20x4 lcd display with i2c interface quotation
ERM2004FS-3 is small size 20 characters wide,4 rows character lcd module,SPLC780C controller (Industry-standard HD44780 compatible controller),6800 4/8-bit parallel interface,single led backlight with white color included can be dimmed easily with a resistor or PWM,fstn-lcd positive,black text on the white color,high contrast,wide operating temperature range,wide view angle,rohs compliant,built in character set supports English/Japanese text, see the SPLC780C datasheet for the full character set, It"s optional for pin header connection,5V or 3.3V power supply and I2C adapter board for arduino.
Of course, we wouldn"t just leave you with a datasheet and a "good luck!".For 8051 microcontroller user,we prepared the detailed tutorial such as interfacing, demo code and Development Kit at the bottom of this page.
On previous tutorials on our website, we have covered the use of several displays, LCDs, and TFTs, with diverse Arduino boards. From Nokia 5110 LCD display to different types of OLEDs, the reason for the tutorials has been to ensure that, as a reader, you know how to use many of the most popular displays so this help you make the best choice when trying to select the perfect display for your project. For today’s tutorial, we will continue in that line and examine how to use the 20×4 I2C Character LCD Display with Arduino.
The 20×4 LCD display is essentially a bigger (increased number of rows and columns) version of the 16×2 LCD display with which we have built several projects. The display has room to display 20 columns of characters on 4 rows which makes it perfect for displaying a large amount of text without scrolling. Each of the columns has a resolution of 5×8 pixels which ensures its visibility from a substantial distance. Asides its size, the interesting thing about this version of the display being used for today’s tutorial is the fact that it communicates via I2C, which means we will only require 2 wires asides GND and VCC to connect the display to the Arduino. This is possible via the Parallel to I2C module coupled to the display as shown in picture below. The I2C module can also be bought individually, and coupled to the 16 pins version of the display.
To demonstrate how to use this display, we will build a real-time clock which will display date and time on the LCD. To generate and keep track of date and time, we will use the DS3231 Real time clock. We covered the use of the DS3231 RTC module in the tutorial on DS3231 based Real-time Clock, you can check it out to learn more about its use with the Arduino.
The exact component used for this tutorial can be bought via the links attached and the power bank is only required to run the Arduino when not connected to the computer. You can replace this with a 9V battery and a center-positive power jack.
Since the display and the real-time clock are both I2C devices, they will be connected to the same pins on the Arduino. For the Arduino Uno, the I2C pins are located on Pin A5 (SCL) and A4 (SDA). This may differ on any of the other Arduino boards. Connect the components as shown in the schematics below;
To write the code for this project, we will use three main libraries; the DS1307 Library to easily interface with the DS3231 module, the liquid crystal I2C library to easily interface with the LCD display, and the Wire library for I2C communication. While the Wire library comes built into the Arduino IDE, the other two libraries can be downloaded and installed via the links attached to them.
As mentioned during the introduction, our task for today is to obtain time and date information from the RTC module and display on the LCD. As usual, I will do a breakdown of the code and try to explain some of the concepts within it that may be difficult to understand.
We start the code by including the libraries that will be used. After which we create an object of the Liquid crystal library, with the I2C address of the LCD as an argument. The I2C address can be obtained from the seller or as described in our tutorial on using the 16×2 LCD display to ESP32.
Next, we create a set of variables which comprises of byte arrays that represent custom characters to be created and displayed. The custom characters are usually 5pixels in width and 8 pixels in height, representing each box in the rows or columns of the LCD. The byte array represents which pixels of the box to be turned on or off.
Next, we write the void setup function and start by initializing the library using the lcd.begin() function, with the first argument representing the number of columns, and the second argument representing the number of rows. After this, the CreateCustomCharacters() function is called to convert the char variables created above into characters that can be displayed on the LCD. One of the characters created is then used to create a UI/frame which is displayed using the printFrame() function.
The idea behind the voidloop function is simple. We create a variable “tm” to hold time elements and then call the RTC.read() function such that its response is stored in tm. This is all done within an if statement which prints the time and date value stored in tm, if a response is received from the rtc. If a response is not received, the else statement is executed.
The first function is the printTime() which breaks down the time data stored in the “tm” variable to extract seconds, minutes and hour values. These values are then displayed on the LCD using the lcd.print() function.
The printDate function is similar to the printTime function. It extracts date information from the variable tm and uses the lcd.print() function to display it.
The printFrame() function, on the other hand, was used to create a sort of user interface for the project. it makes use of the characters created above. Each of the custom characters created is displayed using the lcd.write(byte(x)) function with x being the character number of the character to be displayed. The characters are positioned on the LCD using the lcd.setCursor() function which takes numbers representing the column and row on which the character is to be displayed, as arguments.
Different projects, come with different screen requirements. If you need to display a large amount of information and the size is not a constraint, the 20×4 I2C display is definitely one of the options you should consider.
Sometimes it may be necessary to use a display while making a hardware project, but the size and the type of the display may vary according to the application. In a previous project, we used a 0.96″ I2C OLED display, and in this project we will have an I2C 20×4 character display.
This liquid crystal display has 4 lines, 20 character in each line and cannot be used to display graphics. The main feature of this display that it uses I2C interface, which means that you will need only two wires to connect with Arduino. At the back side of the screen there is a small PCB soldered in the display, this circuit is a serial LCD 20 x 4 module and it also has a small trimpot to adjust the contrast of the LCD.
Display’s backlight is blue and the text is white. It is fully compatible with Arduino and has 5V input voltage. Its I2C address could be 0x27 or 0x3F. You can get it for about $7 from Bangood store.
DS3231 is a low-cost, accurate I2C real-time clock (RTC), with an integrated temperature-compensated crystal oscillator (TCXO) and crystal. The device incorporates a battery input, so that if power is disconnected it maintains accurate time.
RTC maintains seconds, minutes, hours, day, date, month, and year information. Less than 31 days of the month, the end date will be automatically adjusted, including corrections for leap year. The clock operates in either the 24 hours or band / AM / PM indication of the 12-hour format. Provides two configurable alarm clock and a calendar can be set to a square wave output. Address and data are transferred serially through an I2C bidirectional bus.
This RTC module operates at input voltage range between 3.3V and 5.5V, so it can be connected with 3.3V or 5V pins. It is available on Banggood store for about $2.
First we need to download the library of the display, which includes all required functions to configure and write on the display. You can find it here.
Unzip the library and add it to the Arduino libraries folder, then run Arduino IDE and copy the following code. The first two lines are to include both of I2C and LCD libraries.
lcd.setCursor(3,0) will set the cursor of the LCD in the specified location, the first argument for the column and the second for the row starting form 0.
Here we will use a small breadboard to connect the RTC module and display with the Arduino’s I2C pins (A4 and A5). The SCL pins are connected with analog 5 pin and the SDA pins with analog 6 pin. The top rail of the breadboard used as I2C bus and the bottom one is power bus.
In addition to setup and loop function, we will create four other functions to organize the code. As the corners and vertical lines of the frame are special characters, we have to create them manually. So we will use a function to create them and another one to print them on the LCD.
Inside the loop function the time will be read from the real time clock module and the printed to the LCD using a custom function for each of time and date.
At first, we have to include the three libraries, I2C, LCD, and RTC and set the LCD address. Inside the setup function the display is initialized, then we will call createCustomCharacters() function and print them.
Each character can be 5-pixel long in width and 8-pixel in height. So to create a custom character we need to create a new byte. We need 5 characters, the vertical line and the four corners. The yellow pattern shows you how the character will be displayed on the LCD.
Inside createCustomCharacters() function, we called lcd.createChar(#, byte array) function. The LCD supports up to 8 custom characters numbered from 0 to 7. It will assign the index in the first argument to the character given by the byte array. To print this character we can use lcd.write(byte(#)) function.
This function is very simple, it uses lcd.setCursor(#,#) to move the cursor and lcd.print(“”) to print the given string. The function will print the top and bottom horizontal lines, then printing other custom characters.
As we discussed earlier, the loop function will get the current time and date every second and refresh them on the display. First we defined a time element “tm” which has current time data, then if the time is correct and the RTC module working fine the time and date will be printed.
PrintTime function uses three arguments, the column and line where it will print the time, and the time element. lcd.print(tm.Hour) will print the hour, then if the minutes and seconds are less than 10 we will add 0 to the left. And the same method is used to print the date.
If you want to add some visual output to your Arduino projects, you’ll need a display. If you need only little to display, the 20X4 LCD2004 Display with I2C Interface Module is a quite good solution.
This is 20x4 LCD Display that provides a simple and cost-effective solution that is very easy to interface with Arduino or Other Microcontrollers.. The display is 20 character by 4 line display has a very clear and high contrast white text upon a blue background/backlight. This is a great blue backlight LCD display. It is fantastic for Arduino based project.
This display overcomes the drawback of 20x4 LCD Display in which you’ll waste about 8 Pins on your Arduino for the display to get working. Luckily in this product, an I2C adapter is directly soldered right onto the pins of the display. So all you need to connect are the I2C pins, which shows a good library and little of coding.
The I2C is a type of serial bus which uses two bidirectional lines, called SDA (Serial Data Line) and SCL (Serial Clock Line). Both must be connected via pulled-up resistors. The usage voltages are standard as 5V and 3.3V.
These modules are currently supplied with a default I2C address of either 0x27 or 0x3F. To determine which version you have check the black I2C adaptor board on the underside of the module. If there a 3 sets of pads labelled A0, A1, & A2 then the default address will be 0x3F. If there are no pads the default address will be 0x27.
This article includes everything you need to know about using acharacter I2C LCD with Arduino. I have included a wiring diagram and many example codes to help you get started.
In the second half, I will go into more detail on how to display custom characters and how you can use the other functions of the LiquidCrystal_I2C library.
Once you know how to display text and numbers on the LCD, I suggest you take a look at the articles below. In these tutorials, you will learn how to measure and display sensor data on the LCD.
Each rectangle is made up of a grid of 5×8 pixels. Later in this tutorial, I will show you how you can control the individual pixels to display custom characters on the LCD.
They all use the same HD44780 Hitachi LCD controller, so you can easily swap them. You will only need to change the size specifications in your Arduino code.
The 16×2 and 20×4 datasheets include the dimensions of the LCD and you can find more information about the Hitachi LCD driver in the HD44780 datasheet.
Note that an Arduino Uno with the R3 layout (1.0 pinout) also has the SDA (data line) and SCL (clock line) pin headers close to the AREF pin. Check the table below for more details.
After you have wired up the LCD, you will need to adjust the contrast of the display. On the I2C module, you will find a potentiometer that you can turn with a small screwdriver.
The LiquidCrystal_I2C library works in combination with the Wire.h library which allows you to communicate with I2C devices. This library comes pre-installed with the Arduino IDE.
*When using the latest version of the LiquidCrystal_I2C library it is no longer needed to include the wire.h library in your sketch. The other library imports wire.h automatically.
Note that counting starts at 0 and the first argument specifies the column. So lcd.setCursor(2,1) sets the cursor on the third column and the second row.
Next the string ‘Hello World!’ is printed with lcd.print("Hello World!"). Note that you need to place quotation marks (” “) around the text since we are printing a text string.
The example sketch above shows you the basics of displaying text on the LCD. Now we will take a look at the other functions of the LiquidCrystal_I2C library.
This function turns on automatic scrolling of the LCD. This causes each character output to the display to push previous characters over by one space.
If the current text direction is left-to-right (the default), the display scrolls to the left, if the current direction is right-to-left, the display scrolls to the right.
I would love to know what projects you plan on building (or have already built) with these LCDs. If you have any questions, suggestions or if you think that things are missing in this tutorial, please leave a comment down below.
2012 latest IIC LCD2004-character LCD display module, a new high-quality 4 line 20 character LCD module not only set the contrast control knob selector switch also has a backlight and IIC communication interface. For Arduino beginners, not for the cumbersome and complex LCD driver circuit connection and a headache, the real significance of this LCD module will simplify the circuit, this module directly into the Arduino Sensor Shield V5.0 sensor expansion board IIC device interface can, GM 4P sensor connection cable, programmed through the Arduino controller, you can easily identify the slogan, sensor data records.
Everyone loves character LCD, is cheap and works out of box! This is 20x4 character LCD module. But the need for 6 to 10 GPIOs is the pain :) It takes most of GPIO of Arduino and other microcontroller. Now with this I2C or Two wires interface LCD, you will save a lot of GPIO for your sensor and motor control.
LCD shield after connected with a certain sensors or SD card. However, with this I2C interface LCD module, you will be able to realize data display via only 2 wires. If you already has I2C devices in your project, you can still program this LCD with the correct I2C address. It is fantastic for Arduino based project.
The PCF8574 style of I2C LCD adapter requires 5 bytes per LCD command / data operation. There is little point in sending a block of characters. I doubt if it is much faster than one chacter at a time.
The worst i2c LCD libraries are those from adafruit which send multiple bytes for every single signal on the LCD since they are treating the i/o expander port interface as a pseudo digitalWrite()/digitalRead() interface.
Transferring more bytes per i2c transaction can help as the over i2c overhead is reduced START and STOP times plus the i2c address byte for i2c increase the overhead and if they can be avoided, it can help.
Unfortunately, the print() interface in Arduino is single character to the lower layers, so it isn"t possible to use print() to send multiple characters to the lower library to try to speed transfers to the display.
This allows the things like CPU overhead and i2c transfer time to reduce any needed command execution delay all the way down to zero if those other overheads were longer than the LCD command execution.
This will cause the i2c h/w in the AVR to run just a tiny bit faster as rise time will be shorter and the chip will see bus signals just a tiny bit faster.
Just getting the i2c address may not be enough. This is because there is no standard for how the PCF8574 is wired up to the LCD or how to control the backlight. As a result different backpack manufacturers wire them up in different ways and use different backlight control circuits.
This means that even if the Arduino library is given the correct i2c address it still may not work if the library also does not know how the PCF8574 output port pins are wired up to the hd44780 LCD interface pins.
The sample code shown in the original post is using a LiquidCrystal_I2C library that assumes a particular pin wiring between the PCF8574 and the LCD. It appears to be using/expecting the LiquidCrystal_I2C library available through the IDE library manager.
If the backpack uses the specific wiring that the library assumes, then all that is necessary is to get the I2C address correct. If the wiring used on the backpack is different than what the library assumes, it will not work even if the correct i2c address is used.
This is nice because it allows the library work with any backpack. However, the user must correctly enter the pin mapping information. If the pin mapping information is incorrect, then it will not work.
Then you can look at the other hd44780_I2Cexp i/o class examples like HelloWorld, to see what files need to be included and how to declare your lcd object.
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