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3/6/2018 I2C LCD2004 - Wiki

http://wiki.sunfounder.cc/index.php?title=I2C_LCD2004 1/5

ntroduction

As we all know, though LCD and some other displays greatly enrich the man-machine interaction, they share a common weakness. When they are connected to a controller,

multiple IOs will be occupied of the controller which has no so many outer ports. Also it restricts other functions of the controller. Therefore, LCD2004 with an I2C bus is

developed to solve the problem.

I2C bus is a type of serial bus invented by PHLIPS. It is a high performance serial bus which has bus ruling and high or low speed device synchronization function required by

multiple host system. I2C bus has only two bidirectional signal lines, Serial Data Line (SDA) and Serial Clock Line (SCL). The blue potentiometer on the I2C LCD2004 is used to

adjust backlight to make it easier to display on the I2C LCD2004.

Test Experiment

Components

- 1 *SunFounder Mars board

- 1 * I2C LCD2004 module

- 1 * USB cable

- Several jump wires

Experimental Principle

In this experiment, we will let I2C LCD2004 display 4 lines characters by programming.

I²C (Inter-Integrated Circuit), pronounced I-squared-C, is a multi-master, multi-slave, single-ended, serial computer bus invented by Philips Semiconductor (now NXP

Semiconductors). It is typically used for attaching lower-speed peripheral ICs to processors and microcontrollers. Alternatively I²C is spelled I2C (pronounced I-two-C) or IIC

(pronounced I-I-C).

I²C uses only two bidirectional open-drain lines, Serial Data Line (SDA) and Serial Clock Line (SCL), pulled up with resistors. Typical voltages used are +5 V or +3.3 V although

systems I²C (Inter-Integrated Circuit), pronounced I-squared-C, is a multi-master, multi-slave, single-ended, serial computer bus invented by Philips Semiconductor (now NXP

Semiconductors). It is typically used for attaching lower-speed peripheral ICs to processors and microcontrollers. Alternatively I²C is spelled I2C (pronounced I-two-C) or IIC

(pronounced I-I-C).

I²C uses only two bidirectional open-drain lines, Serial Data Line (SDA) and Serial Clock Line (SCL), pulled up with resistors. Typical voltages used are +5 V or +3.3 V although

systems with other voltages are permitted.

For more information about I2C operation principle, please visit I²C .

Experimental Procedures

Step 1: Connect the circuit

See the following table for connection between the I2C LCD2004 and the SunFounder Uno board:

I2C LCD2004 SunFounder Mars board

GND GND

VCC 5V

SDA A4 /pin 20 mega2560

SCL A5 /pin 21 mega2560

Step 2:Add library

Before you upload the code to the control board,you neeed to add the LiquidCrystal_I2C library.

1) Download the LiquidCrystal_I2C library

2) Open the Arduino IDE,Select Sketch -> Include Library -> Add ZIP Library

Summary of content (5 pages)

PAGE 1
3/6/2018 I2C LCD2004 - Wiki ntroduction As we all know, though LCD and some other displays greatly enrich the man-machine interaction, they share a common weakness. When they are connected to a controller, multiple IOs will be occupied of the controller which has no so many outer ports. Also it restricts other functions of the controller. Therefore, LCD2004 with an I2C bus is developed to solve the problem. I2C bus is a type of serial bus invented by PHLIPS.
PAGE 2
3/6/2018 I2C LCD2004 - Wiki 3) Find the file LiquidCrystal_I2C which you just download. Click it open and then you'll be prompted by "Library added to your libraries. Check 'Import libraries'”. You also can see the libraries just imported have appeared on the list by Sketch->Include Library->LiquidCrystal_I2C.
PAGE 3
/6/2018 I2C LCD2004 - Wiki lcd.print(" 20 cols, 4 rows "); // pad with spaces for centering lcd.setCursor ( 0, 3 ); // go to the fourth row lcd.print(" www.sunfounder.com "); } /*********************************************************/ void loop() { } /************************************************************/ Step 4: Upload the code Before upload the code ,you need to select correct Board and Port,please follow the steps: 1) Click Tools ->Board and select Arduino/Genuino Uno.
PAGE 4
3/6/2018 I2C LCD2004 - Wiki Read I2C Address If everything is correct,But the display just shows 16 black rectangles on Line 1.it may be the address of i2c is not 0x27,therfore you need to run the following code to read the address,then modify the 0x27 to which you read.
PAGE 5
3/6/2018 I2C LCD2004 - Wiki } else if (error==4) { Serial.print("Unknow error at address 0x"); if (address<16) Serial.print("0"); Serial.println(address,HEX); } } if (nDevices == 0) Serial.println("No I2C devices found\n"); else Serial.println("done\n"); delay(5000); // wait 5 seconds for next scan } Change I2C Address When a conflict happens on the I2C address, you can change the I2C address by setting the A0, A1, A2 pins to 1 or 0 on the PCF8574 chip.