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Topic: Leonardo Question (Read 886 times) previous topic - next topic



The question in the video is:

"LEDs are connected to most of the Arduino Leonardo pins. When I power up or reset some of the LEDs pulse for a few seconds (reportedly something the bootloader does).  Can I get rid of that and have it go straight to my sketch?  If so, how?"

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James C4S

Capacitor Expert By Day, Enginerd by night.  ||  Personal Blog: www.baldengineer.com  || Electronics Tutorials for Beginners:  www.addohms.com


Sorry, I thought posting a video would help facilitate the process, guess not. Thanks for posting the summary though, I really need to figure this out. I don't have a schematic but its really simple, just LEDS connected to pwm pins that fade on in succession. Here is the code I'm using:

Code: [Select]

int leds[] = {
int num = 7;

void init_leds(){
  for(int i = 0; i<num; i++){
    pinMode(leds[i], OUTPUT);     

void FadeOutLeds(){
  for(int i = 155;i>0;i--){

    for(int j = 0;j<num;j++){


void FadeInLed(int theLed){
  for(int i = 0;i<256;i++){

void setup() {               
  // initialize the digital pins as an output.

// the loop routine runs over and over again forever:
void loop() {

  for(int i = 0; i<num;i++){
  delay(5000);               // wait for 5 seconds

Im not certain a schematic would help anyway. Im not sure theres technically anything wrong, from what I've read about the Leonardo the bootloader takes 8 seconds to run which is exactly how long the first LEDs pulse for. I just need to know if theres a way to make them stop and have my project begin right away vs. having to wait 8 seconds before the above code is executed.


Modify the bootloader, or use an ISP programmer for all future programming.
Freelance engineer, consultant, contractor. Graduated from UW in 2013.

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