lcd module 20x4 i2c manufacturer

The LCD has always been a device that acts as a window in human-computer interaction. For example, the prompt window on some instrument devices, the temperature and humidity prompt box, the device running status monitor, and the prompt screen of the counting device all have LCD figures.

It is a high-performance serial bus with bus rules and high-speed or low-speed device synchronization required for multi-master systems. The I2C bus has only two bidirectional signal lines, a serial data line (SDA) and a serial clock line (SCL).

If you’ve ever tried to connect an LCD display to an Arduino, you might have noticed that it consumes a lot of pins on the Arduino. Even in 4-bit mode, the Arduino still requires a total of seven connections – which is half of the Arduino’s available digital I/O pins.

The solution is to use an I2C LCD display. It consumes only two I/O pins that are not even part of the set of digital I/O pins and can be shared with other I2C devices as well.

True to their name, these LCDs are ideal for displaying only text/characters. A 16×2 character LCD, for example, has an LED backlight and can display 32 ASCII characters in two rows of 16 characters each.

At the heart of the adapter is an 8-bit I/O expander chip – PCF8574. This chip converts the I2C data from an Arduino into the parallel data required for an LCD display.

If you are using multiple devices on the same I2C bus, you may need to set a different I2C address for the LCD adapter so that it does not conflict with another I2C device.

An important point here is that several companies manufacture the same PCF8574 chip, Texas Instruments and NXP Semiconductors, to name a few. And the I2C address of your LCD depends on the chip manufacturer.

According to the Texas Instruments’ datasheet, the three address selection bits (A0, A1 and A2) are placed at the end of the 7-bit I2C address register.

According to the NXP Semiconductors’ datasheet, the three address selection bits (A0, A1 and A2) are also placed at the end of the 7-bit I2C address register. But the other bits in the address register are different.

So your LCD probably has a default I2C address 0x27Hex or 0x3FHex. However it is recommended that you find out the actual I2C address of the LCD before using it.

Connecting an I2C LCD is much easier than connecting a standard LCD. You only need to connect 4 pins instead of 12. Start by connecting the VCC pin to the 5V output on the Arduino and GND to ground.

Now we are left with the pins which are used for I2C communication. Note that each Arduino board has different I2C pins that must be connected accordingly. On Arduino boards with the R3 layout, the SDA (data line) and SCL (clock line) are on the pin headers close to the AREF pin. They are also known as A5 (SCL) and A4 (SDA).

After wiring up the LCD you’ll need to adjust the contrast of the display. On the I2C module you will find a potentiometer that you can rotate with a small screwdriver.

Plug in the Arduino’s USB connector to power the LCD. You will see the backlight lit up. Now as you turn the knob on the potentiometer, you will start to see the first row of rectangles. If that happens, Congratulations! Your LCD is working fine.

To drive an I2C LCD you must first install a library called LiquidCrystal_I2C. This library is an enhanced version of the LiquidCrystal library that comes with your Arduino IDE.

Filter your search by typing ‘liquidcrystal‘. There should be some entries. Look for the LiquidCrystal I2C library by Frank de Brabander. Click on that entry, and then select Install.

The I2C address of your LCD depends on the manufacturer, as mentioned earlier. If your LCD has a Texas Instruments’ PCF8574 chip, its default I2C address is 0x27Hex. If your LCD has NXP Semiconductors’ PCF8574 chip, its default I2C address is 0x3FHex.

So your LCD probably has I2C address 0x27Hex or 0x3FHex. However it is recommended that you find out the actual I2C address of the LCD before using it. Luckily there’s an easy way to do this, thanks to the Nick Gammon.

But, before you proceed to upload the sketch, you need to make a small change to make it work for you. You must pass the I2C address of your LCD and the dimensions of the display to the constructor of the LiquidCrystal_I2C class. If you are using a 16×2 character LCD, pass the 16 and 2; If you’re using a 20×4 LCD, pass 20 and 4. You got the point!

First of all an object of LiquidCrystal_I2C class is created. This object takes three parameters LiquidCrystal_I2C(address, columns, rows). This is where you need to enter the address you found earlier, and the dimensions of the display.

In ‘setup’ we call three functions. The first function is init(). It initializes the LCD object. The second function is clear(). This clears the LCD screen and moves the cursor to the top left corner. And third, the backlight() function turns on the LCD backlight.

After that we set the cursor position to the third column of the first row by calling the function lcd.setCursor(2, 0). The cursor position specifies the location where you want the new text to be displayed on the LCD. The upper left corner is assumed to be col=0, row=0.

There are some useful functions you can use with LiquidCrystal_I2C objects. Some of them are listed below:lcd.home() function is used to position the cursor in the upper-left of the LCD without clearing the display.

lcd.scrollDisplayRight() function scrolls the contents of the display one space to the right. If you want the text to scroll continuously, you have to use this function inside a for loop.

lcd.scrollDisplayLeft() function scrolls the contents of the display one space to the left. Similar to above function, use this inside a for loop for continuous scrolling.

If you find the characters on the display dull and boring, you can create your own custom characters (glyphs) and symbols for your LCD. They are extremely useful when you want to display a character that is not part of the standard ASCII character set.

CGROM is used to store all permanent fonts that are displayed using their ASCII codes. For example, if we send 0x41 to the LCD, the letter ‘A’ will be printed on the display.

CGRAM is another memory used to store user defined characters. This RAM is limited to 64 bytes. For a 5×8 pixel based LCD, only 8 user-defined characters can be stored in CGRAM. And for 5×10 pixel based LCD only 4 user-defined characters can be stored.

After the library is included and the LCD object is created, custom character arrays are defined. The array consists of 8 bytes, each byte representing a row of a 5×8 LED matrix. In this sketch, eight custom characters have been created.

Features：IIC/I2C interface was developed to reduce the IO port usage on Arduino board.* Old 1602 screen requires 7 IO ports but this module uses only two.* Much needed control panel IO ports can be used to add some sensors, SD card and so on.* A New High-Quality 4 Line 20 Character Lcd Module.* Potentiometer can be adjusted to control the contrast.* Back light can be turned off by removing the jumper on the back panel.Specification:* Interface: I2C* I2C Address: 0x27* Pin Definition : GND、VCC、SDA、SCL* Back lit (Yellow with Black char color)* Supply voltage: 5V* Size : 60mm×99mm* Contrast Adjust : Potentiometer* Backlight Adjust : Jumper

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.

This module is an Arduino compatible LCD display module with high speed I²C interface. It can display 20×4 characters (white characters on a blue background).

This IIC/I2C/TWI Serial 2004/20x4 LCD Module Shield for Arduino Uno/Mega2560 displays white contents on an elegant blue. It can display 4 rows with 20 characters for each. With IIC/I2C interface, it only takes two I/O ports thus saving more for other usages.

The display is composed of a 20 character x 4 line LCD display with a blue backlight and white characters.  Each of the characters are composed of a 5 x 8 dot matrix for good character representation.

The backlight intensity is not directly controllable though the I2C interface, however there is a jumper on the I2C board that supplies power to the backlight.  That jumper can be removed and a voltage applied to the header pin nearest the ‘LED’ markings on the board to provide power to the backlight separately.

The backlight can go down to about 3V before it goes out.  It is not known what the safe upper limit is for driving the LCD backlight so it is probably best not to exceed 5V by too much.  At 5V, the backlight draws about 30mA, so it should also be possible to drive it with a PWM pin off a uC to allow the display to be dimmed via software if desired.

This display incorporates an I2C interface that requires only 2 pins on a uC to interface with and it has good library support to get up and running fast.   The I2C interface is a daughter board attached to the back of the LCD module.

If you need to adjust I2C address to avoid a conflict, this can be done on the I2C adapter board on the back of the module.  There are 3 address jumper locations marked A0, A1, A2.  Normally these lines are pulled high.  If you bridge these pads, it grounds that address line.  If you were to bridge all 3 to ground, the address would be 0x20.  The range of all possible addresses spans from 0x20 to 0x27

These are good quality modules and should be in the parts bin of any hobbyist.  Because of the interactivity they provide, they are both fun to play with and useful for more serious projects.

You will find the raw 20×4 displays without the I2C interface being sold, but those have a parallel bus interface that requires many pins on the microcontroller to control, so it is generally best to stick with the I2C interface version like this one.

Note that the I2C address of the module we sell is 0x27 (39 decimal) but can be adjusted if needed as explained above.  The address will be printed on the label on the bag.