I need to restart Arduino IDE after each compilations

Question

I'm using the Arduino Due and testing an I2C Scanner, the I2C Scanner works correctly but each time I want to upload a newer version of the code I get this error message :

No device found on COM11
Send auto-baud
Set binary mode

What I need to do in this case is : remove USB, restart the Arduino IDE, reconnect USB, then it works again, one time...

It seems related to this problem : Serial port on mac only works after restarting arduino IDE

I'm not sure but What's maybe also symptomatic is I need to systematically push the restart Button of my board in order to receive something in the Serial Monitor, could it be related ?

Here is the I2C Scanner code I'm using :

// --------------------------------------
// i2c_scanner
//
// Version 1
// This program (or code that looks like it)
// can be found in many places.
// For example on the Arduino.cc forum.
// The original author is not know.
// Version 2, Juni 2012, Using Arduino 1.0.1
// Adapted to be as simple as possible by Arduino.cc user Krodal
// Version 3, Feb 26 2013
// V3 by louarnold
// Version 4, March 3, 2013, Using Arduino 1.0.3
// by Arduino.cc user Krodal.
// Changes by louarnold removed.
// Scanning addresses changed from 0...127 to 1...119,
// according to the i2c scanner by Nick Gammon
// http://www.gammon.com.au/forum/?id=10896
// Version 5, March 28, 2013
// As version 4, but address scans now to 127.
// A sensor seems to use address 120.
// Version 6, November 27, 2015.
// Added waiting for the Leonardo serial communication.
//
//
// This sketch tests the standard 7-bit addresses
// Devices with higher bit address might not be seen properly.
//
#include <Wire.h>
void setup()
{
 Wire.begin();
 Serial.begin(9600);
 while (!Serial); // Leonardo: wait for serial monitor
 Serial.println("\nI2C Scanner");
}
void loop()
{
 byte error, address;
 int nDevices;
 Serial.println("Scanning...");
 nDevices = 0;
 for(address = 1; address < 127; address++ )
 {
 // The i2c_scanner uses the return value of
 // the Write.endTransmisstion to see if
 // a device did acknowledge to the address.
 Wire.beginTransmission(address);
 error = Wire.endTransmission();
 if (error == 0)
 {
 Serial.print("I2C device found at address 0x");
 if (address<16)
 Serial.print("0");
 Serial.print(address,HEX);
 Serial.println(" !");
 nDevices++;
 }
 else if (error==4)
 {
 Serial.print("Unknown error at address 0x");
 if (address<16)
 Serial.print("0");
 Serial.println(address,HEX);
 } 
 }
 if (nDevices == 0)
 Serial.println("No I2C devices found\n");
 else
 Serial.println("done\n");
 delay(1000); // wait 5 seconds for next scan
}

• Majenko: IDE version? Native or UART port?
• snoob dogg: IDE is 1.6.12, I use the Native port
• Majenko: And if you try the current version, 1.8.2?

Answer 1

I finally solved the problem, but it's really specific and I don't know if should be on Stack Exchange. Maybe it could give some clues if someone has a similar problem one day...

I was using pin 20 and 21 on my Arduino Due which are supposed to have built-in pull-up resistor. That's what I've read everywhere and it has been said again recently in the answer of an another question I've asked : How to chooce SDA/SCL pair on Arduino Due ?.

Solution : Since I'm using SDA1 / SCL1 with Wire1 everything works like a charm. The value I get from the device are correct, no need anymore to restart the board and I can recompile again and again without any problems.

Edit : In fact, it work significantly better but I still had to use pullup resistors with these inputs. The goal was to use the MPU 9250 and it seems more stable now.