So, it will have 16×2 = 32 characters in total and each character will be made of 5×8 Pixel Dots. There are a lot of combinations available like 8×1, 8×2, 10×2, 16×1, etc. 16×2 LCD is named so because it has 16 Columns and 2 Rows. In short, your backpack is based on PCF8574T and the address connections (A0-A1- A2) are not bridged with solder it will have the slave address 0x27. If your module holds a PCF8574AT chip, then the default slave address will change to 0x3F. This I2C module are cantered around PCF8574T (SO16 package of PCF8574 in DIP16 package) with a default slave address of 0x27. The PCF8574 is a silicon CMOS circuit provides general purpose remote I/O expansion (an 8-bit quasi-bidirectional) for most microcontroller families. this is a general purpose bidirectional 8 bit I/O port expander that uses the I2C protocol. Using the LCD backpack module, desired data can be displayed on the LCD through the I2C bus. Hitachi’s HD44780 based 16×2-character LCD are very cheap and widely available. The plate pot is for display contrast adjustment, and the jumper on the opposite side allows the back light is controlled by the program or remain off for power saving. In the module left side, we have 4 pins, and two are for power ( Vcc and GND ), and the other two are the interface I2C ( SDA and SCL ). As we are going to interface LCD display with I2C Module let us know in brief about it. Please refer this post as it is very much required to understand basic GPIO pin structure while programming Raspberry PI and Interfacing any external device with Raspberry.
In my Previous tutorial about Raspberry Pi GPIO we have seen basic details about GPIO pin structure and there use. In this project in continuation with understanding basic for interfacing external devices with Raspberry Pi we will interface 16×2 LCD Display using I2C Module.
In previous tutorial we have seen how to interface 16X2 LCD Displaywith Raspberry PI in 4bit mode using library from Adafruit.