LCD and CTP Interface Introduction-eDP Interface

There are several ways of connecting MCU (Microcontroller Unit) or MPU (Microprocesser Unit) or CPU (Central Processing Unit) with LCD, eDP interface is one of them.

Fig. 1 Connection Between MCU to LCD

Basic knowledge introduction (1):LCD Driving Waveform

LCD can’t be driven with DC (Direct Current), it has to be driven with AC (Alternative Current) and the overall current has to be ZERO. Otherwise, the Liquid Crystal Material will be damaged sooner or later.

Fig. 2 LCD Driving Waveform

Basic knowledge introduction (2):LCD Controller vs Driver

There are two types of Driver IC’s, Common Drivers and Segment Drivers. Common Drivers output signals to create the rows or numbers of lines. The Segment Drivers output the necessary signals to create the characters or columns.

The Controller IC receives data written in ASCII or JIS code from the MPU and stores this data in RAM. This data is then converted into serial character patterns and transferred to the LCD driver IC.

Drive/Controller IC is probably the most commonly found in a graphics module. This IC receives data from the MPU and stores it in RAM. Also, it accepts commands directly from the MPU for both the common and segment drivers.

eDP interface

DisplayPort (DP) is a digital display interface developed by a consortium of PC and chip manufacturers and standardized by the Video Electronics Standards Association (VESA). The interface is primarily used to connect a video source to a display device such as a computer monitor, and it can also carry audio, USB, and other forms of data.

DisplayPort was designed to replace VGA, DVI, and FPD-Link. The interface is backward compatible with other interfaces, such as HI and DVI, through the use of either active or passive adapters. It is mostly used for larger size and higher resolution displays.

Fig. 3 eDP Interface

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