lcd screen programming in stock

In this tutorial, I’ll explain how to set up an LCD on an Arduino and show you all the different ways you can program it. I’ll show you how to print text, scroll text, make custom characters, blink text, and position text. They’re great for any project that outputs data, and they can make your project a lot more interesting and interactive.

The display I’m using is a 16×2 LCD display that I bought for about $5. You may be wondering why it’s called a 16×2 LCD. The part 16×2 means that the LCD has 2 lines, and can display 16 characters per line. Therefore, a 16×2 LCD screen can display up to 32 characters at once. It is possible to display more than 32 characters with scrolling though.

The code in this article is written for LCD’s that use the standard Hitachi HD44780 driver. If your LCD has 16 pins, then it probably has the Hitachi HD44780 driver. These displays can be wired in either 4 bit mode or 8 bit mode. Wiring the LCD in 4 bit mode is usually preferred since it uses four less wires than 8 bit mode. In practice, there isn’t a noticeable difference in performance between the two modes. In this tutorial, I’ll connect the LCD in 4 bit mode.

Here’s a diagram of the pins on the LCD I’m using. The connections from each pin to the Arduino will be the same, but your pins might be arranged differently on the LCD. Be sure to check the datasheet or look for labels on your particular LCD:

Also, you might need to solder a 16 pin header to your LCD before connecting it to a breadboard. Follow the diagram below to wire the LCD to your Arduino:

Now we’re ready to get into the programming! I’ll go over more interesting things you can do in a moment, but for now lets just run a simple test program. This program will print “hello, world!” to the screen. Enter this code into the Arduino IDE and upload it to the board:

There are 19 different functions in the LiquidCrystal library available for us to use. These functions do things like change the position of the text, move text across the screen, or make the display turn on or off. What follows is a short description of each function, and how to use it in a program.

TheLiquidCrystal() function sets the pins the Arduino uses to connect to the LCD. You can use any of the Arduino’s digital pins to control the LCD. Just put the Arduino pin numbers inside the parentheses in this order:

This function sets the dimensions of the LCD. It needs to be placed before any other LiquidCrystal function in the void setup() section of the program. The number of rows and columns are specified as lcd.begin(columns, rows). For a 16×2 LCD, you would use lcd.begin(16, 2), and for a 20×4 LCD you would use lcd.begin(20, 4).

This function clears any text or data already displayed on the LCD. If you use lcd.clear() with lcd.print() and the delay() function in the void loop() section, you can make a simple blinking text program:

This function places the cursor in the upper left hand corner of the screen, and prints any subsequent text from that position. For example, this code replaces the first three letters of “hello world!” with X’s:

Similar, but more useful than lcd.home() is lcd.setCursor(). This function places the cursor (and any printed text) at any position on the screen. It can be used in the void setup() or void loop() section of your program.

The cursor position is defined with lcd.setCursor(column, row). The column and row coordinates start from zero (0-15 and 0-1 respectively). For example, using lcd.setCursor(2, 1) in the void setup() section of the “hello, world!” program above prints “hello, world!” to the lower line and shifts it to the right two spaces:

You can use this function to write different types of data to the LCD, for example the reading from a temperature sensor, or the coordinates from a GPS module. You can also use it to print custom characters that you create yourself (more on this below). Use lcd.write() in the void setup() or void loop() section of your program.

The function lcd.noCursor() turns the cursor off. lcd.cursor() and lcd.noCursor() can be used together in the void loop() section to make a blinking cursor similar to what you see in many text input fields:

Cursors can be placed anywhere on the screen with the lcd.setCursor() function. This code places a blinking cursor directly below the exclamation point in “hello, world!”:

This function creates a block style cursor that blinks on and off at approximately 500 milliseconds per cycle. Use it in the void loop() section. The function lcd.noBlink() disables the blinking block cursor.

This function turns on any text or cursors that have been printed to the LCD screen. The function lcd.noDisplay() turns off any text or cursors printed to the LCD, without clearing it from the LCD’s memory.

This function takes anything printed to the LCD and moves it to the left. It should be used in the void loop() section with a delay command following it. The function will move the text 40 spaces to the left before it loops back to the first character. This code moves the “hello, world!” text to the left, at a rate of one second per character:

Like the lcd.scrollDisplay() functions, the text can be up to 40 characters in length before repeating. At first glance, this function seems less useful than the lcd.scrollDisplay() functions, but it can be very useful for creating animations with custom characters.

lcd.noAutoscroll() turns the lcd.autoscroll() function off. Use this function before or after lcd.autoscroll() in the void loop() section to create sequences of scrolling text or animations.

This function sets the direction that text is printed to the screen. The default mode is from left to right using the command lcd.leftToRight(), but you may find some cases where it’s useful to output text in the reverse direction:

This code prints the “hello, world!” text as “!dlrow ,olleh”. Unless you specify the placement of the cursor with lcd.setCursor(), the text will print from the (0, 1) position and only the first character of the string will be visible.

This command allows you to create your own custom characters. Each character of a 16×2 LCD has a 5 pixel width and an 8 pixel height. Up to 8 different custom characters can be defined in a single program. To design your own characters, you’ll need to make a binary matrix of your custom character from an LCD character generator or map it yourself. This code creates a degree symbol (°):

An LCD (liquid crystal display) is a thin and flat screen made up of several coloured or black and white pixels located in front of a light source or reflector. It is often used in battery-powered electronic devices, which use very small quantities of electrical energy. It allows information to be given to the user on what is happening in the program, which is very useful and can make projects even more interactive. In this lesson we will be using an I2C/SPI LCD module. With this module, only 2 signals are required to display information when controlled by I2C, or 3 if controlled by SPI. This LCD in particular has 20 columns x 4 rows, allowing 80 characters to be written on the screen (with the library that we will be using, only ASCII characters can be used).

To program the LCD module, we will need to use a library. What is a library? Simply a series of functions that someone has written for us to make our work easier. This means that, instead of having the values in the pins, we will have high-level functions such as lcd.print(“hola”) that do the dirty work for us. The library used to control the LCD is called liquidCrystal. However, if the Arduino library is designed for LCDs, they will need 6 signals in order to be controlled. Thanks to the IIC/SPI module, the LCD in this lesson only needs 4, which is why BQ has modified the library so that it functions correctly.

Now we have the necessary library and everything is connected. We will start off with Hello World! (¡Hola Mundo!), displaying the textArduino Course on the screen. Here you have the code:

The LiquidCrystal variable type will enable us to control the LCD module. So we will start off with a global variable of this type, which we have called lcd in this case. We will also start off with value 0. From now on, all operations on the LCD will be lcd.xxxtype.

How about if we wanted “BQ” to appear moving across the screen? I will leave you the code here so that you can try it out yourself, analyse it and if you want, you can change it to make it display something else.

So you want to set up your LCD module with your Arduino – but jeeze!  What to do with all those pins?  Which ones go where?  Are there anything things to look out for when buying or setting up a new LCD Module?

Notice some verbiage as we talk about LCDs, you will keep seeing the two words “LCD Module”.  This is because, when you buy LCD screens – you are more than likely going to buy it as a “plug-and-play” module.

The LCD screen itself is a subcomponent of the module, which includes other components and circuitry that make interfacing with the LCD screen far more accessible.

Let’s cut to the chase – the MOST important thing you need to ensure when you are buying your LCD is that is compatible with Hitachi HD44780 driver.  Let me say that bigger:

But don’t worry.  This driver is so common it is pretty much the standard.  If you can’t find any documentation to support whether or not the LCD you want to buy will work, then check the pin out.  Does it have 16 pins?  If the answer is yes, you should feel pretty comfortable that it is compatible.

So why do we need an LCD that is compatible with the Hitachi HD44780 driver?  It’s because the LiquidCrystal Library that we will be using to control the LCD from the Arduino uses the driver as its standard.  The functions in the library won’t necessarily work on other types of LCD screens.

LCDs can also come in different colors – so you don’t have to go for the standard martian green.  Plus, they can have backlights to help make the characters to stand out better in different light settings.

The LCD you buy will have 16 pads where you will hook up wires or headers to connect to your Arduino, but many manufactures have made modules that also have a second set of 16 pins that are simply duplicates of the first.

The one I use in this video tutorial series has a set of 16 pads at the top of the LCD and 16 pads at the bottom.  What this provides for is more flexibility in where you can connect your wires to control the LCD.

For example, if you plan on mounting your LCD panel in some type of enclosure, maybe the bottom pins would be more accessible.  You can also use some pads on the top and some on the bottom – since they connect to the same thing on the LCD module the top and bottom pins are interchangeable.

You may also consider soldering on pin headers to the module.  These make connecting your LCD to a breadboard for prototyping about a million times easier. You may not be able to find a 16 pin header, but they are made to be clipped to your desired length.

The final thing I would mention is to check the pin numbering on the PCB.  The LCD module I bought only had the numbers 1 and 16 on the far sides of each of the pads.  This made it a little confusing when trying to figure out which wire to hook where.

LCD screens are useful and found in many parts of our life. At the train station, parking meter, vending machines communicating brief messages on how we interact with the machine they are connected to. LCD screens are a fun way to communicate information in Raspberry Pi Pico projects and other Raspberry Pi Projects. They have a big bright screen which can display text, numbers and characters across a 16 x 2 screen. The 16 refers to 16 characters across the screen, and the 2 represents the number of rows we have. We can get LCD screens with 20x2, 20x4 and many other configurations, but 16x2 is the most common.

In this tutorial, we will learn how to connect an LCD screen, an HD44780, to a Raspberry Pi Pico via the I2C interface using the attached I2C backpack, then we will install a MicroPython library via the Thonny editor and learn how to use it to write text to the display, control the cursor and the backlight.

2. Import four librariesof pre-written code. The first two are from the Machine library and they enable us to use I2C and GPIO pins. Next we import the sleep function from Time enabling us to pause the code. Finally we import the I2C library to interact with the LCD screen.from machine import I2C, Pin

3. Create an objecti2c to communicate with the LCD screen over the I2C protocol. Here we are using I2C channel 0, which maps SDA to GP0 and SCL to GP1.i2c = I2C(0, sda=Pin(0), scl=Pin(1), freq=400000)

5. Create an objectlcdto set up the I2C connection for the library. It tells the library what I2C pins we are using, set via the i2c object, the address of our screen, set via I2C_ADDRand finally it sets that we have a screen with two rows and 16 columns.lcd = I2cLcd(i2c, I2C_ADDR, 2, 16)

8. Write two lines of textto the screen. The first will print “I2C Address:” followed by the address stored inside the I2C_ADDR object. Then insert a new line character “\n” and then write another line saying “Tom’s Hardware" (or whatever you want it to say). Pause for two seconds to allow time to read the text.lcd.putstr("I2C Address:"+str(I2C_ADDR)+"\n")

9. Clear the screenbefore repeating the previous section of code, but this time we display the I2C address of the LCD display using its hex value. The PCF8574T chip used in the I2C backpack has two address, 0x20 and 0x27 and it is useful to know which it is using, especially if we are using multiple I2C devices as they may cause a clash on the bus.lcd.clear()

11. To flash the LED backlight, use a for loopthat will iterate ten times. It will turn on the backlight for 0.2 seconds, then turn it off for the same time. The “Backlight Test” text will remain on the screen even with the backlight off.for i in range(10):

12. Turn the backlight back onand then hide the cursor. Sometimes, a flashing cursor can detract from the information we are trying to communicate.lcd.backlight_on()

13. Create a for loopthat will print the number 0 to 19 on the LCD screen. Note that there is a 0.4 second delay before we delete the value and replace it with the next. We have to delete the text as overwriting the text will make it look garbled.for i in range(20):

Save and runyour code. As with any Python script in Thonny, Click on File >> Saveand save the file to your Raspberry Pi Pico. We recommend calling it i2c_lcd_test.py. When ready, click on the Green play buttonto start the code and watch as the test runs on the screen.

As a 2inch IPS display module with a resolution of 240 * 320, it uses an SPI interface for communication. The LCD has an internal controller with basic functions, which can be used to draw points, lines, circles, and rectangles, and display English, Chinese as well as pictures.

The 2inch LCD uses the PH2.0 8PIN interface, which can be connected to the Raspberry Pi according to the above table: (Please connect according to the pin definition table. The color of the wiring in the picture is for reference only, and the actual color shall prevail.)

The LCD supports 12-bit, 16-bit, and 18-bit input color formats per pixel, namely RGB444, RGB565, and RGB666 three color formats, this demo uses RGB565 color format, which is also a commonly used RGB format.

For most LCD controllers, the communication mode of the controller can be configured, usually with an 8080 parallel interface, three-wire SPI, four-wire SPI, and other communication methods. This LCD uses a four-wire SPI communication interface, which can greatly save the GPIO port, and the communication speed will be faster.

The fill color of a certain window in the image buffer: the image buffer part of the window filled with a certain color, usually used to fresh the screen into blank, often used for time display, fresh the last second of the screen.

2. The module_init() function is automatically called in the INIT () initializer on the LCD, but the module_exit() function needs to be called by itself

Python has an image library PIL official library link, it do not need to write code from the logical layer like C, can directly call to the image library for image processing. The following will take 1.54inch LCD as an example, we provide a brief description for the demo.

Micor:bit has variety of programming methods like mbed, micropython, typescript and other programming methods, as well as code online websites which are abundant.

Place the block before send display data. You can choose the position, color and size. For the screen, (1,1) is on top-left, and (160,128) is on bottom-right

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