IIC I2C TWI SPI Serial Interface Board Port 1602 2004 LCD LCD1602 Adapter Plate LCD Adapter Converter Module PCF8574

Features:
Supply voltage: 5V
Saves using up data ports on the Arduino
The backlight and contrast is adjusted by potentiometer/trimmer
Come with 2 IIC interface, which can be connected by Dupont Line or IIC dedicated cable
Compatible for 1602 LCD 2004 LCD.This module can drive 2 and 4 line LCD displays for Arduino
With this I2C interface module, you will be able to realize data display via only 2 wires.
I2C Address: 0X20~0X27 (the original address is 0X20,you can change it yourself)
Description:
As there is limited pin on Arduino controller,your project may be not able to use normal LCD shield after connected with a certain quantity of sensors or SD card. However, with this I2C LCD serial interface module, you will be able to realize data display via only 2 wires.
The I2C expander is address-selectable (8 values),and it provides 7 I/O ports and one switch-control port (backlight for LCDs). It attaches directly to the usual 2x and 4x LCD displays with a single controller (e.g., 4x20).
The brain is a PCF8574T 8-bit I2C GPIO expander wired up for 4-bit communication with the LCD.
This board is capable of reading and writing in 4-bit mode, and it also can toggle the backlight.
The register layout is:
D7, D6, D5, D4, BACKLIGHT (wired to V0), E (clock/enable), R/W (direction), RS (command/data mode)
For writing to the LCD, data is read out of the interface on the falling edge of the ENABLE bit. This means that you have to send each frame twice, once with ENABLE high, and then once again with ENABLE low.