Currently, many display devices use LCD screens, and during the usage process, one may occasionally encounter a situation where the screen is blank and not displaying anything. Have you ever delved into the reasons behind this phenomenon and how to resolve it? Let’s briefly introduce it below!
Basic Background
1. Corresponding Product Type
Microcontroller interface TFT LCD / monochrome LCD module, specifically referring to single-chip microcontroller interface LCD display products.
2. What is a Blank Screen?
A blank screen refers to a state where the LCD display turns blank under suspected external interference; the system is still functioning normally during this state. Powering off and restarting or resetting the system can restore normal operation.
3. Why Does a Blank Screen Occur?
A blank screen is usually a state of turning off the display, and it is also the default reset/start state of the LCD display module. When the LCD display module receives a restart command or reset signal, it returns to the default state, resulting in a blank screen.
Possible Causes and Solutions for LCD Blank Screen
1. Reset Signal of LCD Display Module is Floating
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In design, the module’s input ports should not be left floating; the reset signal is also an input port. It is best to connect the relevant interfaces to the microcontroller for direct control.
2. Poor Interface Connection
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Attention should be paid to the reliability of signal connections.
3. Host Misissues Reset Signal, Reset Command, or Turn Off Display Command
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It is necessary to trace the program flow to identify critical points.
4. Related Blank Screens are Usually Found During Interference Testing (e.g., Electrostatic Discharge (ESD) Testing)
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In general product design, display modules are set at the front of the product; external ESD can expose the display module to the relevant electric field; the interference may not directly affect the signal or reset. However, related interference can easily affect 0V or power supply, causing the LCD display module to misjudge signal voltage; shortening the wiring distance between the host and display module can have a certain effect, and adding resistors/capacitors to the reset signal connection can also improve the situation. (Reference values: R=100R, C=0.01uF)
5. Other Solutions
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In the face of potential unknown interference on-site, it is recommended to periodically refresh the display content and related screen initialization settings to improve/restore display anomalies caused by interference;
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When the interface menu jumps back to the “Home” page, it is generally a full-screen refresh; consider re-initializing the related screen settings during this process to ensure the display module is set correctly;
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Consider that the default for reset is “turn off display”, and the microcontroller can also periodically read back the display status to check if the LCD display module is in a normal display state; if abnormalities are found, the host can issue a hard reset to reinitialize the LCD display module and refresh the display content to ensure normal display.
Conclusion
The LCD display module is a device that obeys the commands and signals it receives; it does not have the ability to determine the correctness of the relevant inputs. Good power supply and reasonable wiring layout are fundamental for good display; software monitoring compensation can further enhance system reliability. For more information regarding LCD display module issues, feel free to consult us!