I have been using the Arduino Web Editor when I am teaching children. It works great with the Arduino UNO, I have the impression it compiles and upload even faster than the Arduino IDE. On the other hand, with the M0 I get the following messages while uploading, and it takes a couple minutes to complete:
Restarting in bootloader mode
Get port list before reset
[COM4]
Touching port COM4 at 1200bps
Set DTR off
Flashing with command:C:/Users/.arduino-create/arduino/avrdude/6.3.0-arduino9/bin/avrdude.exe -CC:/Users/.arduino-create/arduino/avrdude/6.3.0-arduino9/etc/avrdude.conf -patmega2560 -cstk500v2 -PCOM20 -b57600 -Uflash:w:C:/Users/AppData/Local/Temp/arduino-create-agent209593565/DemoReel100.hex:i
avrdude: AVR device initialized and ready to accept instructions
Reading | ################################################## | 100% 0.00s
avrdude: Device signature = 0x1e9801 (probably m2560)
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: NOTE: "flash" memory has been specified, an erase cycle will be performed
To disable this feature, specify the -D option.
avrdude: erasing chip
avrdude: reading input file "C:/Users/AppData/Local/Temp/arduino-create-agent209593565/DemoReel100.hex"
avrdude: writing flash (42980 bytes):
Writing | ################################################## | 100% 0.28s
avrdude: 42980 bytes of flash written
avrdude: verifying flash memory against C:/Users/AppData/Local/Temp/arduino-create-agent209593565/DemoReel100.hex:
avrdude: load data flash data from input file C:/Users/AppData/Local/Temp/arduino-create-agent209593565/DemoReel100.hex:
avrdude: input file C:/Users/AppData/Local/Temp/arduino-create-agent209593565/DemoReel100.hex contains 42980 bytes
avrdude: reading on-chip flash data:
Reading | ################################################## | 100% 0.27s
avrdude: verifying ...
avrdude: 42980 bytes of flash verified
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: stk500v2_ReceiveMessage(): timeout
avrdude: safemode: Fuses OK (E:50, H:58, L:50)
avrdude done. Thank you.
Any suggestions what could be wrong?