Help - My NanosG20 does not boot anymore

The NanosG20 uses the WAKEUP/SHUTDOWN mask of the AT91SAM9G20 microcontroller. On a regular shutdown the enable pin of the power regulator is toggeled and can be switched back by WAKEUP. WAKEUP is connected to the switch on your NanosG20. On a regular shutdown, you have to press the switch to boot your Nanos. On failure the Nanos would boot without the switch. The register settings for WAKEUP/SHUTDOWN are battery backed-up. So they persist between reboots and connecting or disconnecting the power cable, when a battery is connected.
So, when your NanosG20 does not boot:

  • First make sure, that the your power adaptor is connected with X14 between the DSUB-9 connectors. If you connect via the USB-Device port X7, J9 has to be set. Please guard not connecting both connectors at a time, when J9 is set
  • Press the switch to boot your device. If you keep the switch pressed, you will end in the boot menu.
  • The WAKEUP/SHUTDOWN mimic is locked. This can happen, if you changed the battery or battery current was interrupted. Disconnect the power adaptor. Disconnect the battery, e.g. with a slip of paper. Connect the power adaptor again and remove then the slip of paper. Your Nanos should boot now.
  • If this mimic does not fit your application, you can use J5 to disable this feature altogether. For revision 2 J5 has to be closed when using NanosG20 without backup battery.