RGB LED interfacing with MSP430G2 LaunchPad




In this tutorial, you will get to know how to interface RGB LED with MSP430G2 LaunchPad . In this first tutorial about MSP430G2 LaunchPad , we have seen overview of MSP430G2 LaunchPad  and we have also seen how to use Energia IDE to program MSP430G2 board. I suggest you to through these tutorials first to get better understanding of this guide on multi color light emitting diode interfacing with MSP430G2 LaunchPad .




  1. Getting started with MSP430G2 LaunchPad 
  2. How to use input output ports of MSP430G2 LaunchPad 

To interface RGB LED with MSP430G2553 microcontroller, you should first know that how to configure input output pins or general purpose input output pins as a digital output pins. These pins are also known as GPIO pins.  So now lets start with basic introduction of RGB light emitting diode and its pin description etc.

Introduction to RGB LED interfacing with MSP430G2 LaunchPAD

So now we are going to learn how to use an RGB LED with MSP430G2 board a very interesting type of LED as you will see. We will connect  this led to an MSP430 and every second it will change its color that’s very handy because we can use only one LED in our projects and produce many colors. So now lets see what is RGB LED?RGB LED pinout

what is an RGB LED? A light-emitting diode which can display any color we want. It consists of three discreet LEDs RED, green and a blue LED housed in a single packets so by combining these three colors we can create any color. As you can see in the picture above the RGB LED has four pins so far the LEDs we were using only had two pins. These pins are used in order to control the color of the LED.  The longest pin is either the anode or the cathode depending on the type of the RGB LED. common Anode and Common Cathode RGB LED




The LED we are using in this tutorial is a common cathode LED so the longest leg will be connected to ground.  if it was a common anode LED the long  pin will connect to five volts. The other three pins are red green and blue.

How to interface RGB LED with MSP430G2 LaunchPad

Let’s connect this RGB LED to MSP430G2 LaunchPad and see how to make it work. The parts that we are going to need for this tutorial are the following:

  • MSP430G2 LaunchPad
  • RGB LED
  • 3 330 ohm resistors
  • a small breadboard
  • some wires
In order to limit the current that will run through the RGB LED , we need to use three resistors one for its color pin if we do not use a resistor or if we use a low resistor the LED will be destroyed.  We need to use a 330 ohm resistor or higher. The higher the resistor value, lower the brightness of the LED. So the resistor value is 330 ohms. Now all we have to do is to connect the RGB LED with MSP430G2 LaunchPad.  Circuit for interfacing with RGB LED is shown below: RGB LED interfacing with MSP430G2 LaunchPad

Now make the connection according to this circuit diagram. I am using a RGB module which has on board three resistors connected with all three pins red, green and blue. But you can make the circuit according to these connection by connecting 330 ohm resistor before red, green and blue pins and connect pin number 2 to ground.

  • RED PIN –  PIN NUMBER 13
  • GREEN PIN –  PIN NUMBER 14
  • BLUE PIN –  PIN NUMBER 15

How to write code for RGB LED

For demonstration purpose, I have written this code for RGB LED control. In this code, we are turning on RED led for once second, Green LED for one second and at the end red led for once second. Now lets see how this code works.  In this first three lines we have given names to pin number 13, 14 and 15 which are used to connect with red, green and blue pins of RGB LED. In the setup function pin mode function initialized all three pins as a output.

int redPin= 13;

int greenPin =14;

int bluePin = 15;

void setup() {

  pinMode(redPin, OUTPUT);

  pinMode(greenPin, OUTPUT);

  pinMode(bluePin, OUTPUT);

}

void loop() {

  setColor(1, 0, 0); // Red Color

  delay(1000);

  setColor(0, 1, 0); // Green Color

  delay(1000);

  setColor(0, 0, 1); // Blue Color

  delay(1000);

}

void setColor(int redValue, int greenValue, int blueValue) {

  digitalWrite(redPin, redValue);

  digitalWrite(greenPin, greenValue);

  digitalWrite(bluePin, blueValue);

}

Now  upload the code to MSP430G2 board and see how it works. you will see first RGB LED is emitting RED light and then green and then blue light. This is how easy it is interface RGB LED with any microcontroller or MSP430G2 launch Pad.



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