LCD Module

Overview

LeMaker boards support a variety of display options beyond standard HDMI output, including dedicated LCD modules connected through LVDS and parallel RGB interfaces. This guide covers the hardware connection, software configuration, and troubleshooting for LCD modules used with the Banana Pi, Banana Pro, and other LeMaker single-board computers. The official LeMaker 7-inch LCD module is the primary focus, though the configuration principles apply to other compatible displays.

Display Interfaces

The Allwinner A20 SoC in the Banana Pi and Banana Pro supports multiple display output paths. HDMI is the most common and requires no additional configuration for standard monitors. The LVDS (Low-Voltage Differential Signalling) interface provides a high-speed, low-noise connection ideal for embedded LCD panels. Parallel RGB is a simpler interface used by some smaller displays. The display output is controlled by the display engine (DE) block in the SoC, which can drive two independent display channels simultaneously, allowing HDMI and LCD output at the same time.

LeMaker 7-Inch LCD Module

The official LeMaker 7-inch LCD module features a 1024×600 pixel IPS display with a resistive or capacitive touch panel. The module connects to the Banana Pi or Banana Pro via a 40-pin LVDS ribbon cable and a separate touch panel cable. The display panel operates at 3.3V logic levels and requires a 5V power supply delivered through the ribbon cable connector. The viewing angle is approximately 170 degrees horizontal and 170 degrees vertical, providing good visibility from multiple positions. The backlight brightness can be controlled via PWM when properly configured.

Hardware Connection

Power off the board completely before connecting the LCD module. Locate the LVDS connector on the board, which is the large flat ribbon cable connector near the GPIO header. Carefully insert the LVDS ribbon cable with the contacts facing downward, ensuring proper alignment of pin 1. Secure the locking mechanism on the connector. Connect the touch panel ribbon cable to the designated touch connector on the board. Double-check all connections before powering on. A loose LVDS cable is the most common cause of display issues including no output, distorted image, or intermittent flickering.

Fex and Device Tree Configuration

For older sunxi kernels using the fex configuration system, edit the board's fex file to enable the LCD output. Set [disp_init] parameters including disp_mode = 0 for single LCD output and configure the [lcd0_para] section with the correct timing parameters: lcd_x = 1024, lcd_y = 600, lcd_dclk_freq = 51, lcd_if = 3 for LVDS mode, and the appropriate horizontal and vertical blanking values. Convert the fex file to binary with fex2bin board.fex script.bin and place the resulting script.bin on the boot partition.

Resolution and Refresh Rate

The display timing parameters must match the LCD panel's native specifications. The pixel clock frequency, horizontal total (active pixels plus blanking), and vertical total (active lines plus blanking) together determine the refresh rate. For the 7-inch module at 1024×600, a pixel clock of 51 MHz with standard blanking yields approximately 60 Hz refresh rate. Incorrect timing parameters can result in no display output, a shifted image, or damage to the LCD panel in extreme cases. Always verify timing values against the panel's datasheet before applying configuration changes.

Touch Panel Calibration

After the display is working, calibrate the touch panel for accurate input. For resistive touch panels, use ts_calibrate from the tslib package by running sudo apt-get install libts-bin followed by sudo ts_calibrate. Follow the on-screen prompts to touch the calibration points. The calibration data is stored in /etc/pointercal. For capacitive touch panels using an I2C controller such as the Goodix GT911, the Linux kernel driver handles most configuration automatically, but you may need to verify the I2C device address and interrupt GPIO in the device tree or fex configuration.

Troubleshooting

If the display shows no output, verify the LVDS cable connection and ensure the LCD output is enabled in the fex or device tree configuration. Check that the correct display driver is loaded with dmesg | grep -i disp. If the image appears with wrong colours or colour banding, the LVDS channel mapping or colour depth settings may be incorrect. For touch panel issues, verify the touch controller is detected on the I2C bus with i2cdetect -y 1 and check that the input device appears under /dev/input/.

Related Pages

For board-specific LCD configuration, see the Banana Pro LCD Module documentation. For fex file editing details, refer to Banana Pi Fex Configuration.

Author: LeMaker Documentation Team
Last updated: 2026-02-10