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▊ IP Settings Two IP configuration methods: (1)Set a default static IP; (2)Set a temporary static IP ( it is disabled after power cycling). 1. Static IP settings (1) Open /etc/network/interfaces and modify the configuration vi /etc/network/interfaces As follows, configure eth0 as static and eth1 as dynamic: (2) DNS settings Open rc.local with the command vi /etc/rc.local and add the following to it: echo "nameserver 8.8.8.8" > /etc/resolv.conf (3) Block information update&restart sync reboot 2. Temporary network settings Alternatively, the commands can be used temporarily to set the IP and gateway. However, please note that this method's configuration will be lost after a restart. ▊ Adding Startup Auto-run Content 1. Adding the following to the startup script Enter vi /etc/rc.local As an example of booting with the output ''hello world,'' add the following content: Note: Add the startup auto-run content before exit 0; 2. Adding startup auto-run items To create a startup auto-run item in the /etc/rc5.d/ directory vi /etc/rc5.d/S99test.sh As follows: #!/bin/bash echo "helloworld!" chmod 777 /etc/rc5.d/S99test.sh S99 indicates the startup priority as 99, which can be adjusted by the user based on demand. 3. Power-on self-starting 4G dialing method Previously it was mentioned that startup applications can be directly added to /etc/rc.local. However, 4G slightly differs from other applications because it uses a separate 4G module that requires initialization time. Based on practical tests, the 4G module takes 3-5 seconds after startup to function properly. Therefore, before initiating 4G dialing, a delay of 3-5 seconds is necessary. Modify as follows: vi /etc/rc.local Add the following: Note: The delay time cannot be less than 3s. ▊ WiFi 1. Static IP Settings (WiFi) WiFi login script: /usr/bin/fltest_cmd_wifi.sh The second-to-last line of the script assigns a dynamic IP to wlan0. If there is a need to set a static IP, it can be done as follows: 2. Power-on self-starting settings (WiFi) Also put the WiFi script in the/etc/rc.local. In this case, it is necessary to add an ''&'' symbol at the end to run the script in the background. Otherwise, it might block and prevent access to the file system. ▊ Boot 1. SSH connection failure (1) When SSH cannot connect, check if ping is possible. If ping fails, it could be due to network issues. The computer and the device should be on the same subnet. The default IP for eth0 is 192.168.0.232. Users can directly connect them or connect both to the same router. Then, set a 192.168.0 subnet IP on the computer; (2) If ping is successful, first confirm whether the factory image can connect normally. If the factory image can connect normally, check what services are starting up at boot causing the issue; ensure that services starting at boot are backgrounded. Failure to do so may cause process blocking, preventing SSH login. Consider reflashing the factory image if necessary; (3) Ensure that the board's IP address is being pinged. This can be tested by unplugging the Ethernet cable and then pinging from the computer.

Display is one of the most crucial functions of embedded development board, and being able to support a greater variety and higher specifications display interface, means it can cater to a wider range of usage scenarios. Before leaving the factory, each embedded development board undergoes screen debugging. However, during the customer’s project development process, they may encounter compatibility issues when adapting to non-original screens. Taking the Folinx Embedded AM62x series OK6254-C development board as an example, it features two display interfaces: LVDS and RGB. It can support up to 2 display controllers and simultaneously output two different screens. This article describes in detail the display scheme of the OK6254-C development board - how RGB is displayed and modified. 1. RGB Interface Specification The embedded OK6254-C development board provides one 24-bit RGB parallel display interface and supports a maximum resolution of WUXGA (1920x1200 @60fps, 165MHz pixels). The 16 bit data interface is led out from the carrier board through the FPC seat, which is suitable for the embedded 7-inch resistance and capacitance touch screen of Forlinx by default, with a resolution of 1024 x600 @ 60 FPS. If high color detail and realism are required, RGB888 is a better choice. If storage space is limited and there is no high requirement for color representation, then using RGB565 can be considered to save storage resources. At this point, the selection of RGB888 and RGB 565 is involved. 2. Selection and Modification of RGB888 and RGB 565 The modification of OK6254-C device tree is very convenient. We divide the device tree into three parts: kernel device tree, LVDS display device tree and RGB display device tree. To make RGB888 and RGB565 selections and modifications, we need to open the OK6254-C-rgb.dts file as shown below: In the first red box in the image above, we can modify the RGB display to RGB888 or RGB565, the default is rgb565. The default resolution of the red box at the bottom is 1024*600, which can be modified manually by following the screen manual. The maximum resolution supported is 1920x1200. In addition, the OK6254-C development board also supports 800 * 480 screen resolution, the next step is to introduce the screen selection operation. Open OK6254-C-rgb-800_480.dts You can modify the resolution and the screen parameters suitable for the screen in the red box section of the picture below: (1) Compile: Because we only modify the device tree, we don't need to compile it all, which is not only time-consuming but also laborious. After compiling the kernel, a new Image and multiple device tree files will be generated in the images directory. Here we only need to compile the kernel separately. Switch directory: cd OK6254-linux-sdk/ Execute the environment variable:. build.sh Execute instructions to compile the kernel separately: sudo ./build.sh kernel Package all the device tree files and replace them in the /boot/ directory of the board, then sync to save and reboot. scp images/OK6254-C* [email protected]:/boot/ Modification is finished here. (2) Screen Selection Stage: We have modified the corresponding file. How should we select the screen after replacing it? At present, there are three kinds of screen-switching control methods: kernel device tree designation, Uboot menu dynamic control, Forlinx Desktop interface and Uboot menu application. Today, I will briefly introduce the dynamic control of Uboot menu. During Uboot, pressing the space bar will take you to the Uboot menu. There are three options in the menu: Enter 0 to enter uboot Command the line; Enter 1 to restart Uboot; Enter 2 to enter the Display Configuration menu. There are three options in the menu: Enter 0 to return to the previous menu; Enter 1 will toggle what option 1 displays to configure Screen 1 LVDS; Note: Screen 1 supports single LVDS, dual LVDS, and off (i.e., LVDS off) Enter 2 to toggle the display of option 2 to configure the Screen 2 LCD. Note: Screen 2 supports 1024 * 600 resolution LCD screen, 800 * 480 resolution LCD screen and off (i.e. RGB off) When selecting the LCD screen, we enter 2 and it's OK. After selecting the desired configuration, enter 0 to return to the previous menu level. Restart Uboot or enter the command line to start the system, which can make the screen settings take effect. For other resolution screens, please modify the kernel device tree screen parameters according to the screen parameter requirements. So far, we have finished the introduction of RGB display scheme. Of course, other display interfaces are similar. You can pay attention to the follow-up Application Notes. Originally published at www.forlinx.net.