DUE Boot up issue

I have a DUE (clone), which has started to behaive a bit oddly, wondering if this is normal

what has been observed is thus:

  • power on the DUE, either with a USB lead or an external supply
  • board powers up but does not boot, most outputs appear to be logic high, for example LED driver circuits (transitor drives) are activated, output appears to be low but not "LOW", and high enough to trigger the drivers
  • board can sometimes be brought to life with a press of the reset button, othertimes it appears to have lost its programme.


  • when actually running an attempt to reprogramme the board will fail, however then pressing reset will cause the board back into the stalled state noted above, then it can be re-programmed

the board is connected to another (WeMos) with a common power supply and a serial link (which has a toggle to isolate it) between Serial1 and the WeMos, it is noted that with the serial link isolated that programming the WeMos when both boards are on USB power will also cause the "stalled" state when the DUE reboots - external power avoids this until that power is removed, then when re-applied the board stalls once more

Q: is this a possible power regulator issue on the DUE? & would providing an external 3.3v supply (current supply is 9v via the barrel jack) help avoid this?

Q: is this a sign of a board on its way out that needs retiring?

There is somewhere a long thread "DUE does not restart after power up" with multiple solutions.

Usually a simple resistor between Reset and GND will do the job, or even better, a delay(1000); right at the beginning of setup() will do the job if you plug/unplug/plug the USB cable.

If you can't upload a new sketch, push the Erase button for 3 seconds, then the Reset button for 3 seconds and try again to upload a new sketch.

ahhh yes, have found it now.

cheers, will have a fiddle :slight_smile: