When selecting LCD display modules, the main focus is on the following indicators:

LCD screen (resolution, dot pitch, duty cycle; positive and negative display; color; FSTN, STN).

Drive mode (drive IC, with or without control IC).

Drive voltage (built-in, external; positive, negative, voltage value).

Backlight forms (CCFL, LED, EL; side back, bottom back).

Module structure (TAB, COG, COB; installation structure).

Interface methods (parallel port 80, parallel port 68, serial port 232, serial port I2C).

Selection steps:

1. When selecting a LCD module, the first consideration is the display content, and the dot matrix is determined based on the display content.

2. Determine the size of the liquid crystal based on its structure, including its shape and effective display area.

3. Operating environment: temperature, light, humidity, mechanical strength, etc., must also be considered. Detailed instructions:

Temperature types: room temperature type (0~+50 degrees), wide temperature type (-20~+70 degrees).

According to the applicable ambient lighting conditions:

a) Reflective type (without backlight, illuminated or used during the day), suitable for outdoor environments with strong light.

b) Transparent and reflective (with backlight, in light or darkness), can turn on or off backlight according to light, suitable for outdoor use.

c) Transmission type (with backlight, in light or darkness), backlight must be turned on and not suitable for outdoor use.

For high humidity and high mechanical vibration intensity: it is recommended to use TAB or COG products, which are more reliable in connection and less prone to mold corrosion.

COB has weak seismic resistance due to its connection with conductive adhesive strips, and the gold finger part of the PCB is prone to mold corrosion.

4. Based on CPU resources, select the interface method and determine if the LCD module has a built-in controller.

Nowadays, many ARM chips have LCD controllers inside, and cost can be considered comprehensively to choose the appropriate LCD module. Usually, LCD modules with 128 rows or less do not require a dedicated LCD controller. This type of LCD driver IC integrates the driver and control together. Lines 128 to 240 usually use a combination of driving IC and controlling IC.