FAQs of Graphic LCD: Concept, Classification, Common Dot Matrix and Driver

FAQs of Graphic LCD: Concept, Classification, Common Dot Matrix and Driver

I. What is a Graphic LCD Display?

A graphic LCD （Liquid Crystal Display）consists of a matrix of pixels arranged in rows and columns. Each pixel is controlled by its driver circuit and can be individually turned on or off, allowing for the display of characters, text, and complex graphics.

This LCD consists of the liquid crystal display panel, the CMOS driver, and the CMOS controller.

●There are character generation memory and display data memory inside.

● Most of these LCDs have a direct interface with the microcontroller. All display functions are implemented by the controller with instructions.

● It is powered by +3.3V/+5V. The circuit inside the LCD provides the power reverse voltage required by the liquid crystal display.

● The most common resolutions are 128X64, 240X128, 320×240, and other models. The number before the X is the number of columns of the dot matrix, while the number after is the number of rows of the dot matrix.

II. How Many Types of Graphic LCDs? / How to Classify Graphic LCDs?

Graphic LCDs can be classified based on various factors. Here are some common classification categories for graphic LCDs:

Display Type

a. Monochrome Graphic LCD: These displays typically use a single color, such as black and white or grayscale, to represent the graphical and textual information.

b. Color Graphic LCD: These displays can produce full-color images by incorporating color filters or using RGB (Red, Green, Blue) subpixels.

Display Technology

a. Twisted Nematic (TN) LCD: This is the most common type of LCD technology used in graphic displays. TN LCDs provide good contrast and response time, but limited viewing angles.

b. Super Twisted Nematic (STN) LCD: STN LCDs offer improved viewing angles and wider temperature ranges than TN LCDs. They are commonly used in outdoor applications.

c. Film-compensated Super Twisted Nematic (FSTN) LCD: FSTN LCDs enhance contrast and readability under different lighting conditions. They are suitable for high-contrast applications.

d. In-Plane Switching (IPS) LCD: IPS LCDs offer superior color reproduction, wide viewing angles, and high-quality images. They are commonly used in color graphic displays.

Resolution

Graphic LCDs come in various resolutions.

Common resolutions include 128×64, 192×64, 240×128, 320×240, etc. Higher resolutions provide more detailed and sharper images.

Interface

Graphic LCDs can have different interface options for communication with external devices, such as microcontrollers or other digital systems.

Common interface types include parallel interfaces (e.g., 8-bit or 4-bit), Serial Peripheral Interface (SPI), Inter-Integrated Circuit (I2C), Universal Asynchronous Receiver-Transmitter (UART), etc.

Module Size

Graphic LCD displays are available in different physical sizes, ranging from small displays used in handheld devices to larger panels used in industrial applications. The module size is typically specified in inches or millimeters, such as 1.9″, 2.4”, 2.7″, 3.5″, 4.8″, 5.7″, etc.

III. What is the Common Dot Matrix and its Driver IC of Graphic LCDs?

(1) Dot matrix 128×64

LCD12864 has fonts and some without fonts; 5V voltage, and 3.3V~5V (built-in boost circuit); after all, the difference lies in the drive controller:

ST7920/ST7921

support serial or parallel data operation mode, built-in Chinese character library which saves the user from the trouble of compiling the font library.

The LCD of this controller also supports the drawing method. This type of LCD supports 68 timing 8-bit and 4-bit parallel ports and serial ports.

ST7567

is a controller specifically designed for the graphic monochrome LCD display.

It offers built-in features for displaying graphics and text, and uses a 4-wire SPI (Serial Peripheral Interface) communication interface to connect with the microcontroller.

KS0108

has simple instructions and no font library and supports the 68-timing 8-bit parallel port.

T6963C

is powerful and has a Western character library. There are text and graphics layers, and it supports a superimposed display of the two layers. Support 80 timing 8-bit parallel port.

Common controllers for COG: S6B0724 and ST7565

and the instructions of them are compatible. Support 68 timing 8-bit parallel port, 80 timing 8-bit parallel port, and serial port. The COG LCD is populated by light structure and low cost.

(2) Dot matrix 320×240

general use of RA8835 driver control IC.

Other dot matrix: 192×64, 240×64, 240×128, 320×64

generally use controller RA6963, T6963c, ST7920.

Therefore, remember to consult the datasheet or documentation of your LCD module to determine the controller chip used. This information will help you choose the appropriate library and understand the necessary wiring and initialization procedures.

V. Take Away

Compared with the current mainstream display technology TFT LCD, the advantages of using a graphic LCD include low power consumption, low cost, and easy integration with microcontrollers and single-board microcontrollers, like Arduino.

Even the display quality and image looks “outdated”, however, in industrial application, “Just is the Best.”.

Graphic LCD modules are usually used in applications with simple display requirements such as embedded systems, industrial control, and instruments that require simple interfaces only, reducing unnecessary redundancy and avoiding fancy distractions, such as industrial control panels, medical devices, automotive dashboards, and consumer DIY electronics. Click Graphic LCD products to learn about our offers or send us an email with your specific requirements.