LED display and computer connection method steps

LED display has obviously become the leader of display devices. Whether it is outdoors or indoors, led displays have occupied a large market. Maintenance personnel need to know the maintenance knowledge of LED display more comprehensively. The following is the screen. The method steps for connecting with a computer are hopefully helpful to everyone.

1, the main functional requirements analysis and model construction

For a direct network connection, connect the PC to the display using a direct network connection, and then manually set their IP addresses on the same network segment to communicate.

However, in this way, if you do not know the IP address of the LED display in advance, it will be difficult to communicate. In order to achieve the purpose of achieving direct communication between the PC and the display without knowing the display IP address, the principle of DHCP service can be used to solve the problem: that is, setting the LED display as a DHCP server with a fixed IP address and setting the PC network card as automatic To obtain the IP address, the IP address of the network adapter of the PC is automatically configured through the DHCP service function. In this way, the network connection channel is established. Some developers use this method to implement direct network connection. However, there are some problems with this method. First, because UDP communication is not connected to the communication, its communication reliability is worse and it is easy to fail. Second, it can only be passed. The operating system of the operating system is complete without intervention. The user cannot set the timeout. Sometimes the waiting time is too long, and the maximum is 60 seconds. Third, DHCP is a fixed IP mode. It is obviously not very good in practical applications. In the system, the original network card configuration information of the PC cannot be restored.

Based on this, after researching, this paper proposes a new method of network direct connection, which can realize the functions of direct network connection, automatic acquisition of IP addresses and storage and recovery of PC network card configuration information, overcoming the shortcomings of current implementation methods and improving reliability. The performance, stability, and timeliness of performance in all aspects, the system model shown in Figure 2, the main functions and workflow are as follows:

(1) When the system is started, all the network cards of the PC are retrieved and accessed, and its network card configuration information is saved for recovery when the system is exited;

(2) Start the network direct connection process;

(3) broadcast IP address request data packet;

(4) Return IP address data packet;

(5) Unpack, obtain the IP address of the PC and LED display, and set the IP address of the PC;

(6) Return to the IP address of the LED display, close the network directly and complete the establishment of the communication channel;

(7) After setting up the communication channel between PC and LED display, you can read/write parameters, send programs, switch screens and other communication control operations on the display screen;

(8) When exiting the system, restore the original state of the PC network card according to (1) the saved network card configuration information.

In the above process, (2)-(6) are the core process. It simulates the DHCP service, implements a PC broadcast request IP address, obtains a PC IP address and settings, uploads the LED display IP address, and completes the network direct connection. The establishment is a must-do when performing network direct connection operations; (1) and (8) are operations for saving PC network card configuration information and restoring network card configuration information when starting and exiting the system; (7) completing the network The general operation of the display control after directly connecting the channel

2. Design and implementation of key functions

2.1 Saving PC Network Card Configuration Information

The PC used to debug the LED display is usually a multi-purpose machine. While debugging the display, it is also used for office and Internet access. The IP address of the network card may be fixed or obtained automatically. When doing direct network connection, it may change its IP address. In order not to affect the user's work, it needs to automatically recover its IP address when exiting. To achieve this, when you start the LED control software, you can read the current network card configuration information, such as the IP address, network card name, MAC address, network card type, whether it is automatically configured IP address, etc., and put this information into a Stored in the linked list, set an identifier at the same time, record whether the user used the network direct connection during debugging the display screen and use it when exiting the system.

In the Windows operating system, you can use the IP Helper interface to read the network card information. It is an API for managing local network settings. By using the IP_ADAPteR_INFO structure, you can easily extract the above network card configuration information and save it to the linked list.

2.2 Learning from the Principle of DHCP Service, Constructing a Network Direct Connection Channel

To achieve direct network communication between the PC and the LED display, two key issues must be resolved: first, let the PC and the LED display be in the same network segment; and second, know the IP address of the LED display.

In addition, we must also solve the phenomenon of multiple network cards and wireless network cards that directly interfere with the network. Based on the principle of DHCP, the main solutions are as follows:

(1) Design a network direct connection control process on the PC; (2) When the network connection is required, start the process, determine the non-wireless network card connected to the LED display screen through the Windows related network API functions and registry information, Place its MAC address in the UDP packet of the build request IP address, broadcast it, and start the internal UDP packet capture sub-process; (3) After the LED display receives the UDP packet of the request IP address, according to its own IP address, Construct a PC's IP address and broadcast it. In order not to cause confusion, a pseudo DHCP packet is constructed here. When a normal Windows client receives the UDP packet, it will not automatically change its IP address. (4) After the UDP packet capture subprocess of the network direct connection control process receives the UDP packet of the assigned IP address, it unpacks the IP address of the PC and the IP address of the LED display; (5) Set the IP address of the PC network adapter and upload the LED. The IP address of the display screen is given to the control software. After the success, the network direct connection control process is closed and the establishment of the network direct connection channel is completed.

The process of direct network connection involves three systems: (1) Network direct connection control process. It constructs a UDP packet requesting an IP address and broadcasts it. At the same time, it monitors port 68 of the target network card, captures the returned UDP data packet, and parses out the PC. IP address of the machine and the IP address of the LED display, then set the IP address of the PC, submit the IP address of the LED display to the main process to complete the network direct connection task; (2) LED display DHCP service subprocess, It receives a PC's IP address request, builds and sets its own IP address, and returns a pseudo DHCP packet of the PC's IP address; (3) LED control software, when the user selects the network direct connection mode, it starts the network direct connection controller. Process, Implementation Network 2.3 Restoring PC Network Card Configuration Information

When exiting the system, check whether the network directly connected ID is saved according to 2.1. If you have not used the network direct connection method, you do not need to perform the network IP recovery function; otherwise, you will need to perform the recovery function, restore the 2.1 saved network card configuration, and recover. The network card IP address can use the netsh interface ip set command. At the same time, in order to speed up the processing speed and increase the success rate, you can follow the steps to disable the network card, set the network card IP address, and then enable the network card:

(1) Use the SetupAPI API interface function of Windows to disable the target network card;

(2) restore the target network card IP settings, according to the static IP address and dynamic IP address, respectively, with different commands:

a. Restore the static IP address command.

a. Restore Static IP Address command

Netsh interface ip set address name="Local Area Connection"

Source=STatic addr=192.168.1.19 mask=255.

255.255.0 gateway=nONe

b. Restore dynamic IP address commands.

Netsh interface ip set address "local connection" dhcp

(3) Use the SetupAPI related interface API function to enable the target network card