How to Choose an TFT LCD Module?

TFT LCD Module manufacturers design many standard module products according to market demand to meet the needs of a wide range of customers. This article offers some suggestions for selecting a suitable LCD display module based on the needs of developing products.

When choosing a suitable TFT LCD Module, the following three key indicators must be considered:

1. Display resolution: The number of pixels in the LCD display module must be greater than the maximum number of pixels required for the product's display content.

2. Outer dimension: The size of the LCD display module must be suitable for the product's chassis structure size.

3. Circuit matching: The choice of the circuit for the LCD display module will directly affect the circuit design of the MPU system. The circuit comparison needs to consider the MPU system resources and module circuit characteristics comprehensively.

●Built-in driver LCD display module, configured with an MPU with a liquid crystal display driver, such as the ARM9 series.

●Built-in controller LCD display module and the controller has many models, each with its own characteristics, such as those with a Chinese character library, those with a two-dimensional graphics accelerator, and those with only a display RAM, which can meet the needs of various MPU systems.

●Interface form between module and MPU: parallel interface, divided into INTEL8080 and MC6800 timing; the serial interface, divided into 3-wire/4-wire SPI serial interface, RS-232 interface, and I2C bus interface.

●Adaptation of the logical power supply of the MPU system: the power supply voltage and signal level of the module is consistent, and the working power supply and signal voltage of the module is consistent with the power supply and signal level provided by the MPU system, reducing the level conversion circuit for signal connection.

●Circuit power consumption: it is necessary to evaluate whether the MPU system power supply can support the circuit's working state current, sleep state current, backlight current, etc.

The content priority method is to select standard products by prioritizing the requirements of the displayed image and balancing them with the structure. This method is used when the product's chassis structure leaves a large selection space for the module or when the chassis can refer to the size layout of the module. The specific steps are as follows.

Step 1: First, design the content of the image that the product needs to display, such as the content of the menu and the size of the graphics, to determine the display resolution of the module, which is the maximum dot matrix of the displayed pixels.

Step 2: Look for standard module product series according to the display resolution. These standard module product series all have the same or similar display resolution, but the module's structural size is slightly different.

Step 3: Compare the size of the selected standard module product series with the size of the chassis structure used in the development product and select one of the standard module product series.

Step 4: In the selected standard module series, select a standard module model according to the resources of the product's MPU system.

Step 5: Check whether the selected TFT LCD Module meets the requirements of the display and structure. If it meets the requirements, select it; otherwise, redo the process until it is appropriate.

This method maximizes the satisfaction of the display effect, as illustrated by the following example:

First, estimate the maximum size of graphics and the number of characters required by the menu in terms of the pixel dot matrix. There are 13 menu items, each with a maximum of 18 Chinese characters. Based on the national standard Chinese character 16x16 dot matrix font data, a line requires a minimum of 18x16=288 pixel columns; a minimum of 13x16=208 pixel rows. Thus, the minimum display resolution is 300x208 pixels.