With the continuous expansion of LED display applications, we have a certain basic knowledge of full-color LED display screen, laying the foundation for future use. The parameter setting of full-color LED display is the first step to use LED display. Now let’s take a look at the specific operation process.
&Main function analysis and model construction of full color LED display
Due to different manufacturers, the number of parameters of full-color LED display is also different, but basically each display has more than 20. After analysis and classification, it can be divided into three types: core parameters, basic parameters and auxiliary parameters.
(1) core parameters
&The core parameters are necessary for full-color LED display. If the settings are not correct, the lights will not be displayed and the screen will burn out. The core parameters include cascade direction, OE polarity, data polarity, LED display type, color, scanning mode, travel sequence and row order.
(2) basic parameters
&The basic parameters are the basic parameters of full-color LED display. If the settings are not correct, communication, non display or abnormal display will not work. The basic parameters include display width, display height, control card address, baud rate, IP address, port number, MAC address, subnet mask, gateway, LED display refresh frequency, shift clock frequency and blanking time.
(3) auxiliary parameters
Auxiliary parameters are parameters set for better display and control, including the name of control card, communication display mark, brightness and screen switching time.
&To sum up, more than 20 parameters need to be configured correctly for full-color LED display before lighting up, which is a tedious and complicated process. If the setting is not correct, the light will not be displayed, and the heavy object will burn the LED display screen, causing significant economic losses and construction delay. This is because the price of typical display screen is more than 1000 yuan, and some even exceed 1 million yuan. Therefore, from a prudent point of view, some LED control software is complicated and inconvenient to use, which is understandable. In order to overcome the shortcomings of the existing software, reduce the threshold, and make the hardware debugging of the display screen easy and natural, this paper establishes a complete display parameter configuration model and intelligent configuration model.
&For the configuration of basic parameters and auxiliary parameters, input box and selection box are provided. After user input and selection, the screen can be directly connected to the settings. The core parameters can be completed by professional quick check, intelligent configuration and external file configuration.
&Professional quick check
&For normal and ordinary full-color LED displays, their parameters are generally fixed. At this time, you can arrange them into a file or table, and debug options to load the configuration.
(2) intelligent configuration
&For uncommon or uncertain full-color LED displays, the parameters are unknown. At this time, the intelligent configuration can be used to determine the configuration parameters, and then save them for future use.
&Nbsp; & nbsp; (3) external file configuration
Import a configuration from an intelligent configuration or an external file that is otherwise built.
In the three core parameter configuration methods, intelligent configuration is the focus of this paper, and its main process and functions are as follows
(1) start intelligent configuration;
&(2) through the wizard, the user and the display screen can choose interactively 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 order of the points, determining the line order, and generating the configuration parameters;
(3) return the intelligent configuration parameters;
&4) connect LED display and set parameters;
&If it is correct, output the parameter operation;
(6) select an external file to save for later download. At this point, the intelligent configuration of the display is completed.
&Design and implementation of key functions
&Fill in the initial parameters
The whole intelligent setting process is completed by the display module. For full-color LED display, it is the first display module from the direction of signal cascade. That is, when the signal cascade direction is from left to right, the first display module is 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 is the display module in the upper right corner of the display screen. In order to facilitate observation, the general intelligent setting only needs one display module to set, and confirm that the display module is in good condition without fault (excluding abnormal lines or points).
&After selecting the display module, fill in the parameters such as signal cascade direction, module width point, module height point and display screen type, and click “next” to start intelligent configuration.
&Determine the polarity of OE and data
&OE polarity and data polarity are very important parameters of display screen, in which OE polarity determines whether the display is on, and data polarity determines whether the display is correct.
&If the OE polarity is not correct, the full-color LED display will not light up regardless of the polarity of the data; if the polarity of the data is not correct, the display is abnormal, and the display is on. Therefore, the first task of intelligent configuration is to determine the polarity of OE and data. The display module has three options: “all on”, “all black / all black”, “other display or irregular changes”.
&If you select “other display or irregular changes”, it indicates that there is a problem with the hardware configuration, and the hardware configuration needs to be corrected before intelligent configuration. In the specific design, 0 represents high level and 1 represents low level. High level and low level are sent in turn. The user selects on or off to determine the value of OE polarity and data polarity. Therefore, there are four combinations of OE polarity and data polarity. Therefore, it only takes four steps to determine the polarity of OE and data. The OE polarity value and data polarity value can be determined by sending the corresponding OE polarity value and data polarity value in turn and recording the user’s choice at each step.
&Determination of color
&There are three kinds of LED displays without grayscale: monochrome, bicolor and panchromatic. Monochrome usually corresponds to red. Two colors are usually red and green; full colors are usually red, green, and blue. For a monochrome screen, this step can be omitted; for a two-color screen, a red command is sent, and according to the color displayed, it can be judged whether the display is normal or red-green; for a full-color screen, red and green are sent respectively. According to the display color, you can judge whether the display is normal or red green, red blue or green blue.
2.4 determine scan mode
&The formula for judging the scanning mode is: module height / number of lit lines = scanning mode. In the design, the command is sent to judge the scanning mode. According to the number of bright lines selected by users, the scanning mode can be calculated by using the formula. Since the scanning mode has not been determined yet, the large denominator scanning mode determined earlier is adopted for data output, and the number of bright lines on the top is taken as the module height parameter.
&Determine the order of travel points
&In fact, the full-color LED display is displayed point by point in order, but it uses the time-delay characteristics of human vision to quickly send the images of all points on the screen at one time to achieve the update effect of full screen image display. Therefore, the order of these points must be determined before sending.
In order to get the order of travel points, you can send a point every other second and record its location to determine. The specific implementation method is as follows:
&2.5.1 send point command;
&The 2.5.2 display module lights up one LED pixel per second. Observe the lighting order of these pixels carefully. After confirming the lighting sequence, click the grid to track the points corresponding to the simulation display module diagram according to the lighting sequence (each grid of the simulation diagram corresponds to a pixel of the display module).
&Click “next” after 2.5.3, and the system will automatically record the order of points.
In order to help users determine the order of the points, the system also provides the functions of restore, rewind, reset and inference.
2.6 determine the row order
In addition to the order of highlighting, you need to determine the order of the highlighted rows. To get the row order, you can send a line at one second intervals, send a point for each line, and then record its position. The specific implementation method is as follows: after sending the line display command, observe the lighting sequence of LED lights on the display driver board, and track the corresponding sequence points to the relative position of the line sequence. When you are finished, click next, and the system will automatically record the row order.
For ordinary LED display screen, the line sequence can be determined through the section “2.5 determining the sequence of running points”. This step can be omitted. At the same time, in order to help users determine the order of rows, the system also provides the function of re entering rows or rows
Download parameters and complete intelligent configuration
&After the above parameters are determined, reorganize the order and format according to the display data configuration format, and then download to the display screen 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 future use; if it is not correct, analyze the reasons and then conduct intelligent configuration again.