packet. The data in the communication data portion (Data) is configured as data to be written to the corresponding slave. Optionally, the slave performs corresponding actions based on the data in the communication data portion (Data).

[0061] In one embodiment, Figure 4 As shown, the write sub-data packet includes a command portion, Command, which is set before the communication data portion, Data. One or more identification bits are set in the command portion to identify the data length information. The data in the command portion is used to distinguish different commands, such as a write command, a read command, or a verify command.

[0062] In another embodiment, Figure 4 As shown, the write sub-data packet includes a register address portion Register, which is set before the communication data portion Data. One or more identification bits are set in the register address portion Register to identify the data length information. The data in the register address portion Register is used to represent the address of the register to which the data in the communication data portion Data is written.

[0063] In another embodiment, Figure 4 As shown, the write sub-data packet includes a command part Command and a register address part Register, and the command part Command and the register address Register part are both set before the communication data part Data, and one or more identification bits are set in the register address part Register and the command part Command respectively to identify the data length information.

[0064] A second solution involves writing a sub-data packet including a communication data portion (Data) and a register address portion (Register). The register address portion (Register) is provided before the communication data portion (Data). The data length information is determined based on the data in the register address portion (Register). Specifically, a mapping relationship between the data in the register address portion (Register) and the data length information of the write sub-data packet is preset within the slave device, so that the data length information is determined based on the data in the register address portion (Register).

[0065] It should be noted that in Figure 4 In the coding diagram shown, each write sub-data packet includes a command portion, a register address portion, and a communication data portion, but the present invention is not limited to this. For example, in one embodiment, each write sub-data packet includes a command portion and a communication data portion. In another embodiment, each write sub-data packet includes a register address portion and a communication data portion. In another embodiment, each write sub-data packet includes a communication data portion and other portions, and the other portions are arranged before the communication data portion. It is sufficient to achieve the technical effect of setting one or more identification bits before the communication data portion Data to identify the data length information of the write sub-data packet.

[0066] In this embodiment, the output port SDO of the last slave is not coupled to the master Master, but the present invention is not limited to this. In the embodiment where the output port SDO of the last slave is coupled to the master Master, the first serial communication method mentioned above can also be used for communication.

[0067] Existing technology and Figure 2 The output port of the last slave in the communication is not coupled to the host. Therefore, the host cannot obtain information from the slave, that is, the host cannot read back the information from the slave, and thus the host cannot verify the information in the slave. A second aspect of the present invention provides a serial communication method for a host to obtain information from a slave. Specifically, by multiplexing the forward communication channel of the serial communication system and feeding back the verification result to the host, not only the host can read back the information in the slave, but also the data verification is completed in the slave. There is no need to transmit the relevant data in the slave back to the host so that the host can determine whether the read-back data is consistent with the data written by the host. Therefore, the host does not need to perform data parsing and verification, which saves host resources.

[0068] Figure 5 A schematic diagram of a second embodiment of the serial communication system of the present invention is given, as shown in FIG. Figure 5 As shown, in this embodiment, the serial communication system includes a host Master and at least one communication link ( Figure 51 in the figure), the communication link includes n slaves IC1~ICn coupled in series in sequence, where n is greater than or equal to 1. Each slave includes an input port SDI and an output port SDO. The input port SDI of the first slave IC1 is coupled to the input and output multiplexing port MDO / MDI of the master Master; the input port SDI of the second slave IC2 to the nth slave ICn is respectively connected to the output port SDO of the previous slave. Each slave includes a control unit 11, which is configured to forward the data packet received by the slave, or forward it after processing, and the processing includes modifying the relevant data in the data packet. In this embodiment, the master Master and the n slaves in the communication link are connected in series via a daisy chain, but the present invention is not limited to this.

[0069] In this embodiment, when the serial communication system operates in a communication mode (including a write mode), a master and multiple slaves communicate serially. The master sends a data packet (e.g., a write instruction packet) to the slave. The slave operates in a first mode, in which the slave's input port SDI is coupled to its output port SDO via the control unit 11. When the serial communication system operates in a calibration mode, the master sends a calibration instruction packet. The slave first operates in the first mode. The slave's input port SDI transmits the received calibration instruction packet to its output port SDO via the control unit 11, thereby transmitting the calibration instruction packet to the next slave. The slave is then controlled to operate in a second mode. In this mode, the slave's input port SDI and output port SDO are short-circuited, i.e., the input port SDI and output port SDO are directly connected. When the calibration instruction packet indicates that the slave itself needs to perform calibration, the slave performs data calibration to generate a calibration result. The slave then transmits a feedback signal to the master indicating whether its calibration result is a preset calibration result.

[0070] Specifically, when the serial communication system operates in the calibration mode, a second serial communication method is used to feed back a feedback signal indicating whether a calibration result corresponding to a preset calibration result exists in a slave in the communication link to the master. The second serial communication method includes:

[0071] The host Master sends a calibration instruction data packet;

[0072] The current slave in the communication link is in the first mode to receive the calibration instruction data packet sent by the master or the previous slave and forward it to the next slave;

[0073] The slave is currently controlled to be in the second mode to short-circuit its own input port SDI and output port SDO to form a first path;

[0074] When the check instruction data packet indicates that the slave needs to check data, the slave generates a check code based on at least part of the data in its register list to check the data in the register and generate a check result;

[0075] When the proofreading result is the preset proofreading result, the current slave sets the level of its first channel to the first level used to represent the preset proofreading result, so that the host Master receives a feedback signal indicating whether the proofreading result of the slave in the communication link is the preset proofreading result.

[0076] In one embodiment, the current slave generates a check code based on at least part of the data in the register list and a preset algorithm; compares the check code with a reference check code to generate a proofreading result; when the proofreading result is a preset proofreading result, the current slave sets the level of its first path to a first level used to represent the preset proofreading result.

[0077] In the first embodiment, the encoding method of the proofreading instruction data packet and the transmission method in the serial communication system are different from those in the first embodiment. Specifically, in this embodiment, when the current slave is in the first mode, it receives the proofreading instruction data packet sent by the host Master or the previous slave and forwards it to the next slave. During this process, the current slave does not change (for example, reduce) the data length of the proofreading instruction data packet, so that the data length of the proofreading instruction data packet received by each slave is the same. Optionally, the proofreading instruction data packet includes a command portion, a device address portion, a register address portion, and a communication data portion. The data in the device address portion is used to represent the address of the target slave that needs to be proofread this time. When there is only one target slave that needs to be proofread at a time, the data in the communication data portion is the data corresponding to the target slave. When there are multiple target slaves that need to be proofread at a time, the data in the communication data portion is the data corresponding to multiple target slaves. Optionally, when there are multiple target slaves that need to be proofread at a time, the proofreading instruction data packet may not include the device address portion.

[0078] In the second embodiment, the encoding method of the proofreading instruction data packet and the transmission method in the serial communication system are similar to those in the first embodiment, that is, the proofreading instruction data packet includes a plurality of proofreading sub-data packets arranged in sequence, each slave that needs to be proofread corresponds to a different proofreading sub-data packet, the current slave receives the proofreading instruction data packet sent by the host or the previous slave to obtain its own corresponding proofreading sub-data packet, and sends all the data after the corresponding proofreading sub-data packet in the proofreading instruction data packet to the next slave. Optionally, the encoding and Figure 4Similarly, it includes a command part, a register address part, and a communication data part. In this embodiment, when the current slave is in the first mode, it receives a proofreading instruction data packet sent by the host Master or the previous slave, and forwards it to the next slave. In this process, the current slave intercepts the data before the first length in the proofreading instruction data packet, and forwards the data after the data before the first length in the proofreading instruction data packet to the next slave, so that the data length of the proofreading instruction data packet received by the next slave is less than the data length of the proofreading instruction data packet received by the previous slave. In order to be consistent with the encoding method of the write instruction data packet in Example 1 and its transmission method in the serial communication system, the encoding method of the above-mentioned second embodiment is used as an example for explanation, but the present invention is not limited to this.

[0079] In one embodiment, the current slave generates a check code based on data at a preset position in the register list. Specifically, the check sub-data packet also includes a register address portion. The current slave determines the corresponding position in the register list based on the data in the register address portion, and generates a check code based on the data at the corresponding position in the register list. Optionally, the check code is generated based on all the data in the register list. Optionally, the check code is generated based on data at a preset portion of the register list.

[0080] Furthermore, there are multiple ways for the slave to obtain the reference check code. In one embodiment, the proofreading sub-data packet includes a reference check code, so that the current slave obtains the reference check code from its own corresponding proofreading sub-data packet. Optionally, the reference check code is placed in the communication data portion of the proofreading sub-data packet. In another embodiment, before the host sends the proofreading instruction data packet, the host generates a reference check code corresponding to each slave, and writes the reference check code corresponding to the current slave into the register corresponding to the current slave for storage, so that the current slave obtains the reference check code from its own corresponding register.

[0081] In one embodiment, when the current slave determines that the check code and the reference check code are inconsistent, the proofreading result is determined to be a preset proofreading result, and the potential of the first path of the current slave is set to the first level. This method will be used as an example for explanation below, but the present invention is not limited to this. For example, in another embodiment, when the current slave determines that the check code and the reference check code are consistent, the proofreading result is determined to be a preset proofreading result, and the potential of the first path of the current slave is set to the first level. It should be noted that when the check code and the reference check code are inconsistent, it means that the actual data in the slave is inconsistent with the data written by the host or the data stored in the slave as the host believes. If there is a check code in a slave in the communication link that is inconsistent with the reference check code, the host needs to perform corresponding processing, such as rewriting data, shutting down and restarting, etc., so that the data actually stored in the corresponding registers of each slave is consistent with the data stored in the corresponding registers of the slave as the host believes.

[0082] Furthermore, within a preset time threshold, if the potential of the first path in a slave is set to the first level, the potential of the link path formed by the serial coupling of multiple first paths in the communication link is set to the first level, so that the master receives the first level as a first feedback signal indicating that the verification result of the slave in the communication link is the preset verification result. Within the preset time threshold, if the first paths in all slaves are not set to the first level, the potential of the link path formed by the serial coupling of multiple first paths in all slaves remains at a second level, so that the master receives the second level as a second feedback signal indicating that the verification result of the slave in the communication link is the preset verification result.

[0083] For a first slave whose first channel potential is set to the first level, before verifying its own data, the initial value of the potential of a link channel formed by serially coupling multiple first channels in the communication link is set to the second level, thereby setting the potential of the first channel in the slave to the second level. When the first slave whose first channel potential is set to the first level determines that the verification result is the preset verification result, the potential of the first channel in the first slave whose first channel potential is set to the first level changes, i.e., jumps from the second level to the first level. When the second and subsequent slaves whose first channel potential is set to the first level determine that the verification result is the preset verification result, the potential of the first channel in the second and subsequent slaves whose first channel potential is set to the first level no longer changes, i.e., remains at the first level.

[0084] For example, the slave whose potential of the first channel is set to the first level is the i-th slave. The i-th slave operates in the first mode to receive the calibration instruction data packet sent by the i-1-th slave and forwards it to the i+1-th slave.

[0085] The i-th slave is then controlled to operate in the second mode to short-circuit its input port SDI and output port SDO to form a first path. At this time, since the link path formed by the first paths of the first slave to the i-th slave are serially coupled is set to the second level, the potential of the first path in the i-th slave is also set to the second level.

[0086] If the i-th slave indicates that it needs to proofread data according to the proofreading instruction data packet, the i-th slave generates a check code based on at least part of the data in its own register list to proofread the data in the register and generate a proofreading result. Moreover, when it is judged that the proofreading result is a preset proofreading result, the i-th slave sets the potential of its own first path to the first level, that is, jumps from the second level to the first level, and the potential of the link path formed by the first paths in the 1st to the i-th slaves coupled in series is set to the first level. The host Master receives the first level as a first feedback signal indicating that the proofreading result of the slave in the communication link is the preset proofreading result. At this point, the master has received a first feedback signal indicating that a slave in the communication link has a proofreading result that is the preset proofreading result. In one embodiment, the process of transmitting the proofreading instruction data packet, performing data proofreading, and determining whether its own proofreading result is the preset proofreading result continues. That is, the i+1th slave receives the proofreading instruction data packet and continues to transmit it to the i+2th slave. The i+1th slave also performs data proofreading and determines whether its own proofreading result is the preset proofreading result. However, the subsequent determinations of the i+1th to nth slaves do not affect the feedback signal, and the present invention is not limited to this. For example, in another embodiment, the process of transmitting the proofreading instruction data packet and / or performing data proofreading and determining whether its own proofreading result is the preset proofreading result does not continue after the i-th slave sets the potential of the link path to the first level.

[0087] Each slave device further includes a mode selection circuit 12, one terminal of which is coupled to one of the slave device's input port SDI and output port SDO, and another terminal of which is selectively coupled to the other of the slave device's input port SDI and output port SDO or to a first terminal of a control unit 11. A second terminal of the control unit 11 is coupled to the other of the slave device's input port and output port. Mode selection circuit 12 is configured to be controlled by control unit 11 to control the slave device to operate in either the first mode or the second mode. When the serial communication system operates in the proofreading mode, the host sends a proofreading instruction data packet, the control unit 11 controls the mode selection circuit 12 so that the other end of the mode selection circuit 12 is coupled to the first end of the control unit 11, and the slave operates in the first mode. At this time, the proofreading instruction data packet received by the slave input port SDI is transmitted to the output port SDO through the control unit 11 to transmit the proofreading instruction data packet to the next slave. Thereafter, the control unit 11 controls the mode selection circuit 12 so that the other end of the mode selection circuit 12 is coupled to the other of the input port SDI and the output port SDO of the slave, and the slave is controlled to operate in the second mode. At this time, the input port SDI and the output port SDO of the slave are short-circuited, so that the slave feeds back a feedback signal to the host Master indicating whether its own proofreading result is the preset proofreading result.

[0088] Specifically, the slave initially operates in the first mode. At this time, a calibration instruction packet received at the slave input port SDI is transmitted to the output port SDO via the control unit 11. After the slave receives and forwards the calibration instruction packet, the control unit 11 controls the slave to operate in the second mode. Specifically, the control unit 11 controls the mode selection circuit 12 to short-circuit the slave input port SDI and the output port SDO to form a first path. If the slave determines that it needs to perform data calibration, it performs the data calibration and generates a calibration result. When the calibration result is a preset calibration result, the potential of the first path is set to a first level. When the calibration result is not a preset calibration result, the potential of the first path remains at a second level. If the slave does not receive the calibration instruction packet, or if the slave receives but does not forward the calibration instruction packet, the control unit 11 controls the mode selection circuit 12 to couple the slave input port SDI to the output port SDO via the control unit 11, and the slave maintains operation in the first mode. Furthermore, after the host sends a proofreading instruction data packet, within the first time, the host obtains through the above-mentioned second serial communication method whether the slave in the communication link has a feedback signal whose proofreading result is a preset proofreading result. When the first time exceeds the preset time threshold, that is, the time for the host to obtain the feedback signal from the slave is greater than the preset time threshold, the slave exits the second mode and restores the first mode, and the serial communication system exits the proofreading mode.

[0089] When the serial communication system operates in the communication mode, the control unit 11 controls the slave to always operate in the first mode. At this time, the control unit 11 controls the mode selection circuit 12 to couple the input port SDI of the slave to the output port SDO through the control unit 11 .

[0090] In this embodiment, the mode selection circuit 12 includes a selection switch S1, one end of the selection switch S1 is coupled to the output port SDO, the other end of the selection switch S1 is selectively coupled to the input port SDI or the first end of the control unit 11, and the second end of the control unit 11 is coupled to the input port SDI. Figure 5 As shown, when the slave receives a calibration instruction data packet, obtains the corresponding data, and forwards it, the control unit 11 controls the selection switch S1 to switch to node a, which is coupled to the input port SDI, so that the input port SDI and the output port SDO of the slave are short-circuited, and the slave operates in the second mode. When the slave does not receive a calibration instruction data packet or receives a calibration instruction data packet but does not forward it, the control unit 11 controls the selection switch S1 to maintain a connection with node b, which is coupled to the first end of the control unit 11, so that the input port SDI of the slave is coupled to the output port SDO through the control unit 11, and the slave operates in the first mode. The present invention is not limited to this. For example, in other embodiments, one end of the selection switch S1 is coupled to the input port SDI, the other end of the selection switch S1 is selectively coupled to the output port SDO or the first end of the control unit 11, and the second end of the control unit 11 is coupled to the output port SDO.

[0091] like Figure 5 As shown, the serial communication system further includes a pull-up circuit 2 coupled between any node between the master and the first slave and the power supply VDD. The pull-up circuit 2 is configured to pull up the initial value of the potential of the link path to a high level as a second level within a preset time threshold, with the first level configured as a low level. In this embodiment, the serial communication system includes only one pull-up circuit 2 coupled between any node between the master and the first slave and the power supply VDD, but the present invention is not limited to this. In another embodiment, the pull-up circuit 2 is built into the master. Specifically, the pull-up circuit 2 is coupled between a node coupled to the input / output multiplexing port MDI / MDO of the master and the power supply VDD. In other embodiments, the serial communication system includes multiple pull-up circuits 2 coupled between any node in the first path and the power supply VDD. In this embodiment, the pull-up circuit 2 is configured as a first resistor R1, but the present invention is not limited to this. For example, in other embodiments, the pull-up circuit 2 is configured as a power switch or a current source.

[0092] Furthermore, each slave includes a pull-down unit 13, which is coupled between any node in its own first path and the ground potential and is controlled by the control unit 11. If the proofreading result of the slave is a preset proofreading result, the control unit 11 controls the pull-down unit 13 to pull down the potential of the first path to a low level as the first level, so that the potential of the link path is pulled down to a low level. The host Master receives the low level as a first feedback signal indicating that the proofreading result of the slave in the communication link is the preset proofreading result.

[0093] In this embodiment, the first level is set to a low level, and the second level is set to a high level.

[0094] In this embodiment, the pull-down unit 13 includes a first power switch Q1 coupled between the input port SDI and ground. The pull-down unit 13 is controlled by the control unit 11. If the slave determines that its calibration result is a predetermined calibration result, the control unit 11 controls the first power switch Q1 to conduct, thereby pulling the potential of the first path down to zero (i.e., a low level). Otherwise, the first power switch Q1 is disconnected, and the potential of the first path remains high. The present invention is not limited to this. For example, in other embodiments, the first power switch Q1 is coupled between the output port SDO and ground. Furthermore, in another embodiment, the pull-down unit 13 includes a first current source coupled between any node in its first path and ground. If the slave determines that its calibration result is a predetermined calibration result, the first current source is controlled to operate, thereby pulling the potential of the first path down to zero. Otherwise, the first current source is disabled, and the potential of the first path remains high. Specifically, in this embodiment, a first power terminal of the first power switch Q1 is coupled to the input port SDI, a second power terminal of the first power switch Q1 is coupled to the ground potential, and a control terminal of the first power switch is coupled to the control unit 11. A common terminal of the first power switch Q1 and the input port SDI is coupled to node a.

[0095] In this embodiment, when the master needs to obtain the calibration results of a slave, the master's input / output multiplexing ports MDO / MDI are in output mode and the master sends a calibration instruction packet. After the master sends the calibration instruction packet, the master's input / output multiplexing ports MDO / MDI are in input mode. The first slave receives the calibration instruction packet sent by the master, obtains the first calibration sub-packet, and then forwards all data after the first calibration sub-packet in the calibration instruction packet to the second slave. The control unit 11 in the first slave controls the selector switch S1 to switch to node a, short-circuiting the input port SDI and output port SDO of the first slave to form a first path. At this time, the voltage level of the first path is high, and the voltage level of the link path from the master's input / output multiplexing ports MDO / MDI to the output terminal SDO of the first slave IC1 is high. If the control unit 11 determines that it needs to perform data calibration, it performs data calibration to generate a calibration result and determines whether its own calibration result is a preset calibration result, thereby selectively turning on or off the first power switch Q1. Specifically, if the control unit 11 of the first slave determines that the verification result is the preset verification result, the first power switch Q1 is turned on, and the voltage level of the first path is pulled down to a low level. The voltage level of the link path from the master's input / output multiplexing port MDO / MDI to the output terminal SDO of the first slave IC1 is low, and the voltage level of the master's input / output multiplexing port MDO / MDI is also low. In other words, the master receives the low voltage level as a feedback signal, indicating that a slave in the communication link has a verification result that is the preset verification result. The second slave, and so on, the nth slave, repeat the above operations in sequence. Within a preset time threshold, if the first path of a slave is pulled down to a low level, the master receives the low voltage level as a first feedback signal indicating that a slave in the communication link has a verification result that is the preset verification result. Within a preset time threshold, if the first paths in all slave devices are not pulled down to a low level, the potential of the link path formed by coupling multiple first paths in all slave devices in series remains at a high level, and the host Master receives the high level as a second feedback signal indicating that there is no slave in the communication link and the verification result is the preset verification result.

[0096] In this embodiment, the master includes an input / output multiplexing port MDO / MDI, which is configured to send calibration instruction packets and receive feedback signals from the slave. However, the present invention is not limited to this. In other embodiments, the master includes an output port and an input port, the output port being configured to send calibration instruction packets; the input port being configured to receive feedback signals. Both the input port and the output port of the master are coupled to the input port of the first slave. After the master sends the calibration instruction packet, the output port of the master is set to a high-impedance state.

[0097] In this embodiment, the output port SDO of the last slave is not coupled to the master Master, but the present invention is not limited to this. In the embodiment where the output port SDO of the last slave is coupled to the master Master, the second serial communication method can also be used for communication.

[0098] In this embodiment, the serial communication system includes a serially coupled host Master and a communication link. In another embodiment, the serial communication system includes a serially coupled host Master and N communication links, where N is greater than 1. The number of slaves in each communication link can be the same or different. Each communication link corresponds to an input / output multiplexing port of the host, that is, the N communication links correspond to the N input / output multiplexing ports of the host, and the first slave in each communication link is coupled to the corresponding input / output multiplexing port of the host. In another embodiment, the serial communication system includes a serially coupled host Master and N communication links, where N is greater than 1. The number of slaves in each communication link can be the same or different. The N communication links correspond to the same input / output multiplexing port of the host. The N communication links in the above-mentioned two serial communication systems all feed back the proofreading results to the host according to the second serial communication method in this embodiment. When there is a slave in any communication link whose proofreading result is the preset proofreading result, the host receives the first level as a first feedback signal indicating that there is a slave in the communication link whose proofreading result is the preset proofreading result; when the proofreading results of all slaves in the N communication links are not the preset proofreading results, the host receives the second level as a second feedback signal indicating that there is no slave in the communication link whose proofreading result is the preset proofreading result.

[0099] Furthermore, in this embodiment, the slave in the serial communication system has only one input port and one output port for single-line communication, but the present invention is not limited thereto. For example, in other embodiments, the slave in the serial communication system includes two input ports and two output ports, wherein one input port receives a clock signal and one output port is used to output a clock signal for I / O communication. 2 C communication.

[0100] Figure 6 This is a schematic diagram of a third embodiment of a serial communication system according to the present invention. The differences from the second embodiment are that the first level is set to a high level, the second level is set to a low level, the positions and structures of the pull-up circuit and the pull-down circuit are different, and the position of the mode selection circuit 12 is different.

[0101] Specifically, the serial communication system includes a pull-down circuit 2 configured to pull down the potential of the link path to a low level as the second level within a preset time threshold. In this embodiment, the serial communication system includes only one pull-down circuit 2, which is coupled between any node between the master Master and the first slave input port SDI and the ground potential, but the present invention is not limited to this. In another embodiment, the pull-down circuit 2 is built into the master Master. Specifically, the pull-down circuit 2 is coupled between a node coupled to the master Master's input / output multiplexing port MDO / MDI and the ground potential. In other embodiments, the serial communication system includes multiple pull-down circuits 2, that is, each slave includes a pull-down circuit 2, and the pull-down circuit 2 is coupled between any node in the first path and the ground potential. In this embodiment, the pull-down circuit 2 is configured as a first resistor R1, but the present invention is not limited to this. For example, in other embodiments, the pull-down circuit 2 is configured as a power switch or a current source.

[0102] In this embodiment, each slave includes a pull-up unit 13 coupled between any node in its first path and power supply VDD, and controlled by control unit 11. If a slave determines that it needs to perform data verification, it performs data verification to generate a verification result. If the verification result meets the predetermined verification result, control unit 11 controls pull-up unit 13 to pull the potential of the first path to a high level, thereby increasing the potential of the link path to a high level. The master receives this high level as a first feedback signal indicating that the verification result of the slave in the communication link meets the predetermined verification result. In this embodiment, pull-up unit 13 includes a first power switch Q1 coupled between any node in its first path and power supply VDD. If the verification result of the slave meets the predetermined verification result, the first power switch Q1 is controlled to conduct, thereby pulling the potential of the first path to a high level. Otherwise, the first power switch Q1 is turned off, and the potential of the first path remains at a low level. In another embodiment, the pull-up unit includes a first current source coupled between any node in its first path and a power supply VDD. If the slave determines that it needs to perform data verification, the slave performs data verification to generate a verification result. When the verification result is a preset verification result, the first current source is controlled to operate to pull the potential of the first path to a high level. Otherwise, the first current source is disabled, and the potential of the first path is maintained at a low level. If, within a preset time threshold, the first paths of all slaves are not pulled to a high level, the master receives a low level as a second feedback signal indicating that no slave in the communication link has a verification result that is the preset verification result.

[0103] The mode selection circuit 12 includes a selection switch S1. In this embodiment, one end of the selection switch S1 is coupled to the input port SDI, and the other end of the selection switch S1 is selectively coupled to the output port SDO or the first end of the control unit 11. The second end of the control unit 11 is coupled to the output port SDO, but this embodiment is not limited to this.

[0104] The rest of the description is similar to that of the second embodiment and will not be described in detail here.

[0105] It should be noted that in Example 2 and Example 3, one of the high level and the low level is used as the first level, and the other of the high level and the low level is used as the second level, but the present invention is not limited to this. In other embodiments, the first level and the second level can also be set to specific numbers, for example, 5V and 3V respectively.

[0106] The first serial communication method and the second serial communication method of the present invention are independent of each other. The first serial communication method or the second serial communication method can be implemented alone, or the first serial communication method and the second serial communication method can be implemented successively. The present invention does not limit this.

[0107] The present invention further provides a backlight system, comprising: the serial communication system of any one of the above embodiments, wherein each slave device is used to control a corresponding LED area in the backlight system.

[0108] Although the embodiments are described and explained separately above, some common technologies are involved. It is the opinion of ordinary technicians in this field that they can be replaced and integrated between the embodiments. If there is anything not clearly recorded in one of the embodiments, reference can be made to another recorded embodiment.

[0109] While embodiments of the present invention have been described above, these embodiments do not exhaustively describe all details and do not limit the invention to the specific embodiments described. Obviously, many modifications and variations are possible based on the above description. These embodiments are selected and described in detail in this specification in order to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better utilize the invention and its modifications. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A serial communication method, applied to a serial communication system, characterized in that: The serial communication system includes a host coupled in series and at least one communication link, wherein the communication link includes a plurality of slaves coupled in series in sequence, and the serial communication method includes: The host sends a calibration instruction data packet; The current slave in the communication link is in a first mode to receive a calibration instruction data packet sent by the master or a previous slave and forward it to a subsequent slave; The slave is currently controlled to be in the second mode to short-circuit its own input port and output port to form a first path; When the check instruction data packet indicates that the slave needs to check data, the slave generates a check code based on at least part of the data in its register list to check the data in the register and generate a check result; When the proofreading result is the preset proofreading result, the current slave sets the level of its first path to the first level used to represent the preset proofreading result, so that the host receives a feedback signal indicating whether the proofreading result of the slave in the communication link is the preset proofreading result.

2. The serial communication method according to claim 1, wherein: The current slave generates a check code according to at least part of the data in the register list and a preset algorithm; The check code is compared with a reference check code to generate a calibration result. When the calibration result is a preset calibration result, the current slave sets the level of its first path to a first level for representing the preset calibration result.

3. The serial communication method according to claim 2, wherein: The calibration instruction data packet includes a plurality of calibration sub-data packets arranged in sequence, and each slave device that needs calibration corresponds to a different calibration sub-data packet; The current slave receives the calibration instruction data packet sent by the host or the previous slave to obtain its own corresponding calibration sub-data packet, and sends all data after the corresponding calibration sub-data packet in the calibration instruction data packet to the next slave.

4. The serial communication method according to claim 3, wherein: The verification sub-data packet includes a reference check code, so that the current slave obtains the reference check code from the verification sub-data packet corresponding to itself.

5. The serial communication method according to claim 1, wherein: The current slave generates a check code according to the data at a preset position in the register list.

6. The serial communication method according to claim 5, wherein: The proofreading sub-data packet also includes a register address portion; The current slave determines a corresponding position in the register list according to the data of the register address portion, and generates a check code according to the data of the corresponding position in the register list.

7. The serial communication method according to claim 2, wherein: Before the host sends the calibration instruction data packet, the host generates a reference check code corresponding to each slave, and writes the reference check code corresponding to the current slave into a register corresponding to the current slave for storage.

8. The serial communication method according to claim 1, wherein: When the current slave determines that the check code is inconsistent with the reference check code, the check result is a preset check result, and the potential of the first path of the current slave is set to the first level.

9. The serial communication method according to claim 1, wherein: Within a preset time threshold, when the potential of a first path in a slave is set to a first level, the potential of a link path formed by coupling multiple first paths in series in the communication link is set to the first level, so that the host receives the first level as a first feedback signal indicating that a calibration result in a slave of the communication link is a preset calibration result.

10. The serial communication method according to claim 1, wherein: Within a preset time threshold, when the first paths in all slave machines are not set to the first level, the potential of the link path formed by coupling multiple first paths in all slave machines in series is maintained at the second level, so that the host receives the second level as a second feedback signal indicating that there is no slave machine in the communication link whose calibration result is the preset calibration result.

11. The serial communication method according to claim 1, wherein: A first slave whose own potential of the first path is set to the first level, before verifying its own data, an initial value of the potential of the link path formed by coupling multiple first paths in series in the communication link is set to the second level, and the potential of the first path in the slave is set to the second level.

12. The serial communication method according to claim 1, wherein: Each slave further includes a control unit. When the slave is in a first mode, the input port of the slave is coupled to the output port thereof through the control unit. When the slave is in a second mode, the input port and the output port of the slave are short-circuited.

13. The serial communication method according to claim 1, wherein: When the serial communication system operates in the communication mode, the slave device always operates in the first mode.

14. The serial communication method according to claim 1, wherein: When the serial communication system operates in the calibration mode, the slave first operates in the first mode to transmit the calibration instruction data packet it receives to the next slave directly or after modification, and then the slave is controlled to operate in the second mode.

15. The serial communication method according to claim 1, wherein: The serial communication system further includes a pull-up circuit configured to set an initial value of a potential of a link path formed by serially coupling a plurality of first paths in the communication link to a high level as a second level within a preset time threshold, wherein the first level is configured to be a low level.

16. The serial communication method according to claim 15, characterized in that: Each slave includes a pull-down unit coupled between any node in its own first path and the ground potential. If the slave determines that its own proofreading result is a preset proofreading result, the pull-down unit is controlled to pull down the potential of its own first path to a low level as the first level, so that the potential of the link path is pulled down from a high level to a low level.

17. The serial communication method according to claim 1, wherein: The serial communication system also includes a pull-down circuit, which is configured to set an initial value of the potential of a link path formed by serially coupling multiple first paths in the communication link to a low level as a second level within a preset time threshold, and the first level is configured to be a high level.

18. The serial communication method according to claim 17, wherein: Each slave includes a pull-up unit coupled between any node in its own first path and a power supply. If the slave determines that its own proofreading result is a preset proofreading result, the pull-up unit is controlled to pull up the potential of its own first path to a high level as a first level, so that the potential of the link path is pulled up from a low level to a high level.

19. The serial communication method according to claim 1, wherein: The slave includes a mode selection circuit and a control unit, wherein one end of the mode selection circuit is coupled to the input port of the slave, the other end of the mode selection circuit is selectively coupled to the output port of the slave and a first end of the control unit, and the second end of the control unit is coupled to the output port of the slave; The mode selection circuit is configured to be controlled by the control unit to control the slave device to operate in the first mode or the second mode.

20. The serial communication method according to claim 1, wherein: The slave includes a mode selection circuit and a control unit, one end of the mode selection circuit is coupled to the output port of the slave, the other end of the mode selection circuit is selectively coupled to the input port of the slave and a first end of the control unit, and the second end of the control unit is coupled to the input port of the slave; The mode selection circuit is configured to be controlled by the control unit to control the slave device to operate in the first mode or the second mode.

21. The serial communication method according to claim 1, wherein: The host includes an input-output multiplexing port configured to send the calibration instruction data packet and receive the feedback signal.

22. The serial communication method according to claim 1, wherein: The host comprises: an output port configured to send out the calibration instruction data packet; an input port configured to receive a feedback signal from the input port; The input port and the output port of the host are both coupled to the input port of the first slave, and after the host sends the calibration instruction data packet, the output port is set to a high impedance state.

23. The serial communication method according to claim 1, wherein: Also includes: The host sends a write instruction data packet, wherein the write instruction data packet includes a plurality of write sub-data packets arranged in sequence, and each slave device to which data needs to be written corresponds to a different write sub-data packet; The current slave in the communication link receives a write instruction data packet sent by the master or the previous slave, obtains the data before the predetermined length in the received write instruction data packet to obtain a write sub-data packet corresponding to the current slave, and sends all the data after the data before the predetermined length in the received write instruction data packet to the next slave; The predetermined length is determined by data length information represented by at least one data bit written into the corresponding sub-data packet.

24. The serial communication method according to claim 23, wherein: The write sub-data packet includes a communication data portion, and one or more identification bits are set before the communication data portion to identify the data length information of the write sub-data packet.

25. The serial communication method according to claim 24, wherein: The write sub-data packet includes a command portion, which is arranged before the communication data portion. One or more identification bits are set in the command portion to identify the data length information.

26. The serial communication method according to claim 24, wherein: The write sub-data packet includes a register address portion, which is arranged before the communication data portion. One or more identification bits are arranged in the register address portion to identify the data length information.

27. The serial communication method according to claim 24, wherein: The write sub-data packet includes a command part and a register address part, and the command part and the register address part are both set before the communication data part. One or more identification bits are set in the command part and the register address part respectively to identify the data length information.

28. The serial communication method according to claim 23, wherein: The write sub-data packet includes a communication data portion and a register address portion, wherein the register address portion is arranged before the communication data portion, and the data length information is determined according to the data of the register address portion.

29. The serial communication method according to claim 28, wherein: A mapping relationship between the data of the register address portion and the data length information of the written sub-data packet is preset in the slave device, so as to determine the data length information according to the data of the register address portion.

30. A serial communication system, characterized in that: include: A host coupled in series and at least one communication link, wherein the communication link comprises a plurality of slaves coupled in series in sequence, each slave comprising an input port and an output port, Wherein, communication is performed using the serial communication method described in any one of claims 1 to 29.

31. A backlight system, characterized in that: include: The serial communication system of claim 30, wherein each slave device is configured to control a corresponding LED zone in the backlight system.

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