Tutorial: How to use the Serial port on mbed

On this tutorial, we will show how to send messages using the serial communication. The mbed has 3 serial ports that can be configured. This can be used to communicate with other ICs or for debug purposes. Also, the board has a serial port that can be emulated via USB:

Connect the mbed to your PC. Open the compiler as in http://garagelab.com/profiles/blogs/tutorial-mbed-first-steps. Open that link and import that library to the program.

Inside the main.cpp file, paste the code:

#include "mbed.h"

Serial pc(USBTX, USBRX); // tx, rx
PwmOut led(LED1);

float brightness = 0.0;

int main() {
pc.printf("Press 'u' to turn LED1 brightness up, 'd' to turn it down\n");

while(1) {
char c = pc.getc();
if((c == 'u') && (brightness < 0.5)) {
brightness += 0.01;
led = brightness;
if((c == 'd') && (brightness > 0.0)) {
brightness -= 0.01;
led = brightness;


Open a serial terminal program, like PuTTY:

When you press u the onboard LED will get brighter, if you press d, it will fade out.

That's it! Enjoy using your board with serial communication.





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Tags: mbed, serial, tutorial


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