I2C signal transmission method and foldable device

Abstract

The present invention discloses an I2C signal transmission method and a foldable device. In order to reduce the number of cross-screen signal lines, the I2C signal transmission method of the present invention is applied to a foldable device including a first under-screen chip, a second under-screen chip and an application processor, and a connection between the application processor and the first under-screen chip is established through an I2C_SCL signal line and an I2C_SDA signal line; a connection between the first under-screen chip and the second under-screen chip is established through a first signal line and a second signal line, and the first signal line and the second signal line are cross-screen signal lines; in a time-division multiplexing manner, the following are transmitted on the first signal line and the second signal line: an I2C signal sent by the application processor through the I2C_SCL signal line and the I2C_SDA signal line, and a first type of signal sent by the application processor through other signal lines other than the I2C_SCL signal line and the I2C_SDA signal line. The present invention can reduce the number of cross-screen signal lines and reduce costs. The present invention is suitable for the field of signal bridging and conversion.

Description

Technical Field

[0001] The invention relates to the field of signal bridging and conversion, and in particular to an I2C signal transmission method and a foldable device. Background Art

[0002] The most common foldable device is a foldable dual-screen mobile phone, which is an important branch in the current smartphone field. There is a chip under each screen. The first chip under the same screen as the application processor is under the first screen, and the second chip under the other screen is under the second screen.

[0003] Figure 1 The physical position relationship and logical connection relationship between the application processor and the first and second under-screen chips in a dual-screen mobile phone are shown. When the application processor configures the two under-screen chips, it configures the first under-screen chip through the (Inter-Integrated Circuit, I2C) interface, and routes the I2C signal to the second under-screen chip through the first under-screen chip and configures the second under-screen chip. In addition, the first screen and the second screen are connected by a hinge, and the application processor, the first under-screen chip and the second under-screen chip are electrically connected in sequence and can exchange data.

[0004] For small devices such as mobile phones, internal size, area and other resources are extremely limited. The more chip pins and / or cross-screen signal lines there are, the higher the packaging cost, circuit board routing and other costs will be.

[0005] The existing technology communicates with the second under-screen chip by adding two I2C input / output (I / O) pins, which consumes a certain amount of chip pin resources. One of the main goals of the current I / O pin aggregation solution is to reduce the number of cross-screen signal lines.

[0006] In addition, even if there are some differences between the first under-screen chip and the second under-screen chip, and they constitute two different chips, it will cost a very high R&D and manufacturing cost to design, test, and manufacture the two different chips. Therefore, if the I / O pin aggregation solution can further enable the two under-screen chips to have the same circuit design, the overall cost of the under-screen chips can be further reduced.

[0007] How to reduce the number of chip pins and / or cross-screen signal lines is a technical problem that needs to be solved urgently in this field. Summary of the invention

[0008] In order to alleviate or partially alleviate the above technical problems, the solution of the present invention is as follows:

[0009] An I2C signal transmission method is applied to a foldable device including a first chip under the screen, a second chip under the screen and an application processor, wherein a connection is established between the application processor and the first chip under the screen through an I2C_SCL signal line and an I2C_SDA signal line; a connection is established between the first chip under the screen and the second chip under the screen through a first signal line and a second signal line, and the first signal line and the second signal line are cross-screen signal lines; and the following are transmitted on the first signal line and the second signal line in a time division multiplexing manner: an I2C signal sent by the application processor through the I2C_SCL signal line and the I2C_SDA signal line, and a first type of signal sent by the application processor through signal lines other than the I2C_SCL signal line and the I2C_SDA signal line.

[0010] Furthermore, in the first under-screen chip, the I2C_SCL signal line and the I2C_SDA signal line are connected, and the first signal line and the second signal line are connected; through a plurality of multiplexers, the connection between the first signal line and the I2C_SCL signal line is enabled, and the connection between the second signal line and the I2C_SDA signal line is enabled to realize the transmission of the I2C signal; through a plurality of multiplexers, the first type of signal is enabled and connected to the first signal line and the second signal line.

[0011] Furthermore, the first under-screen chip also includes: a first detection module, a second detection module and a first I2C to APB module; if the first detection module detects that the I2C signal includes a start flag, and the address in the I2C signal belongs to a first address set, the first I2C to APB module converts the I2C signal into a first APB command to access the on-chip register of the first under-screen chip; the second detection module detects the stop flag in the I2C signal; wherein the first address set belongs to the address set of the first under-screen chip.

[0012] Furthermore, in the second chip under the screen, the first signal line and the second signal line are connected; the second chip under the screen also includes: a third detection module, a fourth detection module and a second I2C to APB module; if the third detection module detects that the signal input by the first signal line and the second signal line includes a start mark, and the acquired address belongs to the second address set, the first I2C to APB module converts the signal input by the first signal line and the second signal line into a second APB command to access the on-chip register of the second chip under the screen; the fourth detection module detects the stop mark in the signal input by the first signal line and the second signal line; wherein, the second address set belongs to the address set of the second chip under the screen.

[0013] Further, if the first detection module detects that the I2C signal includes a start flag, the second detection module is enabled.

[0014] Further, if the third detection module detects that the signals inputted from the first signal line and the second signal line include a start mark, the fourth detection module is enabled.

[0015] Furthermore, when the second chip under the screen completes configuration, the shielded I2C signal is routed to the second chip under the screen.

[0016] Furthermore, the circuits of the first under-screen chip and the second under-screen chip are the same.

[0017] Furthermore, the first under-screen chip also includes a first multiplexer and a second multiplexer;

[0018] In the default setting, the first multiplexer selects the return signal output from the first under-screen chip as the first multiplexer output signal, and the second multiplexer selects the return signal output from the first under-screen chip as the second multiplexer output signal; if it is detected that the address in the I2C signal belongs to the second address set, the first multiplexer selects the return signal output from the first signal line as the first multiplexer output signal, and the second multiplexer selects the return signal output from the second signal line as the second multiplexer output signal.

[0019] A foldable device comprises a first under-screen chip, a second under-screen chip and an application processor, wherein the foldable device applies any one of the aforementioned I2C signal transmission methods.

[0020] The technical solution of the present invention has one or more of the following beneficial technical effects:

[0021] (1) By reusing I / O pins, the number of cross-screen signal lines is reduced, the packaging cost is reduced, and the number and complexity of circuit board routing are reduced, thereby reducing the circuit board cost.

[0022] (2) Two identical under-screen chips can be used to implement the routing or transmission of I2C commands, reducing various chip costs.

[0023] In addition, other beneficial effects of the present invention will be mentioned in the specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 This is a schematic diagram of the chip relationship in a dual-screen mobile phone;

[0025] Figure 2 It is a schematic diagram of the overall solution for cross-screen chip communication;

[0026] Figure 3 This is a schematic diagram of the address filtering scheme of the first under-screen chip;

[0027] Figure 4 This is a schematic diagram of the address filtering scheme of the second under-screen chip;

[0028] Figure 5 This is a schematic diagram of the data return solution. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] In order to clearly describe the technical solutions of the embodiments of the present invention, in the embodiments of the present invention, words such as "first" and "second" are used to distinguish the same or similar items with substantially the same functions and effects. Those skilled in the art can understand that words such as "first" and "second" do not limit the quantity and execution order.

[0031] Figure 2 This is a schematic diagram of the overall cross-screen chip communication solution. In a dual-screen mobile phone, it includes an application processor, a first under-screen chip, and a second under-screen chip. The first under-screen chip and the application processor are located under the first screen, and the second under-screen chip is located under the second screen.

[0032] The application processor configures the first under-screen chip through the I2C interface. The I2C interface connects two signal lines to the first under-screen chip, namely an I2C_SCL signal line and an I2C_SDA signal line, for transmitting I2C signals.

[0033] The I2C_SCL signal line is a serial clock line (SCL) responsible for generating a synchronous pulse clock, and the I2C_SDA signal line is a serial data line (SDA) responsible for transmitting serial data. The I2C_SCL signal line and the I2C_SDA signal line are traditional signal lines connecting the application processor and the first under-screen chip, because both the application processor and the first under-screen chip are located under the first screen.

[0034] The I2C signal includes an I2C_SDA signal and an I2C_SCL signal. The I2C_SDA signal line is used to transmit the I2C_SDA signal, and the I2C_SCL signal line is used to transmit the I2C_SCL signal.

[0035] Figure 2Two SPI interfaces are given as examples: SPI1 interface and SPI2 interface. SPI signals are sent and received between the application processor and the first under-screen chip by means of other interfaces other than the aforementioned I2C interface or other signal lines other than the I2C_SCL signal line and the I2C_SDA signal line, such as the SPI1 interface and the SPI2 interface and the signal line connected to the first under-screen chip.

[0036] In addition to the SPI1 interface and the SPI2 interface, several other types of interfaces may be included between the application processor and the first under-screen chip, which may be set according to actual application needs. These other types of interfaces may be used as other interfaces besides the I2C interface to be used as multiplexed signal lines for transmitting the aforementioned I2C signals. The present invention is not limited to this and is not limited thereto.

[0037] The first under-screen chip includes two edge detection modules, which are respectively used to detect the SPI signals output by the SPI2 interface and the SPI1 interface, and respectively output the tx_data0 signal and the tx_data1 signal to the two edge receiving modules in the second under-screen chip. The two edge receiving modules respectively send the SPI signals to sensor 1 and sensor 2 through the two ports of the second under-screen chip.

[0038] The first under-screen chip includes two edge detection modules, both detecting the rx_data0 signal output from the frame data generation module in the second under-screen chip. The frame data generation module receives the SPI signals respectively sent by sensor 1 and sensor 2 from the aforementioned two ports of the second under-screen chip.

[0039] Optionally, the first chip under the screen may also send a tx_clk clock signal to the second chip under the screen.

[0040] In the present invention, the tx_data0 signal, the tx_data1 signal, the rx_data0 signal and the tx_clk clock signal are all transmitted via the cross-screen signal line.

[0041] In the present invention, the tx_data0 signal and the tx_data1 signal are signals sent by the application processor to the second chip under the screen, and are first type signals sent based on the exemplary SPI1 interface and SPI2 interface.

[0042] In the present invention, in order to reduce or not increase the cross-screen signal lines between the first screen and the second screen, when configuring the second screen, the first signal line for transmitting tx_data0 data is multiplexed as a signal line for transmitting the I2C_SCL signal, and the second signal line for transmitting tx_data1 data is multiplexed as a signal line for transmitting the I2C_SDA signal, so as to realize the configuration of the second screen.

[0043] Furthermore, the configuration of the second screen refers to the configuration of various registers of the chip under the second screen.

[0044] Furthermore, the multiplexing is time division multiplexing.

[0045] Preferably, the first under-screen chip and the second under-screen chip in the present invention may be exactly the same chip.

[0046] Figure 3 The schematic diagram of the address filtering scheme of the first chip under the screen is shown. The first chip under the screen includes a first detection module, a second detection module, and a first I2C to Advanced Peripheral Bus (APB) module. In the first chip under the screen, the I2C_SCL signal line and the I2C_SDA signal line are connected, and the first signal line and the second signal line are connected. Here, the technical terms "connect" and "connect" in this field refer to whether the signal is input into the first chip under the screen or the signal is output from the first chip under the screen.

[0047] The first chip under the screen receives an I2C signal from the application processor according to the I2C_SCL signal line and the I2C_SDA signal line. The I2C signal generally includes a start flag, an address, intermediate data, and a stop flag.

[0048] The first under-screen chip stores a first address set and a second address set, wherein the first address set belongs to the address set of the first under-screen chip, and the second address set belongs to the address set of the second under-screen chip.

[0049] The I2C_SCL signal line and the I2C_SDA signal line are connected to the first detection module. The first detection module detects the start mark according to the received I2C signal, and if the start mark is detected, determines whether the address in the I2C signal belongs to the first address set or the second address set by address comparison.

[0050] If the comparison result indicates that it belongs to the first address set, the I2C signal is converted into a first APB command through the first I2C to APB module, such as for accessing the on-chip register of the first under-screen chip, and the second detection module is enabled.

[0051] Furthermore, the I2C_SCL signal line and the I2C_SDA signal line can be directly connected to the first I2C to APB module and at least used to transmit intermediate data in the I2C signal.

[0052] If the comparison result indicates that it belongs to the second address set, shutting down the second detection module can save power consumption, and does not instruct the first I2C to APB module to convert the I2C signal into the first APB command. In other words, the I2C signal will not be converted into the first APB command.

[0053] The I2C_SCL signal line and the I2C_SDA signal line are also connected to the second detection module. The second detection module is used to detect the stop sign in the I2C signal and send the detected result to the first I2C to APB module.

[0054] For example, when the first I2C to APB module receives information indicating that a stop sign is detected, it stops converting the I2C signal into the first APB command.

[0055] Through a plurality of multiplexers, the connection between the first signal line and the I2C_SCL signal line is gated, and the connection between the second signal line and the I2C_SDA signal line is gated to realize the transmission of the I2C signal. In addition, through a plurality of multiplexers, the first type of signal is gated to the first signal line and the second signal line. By making the above gates in different time periods, the time division multiplexing of the first signal line and the second signal line can be realized.

[0056] Furthermore, by default, the I2C signals transmitted by the I2C_SCL signal line and the I2C_SDA signal line are transmitted to the second under-screen chip via the first signal line and the second signal line respectively. A specific implementation of the gating may be to gating a plurality of multiplexers by configuring a register. For example, gating by configuring a register Figure 2 The input signal can be switched by a specific combination of multiplexers in the multiplexer. The input "1" of the multiplexer is a constant high level.

[0057] The first signal line is also used to transmit the tx_data0 signal, and the second signal line is also used to transmit the tx_data1 signal. Through time division multiplexing, the first signal line and the second signal line can transmit different types of signals. Because of this, it is possible to avoid adding two cross-screen signal lines between the first under-screen chip and the second under-screen chip to transmit I2C signals. Figure 2 In the figure, tx_data0 / I2C_SCL is used to express that the first signal line can transmit two signals, and tx_data1 / I2C_SDA is used to express that the second signal line can transmit two signals.

[0058] Furthermore, the I2C signal can be shielded from being transmitted or routed to the second chip under the screen by configuring the register. Typically, the shielding step occurs after the second chip under the screen is configured.

[0059] Figure 4 A schematic diagram of the address filtering solution of the second under-screen chip is shown. In the second under-screen chip, the first signal line and the second signal line are connected to the third detection module.

[0060] The third detection module detects whether the signals input by the first signal line and the second signal line contain a start mark. If there is a start mark, then the address following the start mark is obtained to determine whether it belongs to the second address set. If the address in the I2C signal belongs to the second address set, it is considered that the first signal line and the second signal line transmit an I2C signal. Then the second I2C to APB module converts the I2C signal into a second APB command to access the on-chip register of the second under-screen chip.

[0061] When the revelation sign is detected, the fourth detection module will also be enabled. Otherwise, the fourth detection module will be turned off. The purpose of enabling the fourth detection module is to detect whether a stop sign appears through the fourth detection module.

[0062] The first signal line and the second signal line are connected to the second I2C to APB module and are used at least to transmit intermediate data in the I2C signal.

[0063] The first signal line and the second signal line are connected to the fourth detection module to detect the stop sign in the I2C signal, and send the detected result to the second I2C to APB module.

[0064] For example, when the second I2C to APB module receives information indicating that a stop sign is detected, it stops converting the I2C signal into the second APB command.

[0065] First, the start flag and address are compared according to the received I2C signal. If they belong to the second address set, the third detection module is enabled, and the I2C command is converted into an APB command through the I2C to APB module to access the on-chip registers of the second under-screen chip; if it does not belong to the second address set, the third detection module is turned off to reduce power consumption.

[0066] In addition, although Figure 3 and Figure 4 There are certain differences in the information processing logic of the display, but in fact the first under-screen chip and the second under-screen chip can adopt the same circuit design, and only some functional modules need to be turned off in actual use.

[0067] Figure 5 A schematic diagram of a data return scheme is shown. The first multiplexer and the second multiplexer are applied to the first under-screen chip.

[0068] On the one hand, for the return data of the clock signal, the first multiplexer selects the I2C_SCL_o return signal output from the first under-screen chip as the first multiplexer output signal by default.

[0069] When the address comparison detection result indicates that the address in the I2C signal belongs to the second address set, the first multiplexer selects the I2C_SCL_o return signal output from the first signal line as the first multiplexer output signal. When the fourth detection module detects information indicating that a stop sign is detected, the first multiplexer continues to select the default I2C_SCL_o return signal output from the first under-screen chip as the first multiplexer output signal.

[0070] On the other hand, for the return data of the serial data, the second multiplexer selects the I2C_SDA_o return signal output from the first under-screen chip as the second multiplexer output signal by default. When the address comparison detection result indicates that the address in the I2C signal belongs to the second address set, the second multiplexer selects the I2C_SDA_o return signal output from the second signal line as the second multiplexer output signal. When the fourth detection module detects information indicating that a stop sign has been detected, the second multiplexer continues to select the default I2C_SDA_o return signal output from the first under-screen chip as the second multiplexer output signal.

[0071] Further, if the address comparison detection result indicates that the address in the I2C signal belongs to the first address set, or belongs neither to the first address set nor to the second address set, the second multiplexer continues to select the default I2C_SDA_o return signal output from the first under-screen chip as the second multiplexer output signal.

[0072] In addition, since the positions and logical relationships of the first under-screen chip, the second under-screen chip and the application processor are different, if the two under-screen chips are designed as two different chips, this will increase the various costs of chip design, manufacturing, testing, etc. The present invention can implement the routing or transmission of I2C commands by two completely identical under-screen chips, thereby reducing various chip costs.

[0073] In order to better illustrate the present invention, numerous specific details are provided in the above specific embodiments. It should be understood by those skilled in the art that the present invention can also be implemented without certain specific details. In some examples, methods, means, components and circuits well known to those skilled in the art are not described in detail in order to highlight the subject matter of the present invention.

[0074] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

Claims

1. An I2C signal transmission method, applied to a foldable device including a first under-screen chip, a second under-screen chip and an application processor, characterized in that: Establish a connection between the application processor and the first under-screen chip through the I2C_SCL signal line and the I2C_SDA signal line; A connection is established between the first under-screen chip and the second under-screen chip through the first signal line and the second signal line, and the first signal line and the second signal line are cross-screen signal lines; Transmitting, on the first signal line and the second signal line, by time division multiplexing: an I2C signal sent by the application processor through the I2C_SCL signal line and the I2C_SDA signal line, and a first type of signal sent by the application processor through signal lines other than the I2C_SCL signal line and the I2C_SDA signal line; and, In the first under-screen chip, the I2C_SCL signal line and the I2C_SDA signal line are connected, and the first signal line and the second signal line are connected; By using a plurality of multiplexers, the connection between the first signal line and the I2C_SCL signal line is selected, and the connection between the second signal line and the I2C_SDA signal line is selected, so as to realize the transmission of the I2C signal; The first type of signal is selected and connected to the first signal line and the second signal line through a plurality of multiplexers.

2. The I2C signal transmission method according to claim 1, characterized in that: The first under-screen chip also includes: a first detection module, a second detection module and a first I2C to APB module; If the first detection module detects that the I2C signal includes a start flag, and the address in the I2C signal belongs to the first address set, the first I2C to APB module converts the I2C signal into a first APB command to access the on-chip register of the first under-screen chip; The second detection module detects the stop sign in the I2C signal; wherein, The first address set belongs to the address set of the first under-screen chip.

3. The I2C signal transmission method according to claim 2, characterized in that: In the second under-screen chip, the first signal line and the second signal line are connected; The second under-screen chip also includes: a third detection module, a fourth detection module and a second I2C to APB module; If the third detection module detects that the signals input by the first signal line and the second signal line include a start flag, and the acquired address belongs to the second address set, the first I2C to APB module converts the signals input by the first signal line and the second signal line into a second APB command to access the on-chip register of the second under-screen chip; The fourth detection module detects the stop sign in the signal input from the first signal line and the second signal line; wherein, The second address set belongs to the address set of the second under-screen chip.

4. The I2C signal transmission method according to claim 3, characterized in that: If the first detection module detects that the I2C signal includes a start mark, the second detection module is enabled.

5. The I2C signal transmission method according to claim 4, characterized in that: If the third detection module detects that the signals inputted from the first signal line and the second signal line include a start mark, the fourth detection module is enabled.

6. The I2C signal transmission method according to claim 5, characterized in that: When the second chip under the screen is configured, the shielded I2C signal is routed to the second chip under the screen.

7. The I2C signal transmission method according to claim 6, characterized in that: The circuits of the first under-screen chip and the second under-screen chip are the same.

8. The I2C signal transmission method according to claim 7, characterized in that: The first under-screen chip also includes a first multiplexer and a second multiplexer; In a default setting, the first multiplexer selects a return signal output from the first under-screen chip as the first multiplexer output signal, and the second multiplexer selects a return signal output from the first under-screen chip as the second multiplexer output signal; If it is detected that the address in the I2C signal belongs to the second address set, the first multiplexer selects the return signal output from the first signal line as the first multiplexer output signal, and the second multiplexer selects the return signal output from the second signal line as the second multiplexer output signal.

9. A foldable device, comprising a first under-screen chip, a second under-screen chip and an application processor, characterized in that: The foldable device applies the I2C signal transmission method described in any one of claims 1-8.

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