Arduino MKRFOX1200 COM port is not working

Question

I'm working on a project on a MKRFOX1200 board. I was using it today when suddenly, the COM3 port has stopped working, for an unknown reason ... I'm using windows 10, when it begin, the only things I modified in my code and I tried to upload were this lines (at different places in the code):

#include <RTCZero.h>

rtc.begin();

rtc.setTime(0,0,0);
rtc.setAlarmTime(0,0,10);
rtc.enableAlarm(rtc.MATCH_HHMMSS);

rtc.standbyMode();

I tried to comment then right after to see if they were the problem, but no. I tried to connect/disconnect the USB cable from my computer and from the board, I restarted my computer, I tried to reset the board with the hard button and with the reset pin, I disconnected all the cable that I connected to the board, I re-installed the drivers, but nothing to do ... Sometimes, a led slowly blink on the board and my computer recognize it as "Arduino MKRFOX 1200 (bootloader)", but the arduino IDE is still not able to tranfer my code on it. The error displayed by the arduino IDE is this:

Arduino : 1.8.5 (Windows Store 1.8.10.0) (Windows 10), Carte : "Arduino MKR FOX 1200"

Le croquis utilise 12592 octets (4%) de l'espace de stockage de programmes. Le maximum est de 262144 octets.
Redémarrage forcé en cours en 1200bps ouvert/fermé sur le port COM3
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
PORTS {COM3, } / {COM3, } => {}
Uploading using selected port: COM3
C:\Users\noe\Documents\ArduinoData\packages\arduino\tools\bossac\1.7.0/bossac.exe -i -d --port=COM3 -U true -i -e -w -v C:\Users\noe\AppData\Local\Temp\arduino_build_137596/projetFinalMKR.ino.bin -R 
No device found on COM3
Une erreur est survenue lors du transfert du croquis

Some of this report are in french because my IDE is in french, if I try to translate it in English, it's:

No device found on COM3, an error as occured while transferring sketch

At the beginning, I there is something written that I didn't really understood:

Forced reboot in progress at 1200bps open/close on the port COM3

I read a lot of forum topics about the same problem but every time, it was a driver problem, that didn't solved anything for me ... I'm afraid that something in the code is making the COM port busy, but I don't know how to erase it, or to switch on the board without launching it.

NOEBOU NOEBOU · Accepted Answer · 2018-06-12T14:53:12

I think I found a kind of a solution, if someone have to deal with the same problem, maybe It will be useful:

I tried to transfer a basic sketch (blink) on the board. I firt put down the reset hard button, click to the transfer button, and put up the reset hard button while compiling. I did this like at least 30 times and it miraculousely worked the 31st one. I think you have to do it at the exact perfect timing, when the serial port initialize itself whithout launching the code.

Oh and I used this version of the arduino IDE: https://blockly.technologiescollege.fr/forum/index.php?topic=37.0 (the link in the lastest message)

Good luck to everyone facing the same problem ! (I think it came from the RTC library ...)

Arduino MKRFOX1200 COM port is not working

2 Answers