iic i2c 1602 lcd module blue screen library files made in china

3 pin: V0 is LCD contrast adjustment side,it is the the weakest contrast when connect positive-supply, it is the highest contrast contrast when connect grounding power

Connecting an LCD to your Raspberry Pi will spice up almost any project, but what if your pins are tied up with connections to other modules? No problem, just connect your LCD with I2C, it only uses two pins (well, four if you count the ground and power).

In this tutorial, I’ll show you everything you need to set up an LCD using I2C, but if you want to learn more about I2C and the details of how it works, check out our article Basics of the I2C Communication Protocol.

There are a couple ways to use I2C to connect an LCD to the Raspberry Pi. The simplest is to get an LCD with an I2C backpack. But the hardcore DIY way is to use a standard HD44780 LCD and connect it to the Pi via a chip called the PCF8574.

The PCF8574 converts the I2C signal sent from the Pi into a parallel signal that can be used by the LCD. Most I2C LCDs use the PCF8574 anyway. I’ll explain how to connect it both ways in a minute.

I’ll also show you how to program the LCD using Python, and provide examples for how to print and position the text, clear the screen, scroll text, print data from a sensor, print the date and time, and print the IP address of your Pi.

I2C (inter-integrated circuit) is also known as the two-wire interface since it only uses two wires to send and receive data. Actually it takes four if you count the Vcc and ground wires, but the power could always come from another source.

Connecting an LCD with an I2C backpack is pretty self-explanatory. Connect the SDA pin on the Pi to the SDA pin on the LCD, and the SCL pin on the Pi to the SCL pin on the LCD. The ground and Vcc pins will also need to be connected. Most LCDs can operate with 3.3V, but they’re meant to be run on 5V, so connect it to the 5V pin of the Pi if possible.

If you have an LCD without I2C and have a PCF8574 chip lying around, you can use it to connect your LCD with a little extra wiring. The PCF8574 is an 8 bit I/O expander which converts a parallel signal into I2C and vice-versa. The Raspberry Pi sends data to the PCF8574 via I2C. The PCF8574 then converts the I2C signal into a 4 bit parallel signal, which is relayed to the LCD.

Before we get into the programming, we need to make sure the I2C module is enabled on the Pi and install a couple tools that will make it easier to use I2C.

Now we need to install a program called I2C-tools, which will tell us the I2C address of the LCD when it’s connected to the Pi. So at the command prompt, enter sudo apt-get install i2c-tools.

Next we need to install SMBUS, which gives the Python library we’re going to use access to the I2C bus on the Pi. At the command prompt, enter sudo apt-get install python-smbus.

Now reboot the Pi and log in again. With your LCD connected, enter i2cdetect -y 1 at the command prompt. This will show you a table of addresses for each I2C device connected to your Pi:

We’ll be using Python to program the LCD, so if this is your first time writing/running a Python program, you may want to check out How to Write and Run a Python Program on the Raspberry Pi before proceeding.

I found a Python I2C library that has a good set of functions and works pretty well. This library was originally posted here, then expanded and improved by GitHub user DenisFromHR.

There are a couple things you may need to change in the code above, depending on your set up. On line 19 there is a function that defines the port for the I2C bus (I2CBUS = 0). Older Raspberry Pi’s used port 0, but newer models use port 1. So depending on which RPi model you have, you might need to change this from 0 to 1.

The function mylcd.lcd_display_string() prints text to the screen and also lets you chose where to position it. The function is used as mylcd.lcd_display_string("TEXT TO PRINT", ROW, COLUMN). For example, the following code prints “Hello World!” to row 2, column 3:

On a 16×2 LCD, the rows are numbered 1 – 2, while the columns are numbered 0 – 15. So to print “Hello World!” at the first column of the top row, you would use mylcd.lcd_display_string("Hello World!", 1, 0).

You can create any pattern you want and print it to the display as a custom character. Each character is an array of 5 x 8 pixels. Up to 8 custom characters can be defined and stored in the LCD’s memory. This custom character generator will help you create the bit array needed to define the characters in the LCD memory.

By inserting the variable from your sensor into the mylcd.lcd_display_string() function (line 22 in the code above) you can print the sensor data just like any other text string.

These programs are just basic examples of ways you can control text on your LCD. Try changing things around and combining the code to get some interesting effects. For example, you can make some fun animations by scrolling with custom characters. Don’t have enough screen space to output all of your sensor data? Just print and clear each reading for a couple seconds in a loop.

Many drawing and writing primitives are provided: single pixel plotting, lines, circles, triangles, rectangles (with square and rounded corners), and corresponding filled shapes. Text and numeric values, may be placed anywhere on the screen in a variety of sizes. Bitmapped shapes can be scrolled or moved about the screen and the whole screen can be rotated.

Points are defined by their Cartesian co-ordinates, (x, y). The origin (0, 0) is at the top left of the screen. Increasing the y value moves down the screen. The addressable dimensions of the SSD1306 screen are 128 pixels left to right (0, 1, 2, …, 127) and 64 pixels from top to bottom (0, 1, 2, …, 63). The pixel in the bottom right corner is (127, 63).

These are based on the system used for printing to the Serial monitor with print() and println(). The font included with the library is 5 pixels wide and 7 pixels tall but prints into a 6x8 pixel space.

None of these instructions will produce a change on the screen without a display.display(); method. If your script does not appear to be working check you have included this line at the bottom of your screen changing code.

Like many on this discussion group, I bought an I2C LCD device for my Arduino only to find that the documentation is either non-existent or, if it does exist, just wrong.

Firstly, the LCD panel I have is an I2C from sainsmart. It’s a 16x2 LCD based on the 1602 panel with a small back-panel to convert it to I2C. It’s shown here http://farm9.staticflickr.com/8046/8115486011_a99d721319_b.jpg for clarity.

Reviewing the photo at http://farm9.staticflickr.com/8046/8115486011_a99d721319_b.jpg you can see the four wires attached to the top of the device. The connections, from left to right, are GND, VCC, SDA and SCL. These latter two are the I2C leads.

My Arduino is an Uno, so the I2C connections are on SDA=A4 and SCL=A5. So go ahead and wire these up, along with the two power leads to the 5V and GND terminals.

You should see the LCD light up. Depending on how the device was constructed, you might want to turn down the contrast of the LCD; you can do this by inserting a screwdriver into the potentiometer at the back. I suggest you turn it half-way so that there’s still a little contrast.

Each device has an I2C address that it uses to accept commands or send messages. Unfortunately this is one of the areas where the documentation falls down. So let’s go and look for the one on your device.

Load the sketch over at Arduino Playground - I2cScanner and follow the instructions to use it. By opening up the monitor window after you upload the sketch, Arduino will scan the address range looking for a reply. Even though the documentation said it was 0x27, this scanner detected it at 0x3F… so I was never going to find it based on the documentation!

The principle of the LCD1602 liquid crystal display is to use the physical characteristics of the liquid crystal to control the display area by voltage,

NOTE: After continuous iteration, the new product has updated the address of the register. At present, the address of the latest product is 0x3F, and the original old version is 0x2F. For the difference method, please check that the silk screen of the adapter board on the back contains MH as the new version, and the distance between the sliding rheostat The bottom pad space is larger.

Before we get into the programming, we need to make sure the I2C module is enabled on the Pi and install a couple tools that will make it easier to use I2C.

By inserting the variable from your sensor into the mylcd.lcd_display_string() function (line 22 in the code above) you can print the sensor data just like any other text string.

Today I am going to interface LCD to STM32 using an I2C device (PCF8574). PCF8574can be used as a port extender, to which LCD will be connected. If you haven’t read my previous post about I2C go check that out HERE.

Well you generally don’t but as I mentioned in my previous article that we can connect up to 128 devices on the same I2C line and let’s say we want to connect two different LCDs on the same I2C line, than we can’t use two PCF8574 with same addresses and we need to modify one of them.

As shown in the figure above, first pin of the device is Vsswhich is pin 1 of LCD. So all you have to do is connect first pins of the LCD to Vssabove and rest will connect accordingly. Starting with Vss as first pin, connection is as follows:-

As according to the datasheet of the LCD 16×2, in order to initialize the LCD, we have to use some sequence of commands. The code is commented properly, so that you can understand it better

An LCD display that can display a max of 16x2 charactors. with the help of the I2C bus convertor and related libraries, you can easily use this module with just 2 wires.

You can also make the LCD to display your own chars or logos as you like, you need to constrat your own chars in your program, as the method in the "CustomChars" demo. also, it would be easy for you to make the LCD display what you input with the serial port, just as the "SerialDisplay" demo, you can sent what you want to display with the serial monitor in the Arduino IDE, please note that you should set the baudrate to 9600. for me, i want the I2C LCD 1602 to show "good day".