lcm lcd module free sample

The parallel interface typically controls the LCD via 8 data pins and 3 control lines. The control lines used are Enable (E), Register Select (RS), and Read/Write (R/W). RS tells the LCD module if the information being sent is an Instruction or Data. The Enable tells the LCD module that the data or instruction in the register is ready to be interpreted by the LCD Module. Some controllers may have more than one Enable Control Line. The Read/Write tells the module whether to write data or read data from the register.

Serial LCD controllers typically have one Serial Data Line that writes data and cannot read. Normally, a Register Select Line(Sometimes designated A0) is used to tell the controller whether the incoming data is display information or a controller command

SPI, or Serial Peripheral Interface bus, is a synchronous (data is synchronized to the clock) serial data link standard that operates in full duplex mode, which means that devices that can communicate with one another simultaneously. To do this, two data lines are required. With this standard, devices communicate in a master/slave mode, where the master device (host processor) initiates the data and the clock. The LCD module is the (or one of the) peripheral slave device(s) attached to the data bus. Multiple peripherals (display modules and other devices) are addressed on the same serial data bus. However, the LCD module will only listen to the data it sees when the Chip Select line is active (usually low). If the Chip Select line is inactive (usually High), the LCD module listens to the data on the bus, but ignores it. The SDO line is not active when this state occurs. The SPI bus is comprised of four logic signals, two control lines and two data lines and is commonly referred to as SPI (4 wire).

With CS (Chip-Select) the corresponding peripheral device is selected by the LCD Controller. This pin is mostly active-low. In the unselected state the SDO lines are hi-impedance and therefore inactive. The clock line SCL is brought to the device whether it is selected or not. The clock serves as synchronization of the data communication.

The chip select signal CS is optional for a single device system, because you could tie the CS input at the LCD Module low, if the other lines are dedicated to SPI use. This is sometimes called a 3 Wire SPI Interface.

SPI Data transmissions usually involve two shift registers. Most display module applications normally use 8-bit words. However, different size words, such as 12 bit, are also used. By convention, the most significant bit is shifted out of one shift register while the least significant bit is shifted in. The word is then written into memory if the CS (chip-select) is low (active). If not, the data is ignored.

Lumex LCD module with Built-in SSD1306 I2C Interface, LCM-H12864GWN-WI2C, is the newest product belongs to Lumex Display Adapting Service. LCM-H12864GWN-WI2C is graphic type transflective LCD in 128*64 pixels with white backlight. With built-in SSD1306 I2C interface, LCM-H12864GWN-WI2C is able to direct replace most 128 x 64 pixels OLED in the market.

LCM-H12864GWN-WI2C also comes with UART interface like other ezDisplay product. Devices such as raspberry pi, arduino and other simimar system is able to use LCM-H12864GWN-WI2C simply with four wires(pins).