Arduino Nano 33 BLE - forced to reset after every upload

Development Tools IDE 2.x
1

Hi everyone,
I've just got my new Arduino Nano 33 BLE.
blink example etc all works great, except for one problem with uploading.

Every time when I upload, the board goes into LED flashing mode (aka bootloader mode).
After it, I'm forced to tap the reset button once to make the new code apply on the board. I assume it's not the way how it's intended to work.

My system setup:

  • MacOS 13.4.1, 2,2 GHz 6-Core Intel Core i7
  • Arduino IDE info:
Version: 2.1.0
Date: 2023-04-19T15:26:42.115Z
CLI Version: 0.32.2

Any clues on what's wrong with this setup?

I might assume that something is not okay with the USB connection - I'm using the standard USB connector that was coming together with the board, and I first plug it into a USB to USB-C converter and then plug this converter into Mac.

2

Upd. - it seems like the process is inconsistent.

Sometimes It works without any problems:

  • the bootloader blinks only when the Upload stage is happening
  • After the upload the bootloader stops blinking and the board starts working with the new code version.

But sometimes (and it's quite randomly, out of 5 tries 3 were successful and 2 were unsuccessful) it works only in the following way:

  • the bootloader blinks during the upload stage
  • after the upload stage the board is still in bootloader mode.

In this case, I'm forced to click the reset button. This is indeed very inconvenient, and it will make development almost impossible as soon as the board will be packaged into a container.
Any advice on the topic would be quite helpful.

3

Hi @renardeinside

There are two different LED signalling behaviors the Nano 33 BLE might present, each of which has a distinct meaning. Please tell us which of these two behaviors are you seeing?:

  • Pulsing (LED brightness fades in and out)
  • A cycle of four blinks (LED switching instantaneously from an off state to full brightness) at a long interval followed by four blinks at a short interval, repeating.
4

Hi @ptillisch
it's pulsing (LED brightness fades in and out). Do I understand correctly it means that the board went into bootloader mode (or it didn't leave after upload)?

5

That is correct.

Do you have Serial Monitor, Serial Plotter, or any other application configured to connect to the port at 1200 baud? This baud rate has a special significance because the board sees a connection at that specific baud rate as a signal to activate the bootloader in preparation for an upload. I found I was able to produce behavior similar to what you report by uploading while I had "1200 baud" selected from the menu in the Arduino IDE Serial Monitor.

6

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