Design and implementation of intelligent configuration of LED display screen

introduction

In recent years, with the rapid development of the LED industry, there are many display models and specifications, which give users more choices and make the display effect of LED display more colorful. However, too many models and specifications bring some problems in engineering applications. Due to the large number of manufacturers and the lack of unified standards, the installation and debugging of LED display screens has become a very arduous task. In addition, installation and debugging involve more than 20 parameters, which are very demanding and can generally only be completed by professional technicians. In fact, most of the installation and debugging are repetitive work, which makes many professional technicians fall into the debugging of various engineering sites, resulting in a huge waste of manpower. Therefore, some people have proposed whether it is possible to debug in advance and form data files, so that professional technicians do not need to go to the site, and general engineering personnel can complete the debugging by downloading on site, so LED intelligent configuration technology came into being. After market research, some LED control software also realizes the function of intelligent configuration, but the effect is not ideal, such as too many steps, unintuitive, complicated, etc. Based on this, after research, this paper proposes a method of intelligent configuration, which allows users to make choices only through the "next step". At least seven steps are required to automatically complete the intelligent configuration, debug successfully, and generate data files for storage and download.

1 Main functional requirements analysis and model construction

The number of parameter items for display screens varies from manufacturer to manufacturer, but basically each display screen has more than twenty items. After analysis and classification, they can be divided into three types: core parameters, basic parameters and auxiliary parameters.

(1) Core parameters

Core parameters are necessary parameters for display screens. If they are not set correctly, the display may not be displayed at best, or the screen may be burned in at worst. Core parameters include cascade direction, OE polarity, data polarity, display screen type, color, scanning mode, dot sequence and row sequence, a total of 8 items.

(2) Basic parameters

Basic parameters are the basic parameters of the display screen. If they are not set correctly, communication will fail, the display will not be displayed, or the display will be abnormal. Basic parameters include display screen width, display screen height, control card address, baud rate, IP address, port number, MAC address, subnet mask, gateway, display screen refresh frequency, shift clock frequency and line blanking time, a total of 12 items.

(3) Auxiliary parameters

Auxiliary parameters are set for better display and control, including control card name, communication display mark, brightness, and screen on/off time, a total of 4 items.

In summary, a display screen needs to correctly configure more than 20 parameters before it can light up. Its tediousness and complexity can be imagined. If the settings are incorrect, the display screen will not display at best, or even burn out at worst, causing significant economic losses and delays in construction. This is because the price of general display screens is more than 1,000 yuan, and some even cost more than one million yuan. Therefore, it is understandable that some LED control software is complex in design and inconvenient to use for the sake of caution and safety. In order to overcome the shortcomings of existing software, lower the threshold for use, and complete the hardware debugging of the display screen in an easy and natural process, after research, this paper constructs a complete display screen parameter configuration model and intelligent configuration model, as shown in Figures 1 and 2.

In Figure 1, input boxes and selection boxes are provided for the configuration of basic parameters and auxiliary parameters. After the user inputs and selects, the display screen can be directly connected for setting. For core parameters, three methods can be used: professional quick check, intelligent configuration, and external file configuration.

(1) Professional Quick Search

For common and commonly used display screens, their parameters are generally fixed. In this case, you can organize them into files or tables in advance and choose to load the configuration during debugging.

(2) Intelligent configuration

For uncommon or uncertain display screens, whose parameters are unknown, intelligent configuration can be used to determine the configuration parameters, which can then be saved for later use.

(3) External file configuration

Import external files built by smart configuration or other means into the configuration.

Among the three configuration methods of core parameters, intelligent configuration is the focus of this article. Its main processes and functions are as follows:

(1) Start intelligent configuration;

(2) Through the wizard, the user and the display screen can make human-computer interaction choices and start the intelligent configuration operation. The core parameters are determined by filling in the initial parameters, determining the OE polarity/data polarity, determining the color, determining the scanning mode, determining the point sequence, determining the row sequence, and generating configuration parameters.

(3) Return intelligent configuration parameters;

(4) Connect the display screen and set parameters;

(5) If correct, perform output parameter operation;

(6) Select an external file and save it for later download. At this point, the intelligent configuration of the display is completed.

2 Design and implementation of key functions

2.1 Fill in initial parameters

The entire intelligent setting process is operated for the display module. For the display screen, to be precise, it is to observe the first display module entering from the signal cascade direction. That is, if the signal cascade direction is from left to right, the first display module refers to the display module in the upper left corner of the display screen. If the signal cascade direction is from right to left, the first display module refers to the display module in the upper right corner of the display screen. For the convenience of observation, generally only one display module is taken for setting during intelligent setting, and it is confirmed that the display module is in good condition and has no faults (including no abnormal display of rows or points).

After selecting the display module, fill in parameters such as signal cascade direction, module width points, module height points, display type, etc., and click "Next" to start intelligent configuration.

2.2 Determine OE polarity and data polarity

OE polarity and data polarity are extremely important parameters of the display screen. OE polarity determines whether the display screen is bright, while data polarity determines whether the display is correct. If the OE polarity is incorrect, the display screen will not be lit, no matter what the data polarity is; and if the data polarity is incorrect, the display is abnormal and all bright. Therefore, the first task of intelligent configuration is to determine the OE polarity and data polarity. The display module has three options: "all bright", "all black/dark bright", and "other displays or irregular changes". If "other displays or irregular changes" is selected, it means that there is a problem with the hardware configuration. The hardware configuration needs to be corrected before intelligent configuration. In the specific design, 0 represents high level and 1 represents low level. The values ​​of OE polarity and data polarity are determined by sending high and low levels in turn, and the user chooses to light up or not. In this way, there are 4 combinations of OE polarity and data polarity. Therefore, it only takes 4 steps at most to correctly determine the OE polarity and data polarity. As long as the corresponding OE polarity and data polarity values ​​are sent in turn and the user's selection at each step is recorded, the values ​​of OE polarity and data polarity can be determined.

2.3 Determine the color

Non-grayscale display screens are divided into three types: monochrome, dual-color and full-color. Monochrome generally corresponds to red; dual-color generally corresponds to red and green; full-color generally corresponds to red, green and blue. For monochrome screens, this step can be omitted; for dual-color screens, send a red command, and according to the displayed color, you can judge whether it is normal display or red and green inversion; for full-color screens, send red and green colors respectively, and according to the displayed color, you can judge whether it is normal display or red and green inversion, red and blue inversion, or green and blue inversion.

2.4 Determine the scanning method

For the scanning mode, the judgment formula is: module height / number of lit rows = scanning mode. During design, a command to judge the scanning mode is sent, and the scanning mode can be calculated using the formula according to the number of lit rows selected by the user. Since the scanning mode is not determined, data is output according to the high denominator scanning mode determined in the early stage, and the number of lit rows is capped at the module height parameter.

2.5 Determine the order of movement

The LED display screen actually displays in a dot-by-dot sequence, but it uses the delay characteristics of human vision to achieve the effect of updating the full-screen image display by quickly sending the image of all dots on the full screen at one time. Therefore, the order of dots must be determined before sending.

In order to obtain the point order, you can send a point at an interval of one second and then record its position. The specific implementation method is as follows:

(1) Send a dot-marking command; (2) One LED pixel on the display module will light up every second. Carefully observe the lighting order of these pixels. After confirming the lighting order, you can use the mouse to click on the corresponding position of the simulation display module diagram (each square in the simulation diagram corresponds to a pixel of the display module) according to the lighting order to draw points; (3) After completing the dot-marking, click "Next" and the system will automatically record the dot-marking order.

In order to better help users determine the order of points, the system also provides functions such as re-pointing, rollback, reset and deduction.

2.6 Determine row order

In addition to the order of bright spots, the row order of bright spots must also be determined. In order to obtain the row order, you can send a row at an interval of one second, send a dot in each row, and then record its position to determine it. The specific implementation method is as follows: After sending the row display command, observe the lighting order of the LED lights on the display driver board, and draw points in the corresponding order at the relative position of the row order. After completion, click "Next" and the system will automatically record the row order.

For display screens of common specifications, the row sequence can be determined through section "2.5 Determine the row sequence", and this step can be omitted. At the same time, in order to better help users determine the row sequence, the system also provides functions such as re-sequence, rollback, and reset.

2.7 Download parameters and complete intelligent configuration

After the above parameters are determined, reorganize the order and format according to the display data configuration format, then download it to the display configuration, and then observe whether it is correct. If it is correct, the intelligent configuration is completed. In addition, if necessary, it can be saved to a file for later use; if it is incorrect, analyze the cause and re-configure the intelligent configuration.

3 Conclusion

This paper implements a method of intelligent configuration of LED display screens through wizard-style, user selection status, automatic judgment and other methods, and applies it in LED navigator software, which has been well received by users. Practice has proved that this method can help users quickly configure and light up the display screen, while lowering the threshold for display screen installation and debugging, freeing professional technicians from engineering installation. In the future, technicians do not need to go to the site, and ordinary engineering personnel can complete the corresponding work by simply downloading the corresponding data files without repeated debugging.