Bricked Serial Port? Hard Reset? (Solved: Double Tap Reset)

Official Hardware Pro Solutions Portenta Machine Control
1

Good afternoon, I've just started with this board and was playing around, it looks like I've blocked the serial port and won't connect to the PC anymore.
Is there a way to do a hard reset or wipe the code so I can reconnect?

1 Like
2

Can you explain your problem in more detail? What is arduino board you using? What is ypur PC operation system?

3

I'm using the Portenta Machine Control, programing with Win 11.

The serial port seems to have locked up (or just not working properly) and is unrecognized by the PC giving a Device Descriptor Request Failed error. At this point I can no longer communicate with it and am unable to upload a new sketch.

4

Did this board worked on this computer before?

5

Yes, same PC I've been using to program it. I've only had it a few days and only been doing some initial testing in the lab, nothing else hooked up at this time.

6

I also tried with another PC to double check with the same result.

7

Unfortunately, I don't know Portenta very well.
Is there a button on the board like "Boot" to force the controller to switch to boot mode? If so, try to connect the board to USB with the button pressed.

8

Not that I'm aware of, I tried holding the reset, which is the only on-board button that I see.

9

SOLVED: Double Tapping the Reset button forces it to enter "bootloader mode", and I was able to upload a new sketch.

10

So I was close to the solution in post #7 :slight_smile:

11

Yes, reset button as single press - a regular reset (or you do a power cycle):
Pressing reset twice - it enters bootloader:
the serial UART is gone (now an UART for bootloader - see in Device Danager or the COM port available - a different one).

Bootloader is a different UART (port). Watch the LED: if fading flashing green - the bootloader has been entered (and user UART gone, COM device disappeared for user UART, now a COM for bootloader).,
I think you need a power cycle to exit the bootloader mode (any further reset remains in bootloader mode) - if you accidently have entered bootloader mode: no need to flash again if all was OK, just exit bootloader via power cycle (but potentially wait 10sec. for repowering the board, some settings "survive" a short power outage).