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Topic: Leonardo uploads and runs, but no Serial (USB) output (Read 1 time) previous topic - next topic


I've read the troubleshooting guide, and searched for similar issues.  Nothing quite matches my issue. 

I can upload and run sketches, and my Leonardo USB enumerates to a COM port that I can connect to, but I can't get any serial output from that Leonardo COM port. 

  • Blink uploads and runs fine.

  • (Hardware) Serial1 (pins 0 and 1) works fine to my FTDI cable (shows up as COM4 on my system).

  • Leonardo enumerates to COM6 when plugged in or reset. 

  • The Leonardo has nothing plugged into it except the USB cable and ISP programmer. 
  • The programmer is genuine Atmel JTAGICE3 and it's clearly working (Blink uploads and runs).

  • I use Atmel Studio 6 for development (clearly working with this board and my other Arduino variants).

  • Unplugging the programmer and resetting the Leo doesn't help.

  • Device Manager (Windows 7 64) indicates the Leonardo com port/driver is working fine.

  • I got the Leonardo driver from the Arduino 1.0.1 distribution.
  • I can see and connect to either of the above listed COM ports in my terminal software (Brays Terminal v1.9b).

  • Terminal shows expected output from COM4 (FTDI / Serial1), but nothing when connected to COM6.

  • I figured out that the loopback test can't work on the Leonardo variant, but I don't see that documented anywhere.

  • The Arduino itself is an Olimex Olimexino32u4 (Leonardo clone).

What am I overlooking? 

Here's my test code:
Code: [Select]

#include <Arduino.h>

int led = 9;

void setup() {
pinMode(led, OUTPUT);
Serial.begin(9600); //speed is apparently irrelevant

void loop() {
digitalWrite(led, HIGH);   // turn the LED on (HIGH is the voltage level)
delay(1000);               // wait for a second
digitalWrite(led, LOW);    // turn the LED off by making the voltage LOW
delay(1000);               // wait for a second
Serial.println("test");      //doesn't work (Leonardo USB)
Serial1.println("test2");   //works great (pin 0, 1)


I'm drowning here, guys.  Should I have posted this somewhere else?   

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