Screen refreshing method for handheld device and handheld device

Abstract

The present invention provides a screen refresh method for a handheld device and the handheld device, the method comprising obtaining the current screen display mode and first image data corresponding to the screen display mode; obtaining the characteristics of the image data to be refreshed corresponding to the screen display mode, obtaining the image data to be refreshed from the first image data, and setting a header in front of each row or column of the image data to be refreshed to generate second image data; a DMA controller sends the second image data to an LCD drive module through a transmission bus, so that the screen is partially refreshed. The method realizes partial row or column refresh and black and white color data compression, further reduces the amount of data transmitted by the bus, thereby improving the refresh speed of the display screen and reducing power consumption, so as to be suitable for the application of handheld devices in industrial sites.

Description

Technical Field

[0001] The present invention relates to an image display technology in the technical field of instrument calibration, and in particular to a screen refresh method for a handheld device and the handheld device. Background Art

[0002] In the instrumentation industry, high-precision instruments usually need to be calibrated regularly with calibration devices, especially on-site portable calibration devices, such as handheld calibrators and recorders for process detection quantities such as pressure, temperature, and humidity. They are generally required to be small and easy to carry, and their internal hardware resources (such as power supply) are limited accordingly. In some occasions, the inspection time is long and the display needs to be in display state for a long time, and uninterrupted detection and display are performed. Such applications usually use liquid crystal displays (LCDs). When LCD displays, they usually use a fixed refresh rate and full-screen refresh mode to update the image display. For portable handheld devices, full-screen refresh consumes more power and processing resources, which is not conducive to reducing power consumption.

[0003] For handheld devices used for industrial detection or verification, the CPU sends image display data to the LCD display screen for display through the SPI bus or other similar low-speed working buses. In this process, the image data transmission will take a long time, such as 100ms, while the industrial data in the image display is often generated very quickly. For example, the pressure acquisition module collects pressure in a cycle of 10ms. When the LCD display screen is refreshed, the previous frame of the image has not been transmitted yet, and the next frame of the image has been generated. The next few frames of image data will be lost or the task will be waiting. There are two common solutions to this problem in the existing technology:

[0004] First, choosing a high-speed bus speeds up the transmission of image data, but the CPU is always in a high-load operation state, and the high-speed bus consumes a lot of power, resulting in industrial detection equipment or calibration devices, especially handheld devices for on-site use, having a large overall power consumption, which does not meet industrial operation requirements.

[0005] Second, a low-speed bus is still used to reduce the signal acquisition frequency. For example, the acquisition period of the pressure signal is set to 100ms to make it equivalent to the bus transmission period. The resulting problem is that the real-time performance of signal acquisition and display is greatly reduced. Summary of the invention

[0006] The object of the present invention is to provide a screen refreshing method for a handheld device.

[0007] The present invention adopts the following technical solutions:

[0008] A screen refresh method for a handheld device, the handheld device comprises a processor integrated on an MCU mainboard, a storage, a DMA controller and a MEMORY LCD screen connected to the MCU mainboard signal, the MEMORY LCD screen is provided with an LCD driver module, and the LCD driver module is connected to the MCU mainboard via a transmission bus interface, the method comprises the following steps:

[0009] A first image data acquisition step, in which the processor acquires the current screen display mode of the screen of the handheld device and the first image data corresponding to the screen display mode, and stores them in a first cache unit of the memory;

[0010] In a second image data acquisition step, the processor acquires features of the image data to be refreshed corresponding to the screen display mode, acquires the image data to be refreshed from the first cache unit, and sets a header in front of each row or column of the image data to be refreshed, generates second image data, and stores the second image data in a third cache unit of the memory; wherein the features of the image data to be refreshed at least include location information of the image data to be refreshed, and the header includes at least a row number or a column number of the image data to be refreshed;

[0011] In the screen refresh step, the DMA controller sends the second image data stored in the third cache unit to the LCD drive module of the screen of the handheld device through the transmission bus, so that the screen is refreshed.

[0012] In the above screen refresh method for a handheld device, the second image acquisition step comprises:

[0013] A first refresh position data acquisition step, in which the processor acquires display position data of the image data to be refreshed as first refresh position data, and stores the data in the second cache unit of the memory;

[0014] In the second image data generation step, the processor obtains the row number or column number of the currently refreshed image data from the second cache unit, and obtains the image data corresponding to the row number or column number from the first cache unit, and adds the row number in front of each row of image data, or adds the column number in front of each column of image data, generates the second image data, and stores it in the third cache unit.

[0015] In the above screen refresh method for a handheld device, the first refresh position data acquisition step further includes the following steps:

[0016] The processor determines whether the data content and state of the image data to be refreshed acquired last time are consistent with the content and state of the image data to be refreshed acquired currently. If they are consistent, the corresponding first refresh position data is set to zero.

[0017] In the above screen refresh method for a handheld device, the characteristics of the image data to be refreshed also include color information of the image data to be refreshed, and the second image data acquisition step includes the following steps:

[0018] The first refresh position data and first color position data acquisition step, the processor acquires the position data of the image data to be refreshed as the first refresh position data, and stores it in the second cache unit of the memory; acquires the position data displayed in black and white in the first image data as the first color position data, and stores it in the fourth cache unit of the memory;

[0019] In the second image data compression generation step, the processor obtains the row number or column number of the image data to be refreshed from the second cache unit, obtains the row number or column number displayed in black and white in the first image data from the fourth cache unit, and obtains the image data to be refreshed corresponding to the row number or column number of the first refresh position data from the first cache unit, performs image data compression processing on the row or column corresponding to the first color position data in the image data to be refreshed, and combines the black and white color identifier with the row number or column number into a header, which is placed in front of the image data in the row or column, generates second image data, and stores it in the third cache unit.

[0020] In the above screen refresh method for a handheld device, the image data compression process refers to compressing the image data pixel storage bits from multiple bits to 1 bit.

[0021] In the above-mentioned screen refresh method for handheld devices, the screen display modes include three types, namely, a display mode with a higher refresh frequency in a partial area corresponds to the first working mode of the handheld device, a display mode with a lower overall refresh frequency corresponds to the second working mode of the handheld device, and a display mode with a higher overall refresh frequency corresponds to the third working mode of the handheld device.

[0022] In the above-mentioned screen refresh method for handheld devices, the refresh mode of the MEMORY LCD screen of the handheld device is periodic refresh, real-time refresh or a combination of periodic refresh and real-time refresh, wherein the triggering condition of real-time refresh includes the processor receiving a screen operation instruction or receiving an instruction from a host computer or other device through a communication interface.

[0023] In the above screen refresh method for handheld devices, the scheme of combining periodic refresh with real-time refresh is:

[0024] After executing a real-time refresh, the processor uses the time of the real-time refresh as the starting time of a new refresh cycle and retimes the refresh cycle.

[0025] The present invention also provides a handheld device, which includes an MCU mainboard and a MEMORY LCD screen. The MEMORY LCD screen is provided with an LCD driving module, and the LCD driving module is connected to the MCU mainboard through a transmission bus interface. The MCU mainboard includes:

[0026] A first image data acquisition unit, used to acquire a current screen display mode of the screen of the handheld device and first image data corresponding to the screen display mode, and store the first image data in a first cache unit;

[0027] a second image data acquisition unit, configured to acquire the image data to be refreshed from the first cache unit according to the characteristics of the image data to be refreshed corresponding to the screen display mode, and to set a header in front of each row or column of the image data to be refreshed, to generate second image data, and to store the second image data in a third cache unit; wherein the characteristics of the image data to be refreshed at least include the position information of the image data to be refreshed as the first refresh position data, and the header at least includes the row number or column number of the image data to be refreshed;

[0028] The image refresh unit is used to send the second image data stored in the third cache unit to the LCD drive module of the screen of the handheld device through a transmission bus to refresh the screen.

[0029] In the above handheld device, the second image data acquisition unit is further used to cache the position data displayed in black and white in the first image data as the first color position data;

[0030] The second image data acquisition unit is used to obtain the row number or column number of the image data to be refreshed from the second cache unit, obtain the first color position data from the fourth cache unit, and obtain the image data to be refreshed corresponding to the first refresh position data from the first cache unit, perform image data compression processing on the row or column corresponding to the first color position data in the image data to be refreshed, and combine the black and white color identification with the row number or column number into a header, which is placed in front of the image data in the row or column, to generate second image data, and store it in the third cache unit.

[0031] The present invention has the following characteristics due to the above design:

[0032] The present invention utilizes the characteristics of a MEMORY LCD screen having a pixel storage function and a row or column refresh, adopts a screen horizontal partition or a vertical partition method, performs a partial refresh of the MEMORY LCD screen according to a preset refresh frequency of each area, and adopts a DMA method to transmit image data, thereby improving the screen refresh speed and reducing power consumption; further, utilizing the characteristic of a MEMORY LCD screen having a mixed color display function, sets the pixel color of each area according to a preset refresh rate of each area, compresses black and white image data, and realizes CPU data processing and data transmission in parallel by setting a cache, further improving the data transmission rate, reducing resource consumption, and thus reducing power consumption, so as to be suitable for the application of handheld devices in industrial sites. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 It is a structural schematic diagram of Embodiment 1 of the device of the present invention;

[0034] Figure 2 It is a structural schematic diagram of Embodiment 2 of the device of the present invention;

[0035] Figure 3 The figure is a flow chart of the image refreshing method of the present invention.

[0036] Main markings:

[0037] 100-MCU mainboard; 200-MEMORY LCD screen, 201-LCD driver module;

[0038] 1- Processor;

[0039] 2-memory, 21-first cache unit, 22-second cache unit, 23-third cache unit, 24-fourth cache unit;

[0040] 3-DMA controller;

[0041] 4-bus interface;

[0042] 5- Communication interface. DETAILED DESCRIPTION

[0043] For handheld devices used in industrial sites, such as pressure detection or calibration devices, due to limited resources and power capacity, conventional LCD screens frequently refresh at a fixed frequency and refresh the screen as a whole, consuming a large amount of resources and electricity, and cannot meet the needs of industrial site use; on the other hand, in the field of industrial handheld devices, the CPU sends image display data to the LCD display for display. For the SPI bus or other similar low-speed working buses, this transmission will take a long time, and the generation of industrial data in the image display is often very fast, which will cause image data frame loss or task waiting. In the existing solutions, a high-speed transmission bus is used, and the overall power consumption is large, which does not meet the field application requirements of handheld devices. For solutions that reduce the frequency of data acquisition, the real-time performance of signal acquisition and display is greatly reduced.

[0044] In order to solve the above problems, alleviate the situation of tight resources and small power capacity of handheld devices, and meet the real-time requirements of signal acquisition and display, the present invention provides a screen refresh method for a handheld device and the handheld device. The screen used in the handheld device is a low-power MEMORY LCD screen (also known as a memory liquid crystal screen) with a memory display function. The MEMORY LCD screen also has the characteristics of pixel storage function, line update function, etc., and is particularly suitable for application scenarios of the handheld device.

[0045] The handheld device or apparatus based on the MEMORY LCD screen refresh technology of the present invention can be a handheld calibrator or recorder for pressure, temperature, humidity, process (instrument), etc. Figure 1 and Figure 2 The typical configuration of the handheld device is shown (only the part related to the implementation of the present invention is shown). The handheld device includes an MCU mainboard 100 and a MEMORY LCD screen 200, wherein the MEMORY LCD screen 200 is provided with an LCD driver module 201 (which has the function of storing image data). The MCU mainboard 100 is connected to the LCD driver module 201 via a transmission bus interface 4 to realize display control of the MEMORY LCD screen 200.

[0046] The MCU mainboard 100 is provided with a processor (CPU) 1, a memory 2 and a DMA controller 3, wherein: the memory 2 is the main storage unit of the MCU mainboard, including, for example, CPU registers (integrated in the CPU chip), ROM, RAM (memory), CPUCache (may be integrated in the CPU chip or as a CPU peripheral), etc., for storing data to be written into the LCD driver module 201 and image refresh data; the DMA controller 3 can be an independent peripheral integrated on the CPU chip, and can also be integrated inside the CPU chip in an embedded system; the memory 2, the processor 1, the DMA controller 3, and the bus interface 4 are all mounted on the system bus, and communicate and interact with the outside world through the system bus via the communication interface 5.

[0047] Furthermore, the ROM of the memory 2 pre-stores image template data corresponding to the screen size of the MEMORY LCD screen. The image template data is generally the image data displayed on the screen and the position information of each image element (such as the row number or column number where the image element is located) pre-set by the user, including the display position data (for example, the row number or column number of the screen where the icon is located) and image data (for example, image shape, size, structure, etc.) corresponding to each icon that may need to be displayed on the screen, and the display position data and image data corresponding to each detection quantity (for example, physical quantities such as pressure, temperature, and humidity). Among them, each detection quantity can be obtained from the built-in detection module of the device (for example, pressure acquisition module, temperature sensor module, humidity detection module, etc.), or can be obtained from an external metering device (for example, pressure transmitter, thermal resistor / thermocouple, hygrometer, etc.) through a communication interface, and the change information in the image data (for example, the detection quantity value information that causes the image data display area value display to change, the color change of the image data, the shape change information or other display change information) can be obtained from the MEMORY LCD screen 200 (for example, the image data change caused by the interface operation), or the value of the detection quantity in the image data pre-stored in the ROM of the memory 2. The RAM of the memory 2 opens up multiple logical cache units, including at least a first cache unit 21, a second cache unit 22 and a third cache unit 23, and may further include a fourth cache unit 24. Different cache units are used to store image data of different contents during screen refresh to facilitate parallel processing of image data.

[0048] As mentioned above, the MCU mainboard 100 and the MEMORY LCD screen 200 are connected through the transmission bus interface 4 and the LCD driver module 201. Usually, the LCD driver module 201 is connected to the bus interface 4 of the MCU mainboard through three signal lines, which are the data signal line MOSI, the clock signal line SPCK and the chip select signal line CS. The MCU mainboard 100 controls the display refresh of the MEMORY LCD screen 200 through the system bus and the three signal lines. For example:

[0049] For the bus interface 4 of the SPI protocol, the processor 1 obtains the SPI clock signal SPCK, data signal MOSI and chip select signal CS, combines the above three signals according to the timing required by the MEMORY LCD screen 200, generates the control signal and data signal required by the LCD, and extracts the corresponding image template data from the ROM of the memory 2 to the memory RAM, generates the image data to be refreshed in combination with the detection quantity data (such as physical quantity value, time stamp) obtained in the detection, and stores it in the corresponding cache unit of the memory (RAM) according to the SPI protocol. When the image of the MEMORY LCD screen 200 needs to be refreshed, the processor 1 initializes the DMA controller 3 and sends an operation command to the bus interface 4 through the system bus, and the bus interface 4 makes a request to the DMA controller 3; the DMA controller 3 makes a bus request to the processor 1, and the bus control right can be released when the CPU completes the current bus cycle, and the DMA controller 3 notifies the bus interface 4 to start DMA data transmission, and transmits the processed refresh image data from the memory through the SPI bus interface 4 to the LCD driver module 201, and finally the LCD driver module 201 refreshes the screen image according to the stored image data. Here, by controlling the DMA controller 3, data can be directly transferred between the memory 2 and the external device (i.e., the MEMORY LCD screen 200), and the processor (CPU) 1 does not need to be involved in the transfer process. Meanwhile, during the image data DMA transmission process, the CPU can simultaneously execute processing operations to achieve parallel work with data transmission, thereby improving the efficiency of the CPU.

[0050] The format of the data to be refreshed transmitted by the present invention is as follows:

[0051] The data format sent by the MCU mainboard 100 to the MEMORY LCD screen 200 is LineX+image data, or ColumnY+image data, where LineX is the row number information and ColumnY is the column number information; after receiving the refresh data, the LCD driver module 201 can control the display screen to refresh only the corresponding row or column area by identifying the LineX or ColumnY information, and control other rows or columns not to refresh but to display according to the original display content. Through this partial refresh, the amount of data transmitted by the bus between the MCU mainboard 100 and the MEMORY LCD screen 200 can be reduced, thereby increasing the refresh speed.

[0052] Furthermore, during the refresh process, the area rows or columns where the image data with unupdated content is located are not refreshed.

[0053] The MEMORY LCD screen refresh mode is periodic refresh, real-time refresh or a combination of periodic refresh and real-time refresh, wherein the triggering conditions of real-time refresh include screen operation or receiving instructions from a host computer or other devices through a communication interface.

[0054] Based on the above-mentioned format of the image data to be refreshed and the above-mentioned refreshing method, in the implementation process of the present invention, by partitioning the screen by rows or columns, the screen display mode of the MEMORY LCD screen can be set to three types, that is, the display mode with a higher partial refresh frequency corresponds to the first working mode of the handheld device, the display mode with a lower overall refresh frequency corresponds to the second working mode of the handheld device, and the display mode with a higher overall refresh frequency corresponds to the third working mode of the handheld device. For each screen display mode of the MEMORY LCD screen, the image frame data of the screen display mode (that is, which icons and which detection quantities and their position information need to be displayed on the screen in each working mode) are pre-stored in the memory 2.

[0055] The first working mode is a commonly used working mode for handheld devices. The screen display mode of the MEMORY LCD screen 200 corresponds to the first working mode by default (for example, a mode for collecting and displaying current physical values ​​such as pressure, temperature, humidity, etc.). After the program is started, the processor 1 transfers the image template data stored in the ROM to the memory (RAM).

[0056] Based on the above configuration, the screen refresh method for the handheld device includes the following steps (see Figure 3 ):

[0057] A first image data acquisition step, acquiring a screen display mode of a current MEMORY LCD screen and first image data corresponding to the screen display mode, and storing the data in a first cache unit;

[0058] A second image data acquisition step, acquiring features of the image data to be refreshed corresponding to the screen display mode, acquiring the image data to be refreshed from the first cache unit, and setting a header in front of each row or column of the image data to be refreshed, generating second image data, and storing the second image data in a third cache unit; wherein the features of the image data to be refreshed at least include position information of the image data to be refreshed (i.e., row information or column information of the image data to be refreshed, the position information of the data to be refreshed corresponds to a specific screen display mode and is preset by a user), and the header at least includes a row number or a column number of the image data to be refreshed;

[0059] In the screen refresh step, the DMA controller sends the second image data stored in the third cache unit to the LCD driving module of the MEMORY LCD screen through the transmission bus, so that the screen is refreshed.

[0060] The screen refresh method for a handheld device of the present invention is described in detail below in conjunction with specific embodiments and drawings. In the following description, different "one embodiment" or "embodiment" does not necessarily refer to the same embodiment. In addition, the specific features, structures, or characteristics in one or more embodiments may be combined in any suitable form. Example

[0061] The following describes the screen refresh process of the MEMORY LCD screen using a handheld pressure calibrator as an example (see Figure 3 ):

[0062] In the first image data acquisition step, the screen display mode of the current MEMORY LCD screen 200 and the first image data corresponding to the screen display mode are acquired and stored in the first buffer unit 21 of the memory 2 .

[0063] Specifically, the processor 1 identifies the current screen display mode of the MEMORY LCD screen 200 by acquiring the screen display mode status identifier sent by the MEMORY LCD screen 200 .

[0064] The processor 1 obtains the pressure signal from the external device (pressure acquisition module) through the communication interface 5, processes it and puts it into the corresponding memory, then retrieves the icon display position data and image data corresponding to the first working mode display frame and the pressure display position data and image data from the memory, and encapsulates them into the first image data (including the image data displayed on the entire screen) and stores them in the first cache unit 21. The first cache unit 21 is used to store the full-screen image display frame data corresponding to a certain working mode. Each storage bit in the first cache unit 21 corresponds to each pixel of the MEMORY LCD screen. Taking the MEMORY LCD screen with a resolution of 480×640 as an example, the 1st to 480th bits of the first cache unit 21 correspond to the first row of pixels of the MEMORY LCD screen, and the 481st to 960th bits correspond to the second row of pixels of the screen, and so on; when it is necessary to refresh the image data of a specific row, it is only necessary to obtain the image data of the corresponding position from the first cache unit 21.

[0065] The second image data acquisition step specifically includes the following steps:

[0066] a first refresh position data acquisition step, acquiring display position data of the pressure image data as first refresh position data, and storing the data in the second cache unit 22;

[0067] The second image data generating step obtains the row number or column number of the current pressure image data from the second cache unit 22, and obtains the image data corresponding to the row number or column number from the first cache unit 21, and adds the row number in front of each row of image data, or adds the column number in front of each column of image data, generates the second image data, and stores it in the third cache unit 23.

[0068] Specifically, an example storage format of the first refresh position data is (starting row number or column number, ending row number or column number), wherein the starting row number or column number corresponds to the starting row position or column position of the pressure image data displayed on the entire screen, and the ending row number or column number corresponds to the ending row position or column position of the pressure image data displayed on the entire screen. In this embodiment, the first working mode is a preset mode, wherein the display position of the pressure image data on the entire screen is fixed, therefore, the display position data of the pressure image data is fixed and pre-stored in the memory 2 along with the first working mode display frame, the display position data of the pressure image data therein is retrieved and stored in the second cache unit 22 as the first refresh position data; another method for obtaining the first refresh position data may also be, when storing the current first image data in the first cache unit 21, comparing the image data stored in each storage bit (i.e., the previous first image data) with the image data to be stored (i.e., the current first image data), recording the storage position of the inconsistent image data, determining the corresponding row number or column number based on its storage position, and storing the determined row number or column number in the second cache unit 22 as the first refresh position data.

[0069] The format of the second image data is LineM+image display data, Line(M+1)+image display data, ..., LineN+image display data, where M and N correspond to the starting row number and ending row number or the starting column number and ending column number in the first refresh position data respectively.

[0070] Preferably, the first refresh position data acquisition step further includes the following steps:

[0071] Determine whether the value of the pressure data acquired last time is consistent with the value of the pressure data acquired currently. If they are consistent, the corresponding first refresh position data is set to zero. At this time, when executing the second image data generation step, since the first refresh position data is zero, the image data of the zeroth row / column acquired from the first cache unit 21 is empty, that is, there is no image data of the zeroth row. Therefore, the image data acquired from the first cache unit 21 is empty, and correspondingly, the second image data is also empty. Then, in the screen refresh step, the DMA controller detects that there is no data to be transmitted in the third cache unit 23. Therefore, there is no need to perform data transmission operations.

[0072] In the screen refresh step, the DMA controller 3 sends the second image data stored in the third cache unit 23 to the LCD driving module 201 of the MEMORY LCD screen 200 through the transmission bus, so that the screen is refreshed.

[0073] Furthermore, the refresh mode of the MEMORY LCD screen 200 is periodic refresh, real-time refresh or a combination of periodic refresh and real-time refresh, wherein periodic refresh is refreshed with a fixed refresh cycle. If multiple sets of pressure data are collected within one refresh cycle, the last set of data is generally used as the image display data for display; real-time refresh means that the refresh can be performed at any time according to certain conditions or requirements. The triggering condition of the real-time refresh is usually the real-time refresh caused by the screen operation, or the refresh caused by receiving the instruction of the host computer or other equipment through the communication interface.

[0074] To avoid frequent partial refreshes, the solution for combining periodic refreshes with real-time refreshes is as follows:

[0075] After executing a real-time refresh, the time of the real-time refresh is used as the starting time of a new refresh cycle, and the refresh cycle is re-timed.

[0076] For example, set the refresh cycle to 300ms, the pressure collection cycle to 100ms, and the start time to 0ms. If a real-time refresh is performed at 205ms, the refresh cycle will be re-timed at 205ms, that is, the next cycle refresh is not performed at 300ms, but at 505ms. Example

[0077] From the data perspective, the difference between color image data and black-and-white image data lies in the different number of bits. A single pixel of black-and-white image data only requires 1 bit, while color image data requires multiple bits, such as 8 bits, 16 bits or 24 bits. The present invention configures the screen display color according to the three working modes of the handheld device. For example, the display mode corresponding to the first working mode is a mixed display of black-and-white and color, that is, the rows or columns where the area with a higher refresh frequency is located are displayed in black and white, and other areas are displayed in color. In the second working mode, since the overall refresh frequency of the screen is low, color display is used to enhance the display effect of the picture. In the third working mode, since the overall refresh frequency of the screen is high, black-and-white display is used to reduce the pressure of bus data transmission.

[0078] In order to realize partial refresh of the screen image, different color configurations are adopted for different screen display modes. For example, the first working mode is black and white mixed color display. Figure 2 , the screen refresh process of the MEMORY LCD screen is as follows:

[0079] The first image data acquisition step is to acquire the screen display mode of the current MEMORY LCD screen 200 , acquire the first image data corresponding to the screen display mode, and store the first image data in the first buffer unit 21 of the memory 2 .

[0080] The second image data acquisition step specifically includes the following steps:

[0081] A first refresh position data and first color position data acquisition step, acquiring the position data of the pressure image data as the first refresh position data, and storing it in the second cache unit 22; acquiring the position data displayed in black and white in the first image data as the first color position data, and storing it in the fourth cache unit 24;

[0082] The second image data compression generation step obtains the row number or column number of the image data to be refreshed (i.e., the pressure image data) from the second cache unit 22, obtains the row number or column number of the first image data displayed in black and white from the fourth cache unit 24, and obtains the image data to be refreshed corresponding to the row number or column number of the first refresh position data from the first cache unit 21, performs image data compression processing on the row or column corresponding to the first color position data in the image data to be refreshed, and combines the black and white color identifier with the row number or column number of the first refresh position data into a header, which is placed in front of the image data in the row or column, generates the second image data, and stores it in the third cache unit 23.

[0083] Specifically, the first image data acquired in the first image data acquisition step stores one pixel data in 8 bits, for example, black is represented as "00000000" and white is represented as "11111111". In the first refresh position data and first color position data acquisition step, the position pixel corresponding to the row or column displayed as black or white in the first refresh position data is compressed from 8 bits to 1 bit, which helps to reduce the bus data transmission pressure. In this step, the purpose of storing the first color position data is to store the row number or column number of the black or white area on the screen to indicate the row number or column number of the area that needs to be compressed.

[0084] Specifically, the format of the second image data generated in the second image data compression generation step is "header + image data", for example, the header is 16 bits, and for a specific row or column, the first six bits indicate the color of the image display, "000001" indicates black and white (1 bit), and the last ten bits indicate the row number or column number, and each pixel in the image data following the header is compressed to 1 bit, that is, "00000000" is compressed to "0", and "11111111" is compressed to "1"; and for rows or columns displayed in color, the first six bits of the header indicate the color of the image display, "001000" indicates color (8 bits), and the last ten bits indicate the row number or column number, and the image data following the header is not compressed.

[0085] In the screen refresh step, the DMA controller 3 sends the second image data stored in the third cache unit 23 to the LCD driving module 201 of the MEMORY LCD screen 200 through the transmission bus, so that the screen is refreshed.

[0086] Specifically, in the screen refresh step, when the MEMORY LCD screen 200 receives the second image data, it identifies and reads the subsequent image data according to the header part. For example, the second image data includes the first color line (header part) + color image data (each 8 bits represents a pixel) + the second black and white line (header part) + the black and white image data (each 1 bit represents a pixel) + the third color line + the color image data. The MEMORY LCD screen 200 first reads the first 2 bytes of the entire data according to the header reading method, determines the row number and the image data type, and then reads the subsequent data according to the color data type (8 bits per pixel) and converts them into a unified display data format. Since the number of pixels on the screen is fixed, the image data reading of one line is completed just when the first line of color image data ends. The MEMORY LCD screen 200 determines that the image data reading of one line has been completed, and reads the next 2 bytes of data (i.e., the second black and white line) again according to the header reading method, determines the row number and the image data type, and then reads the subsequent data according to the black and white data type (1 bit per pixel) and converts them into a unified display data format, and so on.

[0087] The screen refresh method of the present invention utilizes the characteristic of a MEMORY LCD screen having a pixel storage function, so that the display screen can display the currently displayed image without frequent refreshing, thereby saving resources and optimizing the display effect; based on the characteristic of the MEMORY LCD screen being refreshed in rows or columns, the method adopts a screen partitioning method by rows or columns, performs partial refreshing of the MEMORY LCD screen according to a refresh frequency preset for each area, and adopts a DMA method to transmit image data, thereby improving the screen refresh speed and reducing power consumption; further, the pixel color of each area is set according to the refresh rate preset for each area, the black and white image data is compressed, and the CPU data processing and data transmission are realized in parallel by setting a cache, thereby further improving the data transmission rate, reducing resource consumption, and thus reducing power consumption.

[0088] Those skilled in the art should understand that these embodiments or implementations are only used to illustrate the present invention but not to limit the scope of the present invention. Various equivalent variations and modifications made to the present invention belong to the disclosure of the present invention.

Claims

1. A screen refresh method for a handheld device, the handheld device comprising a processor integrated on an MCU mainboard, a storage, a DMA controller and a MEMORY LCD screen connected to the MCU mainboard signal, the MEMORY LCD screen having an LCD driver module therein, the LCD driver module being connected to the MCU mainboard via a transmission bus interface, characterized in that: The method comprises the following steps: A first image data acquisition step, in which the processor acquires the current screen display mode of the screen of the handheld device and the first image data corresponding to the screen display mode, and stores them in a first cache unit of the memory; In a second image data acquisition step, the processor acquires features of the image data to be refreshed corresponding to the screen display mode, acquires the image data to be refreshed from the first cache unit, and sets a header in front of each row or column of the image data to be refreshed, generates second image data, and stores the second image data in a third cache unit of the memory; wherein the features of the image data to be refreshed at least include location information of the image data to be refreshed, and the header includes at least a row number or a column number of the image data to be refreshed; In a screen refresh step, the DMA controller sends the second image data stored in the third cache unit to the LCD drive module of the screen of the handheld device through the transmission bus, so that the screen is refreshed; The characteristics of the image data to be refreshed also include color information of the image data to be refreshed, and the second image data acquisition step includes the following steps: The first refresh position data and first color position data acquisition step, the processor acquires the position data of the image data to be refreshed as the first refresh position data, and stores it in the second cache unit of the memory; acquires the position data displayed in black and white in the first image data as the first color position data, and stores it in the fourth cache unit of the memory; In the second image data compression generation step, the processor obtains the row number or column number of the image data to be refreshed from the second cache unit, obtains the row number or column number displayed in black and white in the first image data from the fourth cache unit, and obtains the image data to be refreshed corresponding to the row number or column number of the first refresh position data from the first cache unit, performs image data compression processing on the row or column corresponding to the first color position data in the image data to be refreshed, and combines the black and white color identifier with the row number or column number into a header, which is placed in front of the image data in the row or column, generates second image data, and stores it in the third cache unit.

2. The screen refresh method for a handheld device according to claim 1, characterized in that: The second image data acquisition step comprises: A first refresh position data acquisition step, when storing the current first image data in the first cache unit, comparing the first image data stored in each storage bit with the first image data to be stored, recording the storage position of the inconsistent image data, determining the corresponding row number or column number based on the storage position, and storing the determined row number or column number in the second cache unit as the first refresh position data; In the second image data generation step, the processor obtains the row number or column number of the currently refreshed image data from the second cache unit, and obtains the image data corresponding to the row number or column number from the first cache unit, and adds the row number in front of each row of image data, or adds the column number in front of each column of image data, generates the second image data, and stores it in the third cache unit.

3. The screen refresh method for a handheld device according to claim 2, characterized in that: The first refreshing position data acquisition step also includes the following steps: The processor determines whether the data content and state of the image data to be refreshed acquired last time are consistent with the content and state of the image data to be refreshed acquired currently, and if they are consistent, the corresponding first refresh position data is set to zero; When executing the second image data generating step, if the first refresh position data is zero, the image data obtained from the first cache unit is empty.

4. The screen refresh method for a handheld device according to claim 1, characterized in that: The image data compression process refers to compressing the image data pixel storage bits from multiple bits to 1 bit.

5. The screen refresh method for a handheld device according to any one of claims 1 to 4, characterized in that: The screen display mode includes three types, namely, a display mode with a higher refresh rate in a partial area corresponds to the first working mode of the handheld device, a display mode with a lower overall refresh rate corresponds to the second working mode of the handheld device, and a display mode with a higher overall refresh rate corresponds to the third working mode of the handheld device; The display mode corresponding to the first working mode is a mixed display of black and white and color, the second working mode uses color display, and the third working mode uses black and white display.

6. The screen refresh method for a handheld device according to any one of claims 1 to 4, characterized in that: The refresh mode of the MEMORY LCD screen of the handheld device is periodic refresh, real-time refresh or a combination of periodic refresh and real-time refresh, wherein the triggering condition of the real-time refresh includes the processor receiving a screen operation instruction or receiving an instruction from a host computer or other device through a communication interface.

7. The screen refresh method for a handheld device according to claim 6, characterized in that: The scheme of combining periodic refresh with real-time refresh is: After executing a real-time refresh, the processor uses the time of the real-time refresh as the starting time of a new refresh cycle and retimes the refresh cycle.

8. A handheld device, comprising an MCU mainboard and a MEMORY LCD screen, wherein the MEMORY LCD screen has an LCD driver module, and the LCD driver module is connected to the MCU mainboard via a transmission bus interface, wherein: The MCU mainboard includes: A first image data acquisition unit, used to acquire a current screen display mode of the screen of the handheld device and first image data corresponding to the screen display mode, and store the first image data in a first cache unit; a second image data acquisition unit, configured to acquire the image data to be refreshed from the first cache unit according to the characteristics of the image data to be refreshed corresponding to the screen display mode, and to set a header in front of each row or column of the image data to be refreshed, to generate second image data, and to store the second image data in a third cache unit; wherein the characteristics of the image data to be refreshed at least include the position information of the image data to be refreshed as the first refresh position data, and the header at least includes the row number or column number of the image data to be refreshed; An image refresh unit, used for sending the second image data stored in the third cache unit to the LCD drive module of the screen of the handheld device through a transmission bus, so as to refresh the screen; The second image data acquisition unit is further used to cache the position data displayed in black and white in the first image data as the first color position data; The second image data acquisition unit is used to obtain the row number or column number of the image data to be refreshed from the second cache unit, obtain the first color position data from the fourth cache unit, and obtain the image data to be refreshed corresponding to the first refresh position data from the first cache unit, perform image data compression processing on the row or column corresponding to the first color position data in the image data to be refreshed, and combine the black and white color identification with the row number or column number into a header, which is placed in front of the image data in the row or column, to generate second image data, and store it in the third cache unit.

Images