Joel Linn

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8 years, 8 months ago.

2 LED Blinky weird behaviour

Got an LPC800-Max board.

Instead of blue and green blinking after each other with a 1 second black gap, in the 1 second gap both leds are on (sequence is blue lightblue green lightblue in a loop) I can't explain this so please try to explain.. :/

#include "mbed.h"

DigitalOut ledB(LED1);
DigitalOut ledG(LED2);

int main() {
    while(1) {
       ledB = 1;
       wait(1);
       ledB = 0;
       wait(1);
       ledG = 1;
       wait(1);
       ledG = 0;
       wait(1);       
    }
}

2 Answers

Bill Bellis
8 years, 8 months ago.

That sounds correct. This is your code but using "OFF" and "ON" to help explain..

#include "mbed.h"
 
DigitalOut ledB(LED1);
DigitalOut ledG(LED2);
 
#define OFF 1
#define ON 0
int main() {
    while(1) {
       ledB = OFF;
       wait(1);
       ledB = ON;
       wait(1);
       ledG = OFF;
       wait(1);
       ledG = ON;
       wait(1);       
    }
}

Andy A
8 years, 8 months ago.

Are your LED pins active low? It's quite common to wire LEDs up so that you output 0 to turn them on and 1 to turn them off.