COM Port / Communication problem

Hi !
I used in a program the LowPower.sleep. Uploading a new version of the program resulted in communication errors.

I read that the solution is a double click on the reset button. However that did not work in my case.

It seems that you have to do the double click at the right moment:

When you try to upload a new program you will see normally the following messages:

-->
...

Touching port /dev/cu.usbmodem1D1331 at 1200bps

Set DTR off

Flashing with command:/Users ...

<---

Try to do the double click quickly after the message "Set DTR off" appears. That will be just before the flashing occurs. The flashing will otherwise time out after half a minute or so if the device is in sleep. Doing the double click right now get the device out of sleep - I think !

Good Luck

There were similar issues with the MKR1000.

Maybe there are a few useful threads in that section.