How to solve the abnormal reversal of industrial LCD screen display？
Date:2025-11-19
How to solve the abnormal reversal of industrial LCD screen display？
Abnormal display reversal of industrial LCD screens is often manifested as image up and down reversal, left and right reversal, etc. The problem is most likely due to hardware connection, driver configuration, or system parameter settings. You can gradually investigate and solve the problem in order from easy to difficult. The specific methods are as follows:
1. Check the basic hardware connections
This is the easiest surface issue to troubleshoot, prioritize operation. One is to check the FPC wiring. FPC wiring is commonly used in industrial LCD screens to transmit signals. If the wiring is inserted incorrectly, misplaced, or has poor contact, it will directly cause the display scanning sequence to be disordered and reverse. After cutting off the power, unplug the ribbon cable, check if pin 1 of the ribbon cable corresponds to pin 1 of the interface, clean the dust and oxide layer on the ribbon cable, and then plug it back in. The second is to detect the power supply and signal. Use an oscilloscope to measure whether the power supply voltage of the LCD screen meets the specifications (such as common 3.3V, 5V). At the same time, check the waveform of synchronization signals such as CLK and VSYNC. If there is signal interference, filter capacitors can be added to the power supply end or the signal line length can be shortened to reduce interference.
2. Adjust the system and driver basic settings
If the hardware connection is normal, you can start with the software surface configuration. If paired with an industrial screen of an industrial computer, the Windows system can right-click on a blank space on the desktop to enter "Display Settings", find the "Direction" option, and select "Normal" mode; You can also try using the shortcut keys Ctrl+Alt+up and down arrow keys to quickly adjust the display direction. If it is an NVIDIA, AMD or other independent graphics card, you can also open the corresponding graphics card control panel and find the screen rotation function in the display options to correct the inversion problem. In addition, some embedded systems of industrial equipment can view the startup script. If there are incorrect display direction configuration commands in the initialization code, corresponding instructions can be added to correct them.
3. Modify the register parameters of the LCD controller
The scanning direction of industrial LCD screens is mostly controlled by controller registers, which is the core software means to solve the inversion problem. The register addresses of different models of LCD screens are different. For example, the direction control register of ILI9341 is 0x36, and the relevant register of ST7789V is 0xB6. It is necessary to refer to the corresponding specification book to determine the target register. Afterwards, write parameters using I ² C or MIPI-DSI commands, such as writing the corresponding value to the 0x36 register of ILI9341, to switch between forward and reverse scanning and correct image inversion. After modification, the configuration can be verified for effectiveness by reading the register values.
4. Revise the core configuration of the driver program
If the above methods are ineffective, further adjustments to the driver code are required. In embedded systems, LCD driver files (such as panel simple. c) can be modified to adjust the synchronization signal polarity parameters of frame buffers, such as changing incorrect vertical synchronization polarity flags to match the type of LCD screen. At the same time, check the storage order of the video memory data. If the inversion is caused by the alignment error of the big end/small end data, adjust the storage logic of the pixel data in the frame buffer to ensure that the coordinate mapping is normal. After the modification is completed, recompile the kernel or driver module and load the test.
5. Investigate deep hardware faults
If all software operations are ineffective, it is highly likely that the hardware is damaged. On the one hand, the LCD screen module of the same model can be replaced for testing. If the new screen displays normally, the driver chip or internal pixel array of the original screen may be damaged; On the other hand, check the display interface circuit on the industrial control motherboard. If the interface chip is poorly soldered or damaged, it will cause abnormal transmission of control signals. Professional equipment should be used to detect and re solder or replace the chip.
TFT LCD:https://www.auo-lcd.com/
