[SOLVED] Arduino micro clone - external power issues

Hi guys,

I've been struggling with an odd external power problem with my arduino micro clone with the Atmega32u4 for a few days now and I'm out of ideas. I haven't been able to find any solution on the forums so I'm hoping someone out there can help.

My board works as expected when plugged into the PC via USB. I can program the device normally and it runs as expected. The LED tied to D13 pulses on boot and once booted everything works fine and I can communicate to the device by serial.

Now when I power the device on Vin, everything looks as though its working, the LED pulses as expected then stops, but the board is unresponsive. I can't communicate to the device over serial. The only way I can get it to start talking is to plug it in to the USB port at which point the TX RX LEDs on the board light up and the device starts working as expected.

My initial thought was that I had external power supply issues, but I have tried the following with no success:

  • plugged USB into external power supply (not PC)
  • higher voltage Vin
  • different battery pack

Its worth noting that I'm trying to communicate with the device via software serial.

Any suggestions would be greatly appreciated.

Thanks

Are the grounds (of the micro and what it's talking to) connected? If not, they cannot communicate.

What voltage are you giving it on Vin? Due to dropout on the regulator, it needs at least 7v to power through Vin...

Where is the code?

DrAzzy: Are the grounds (of the micro and what it's talking to) connected? If not, they cannot communicate.

:blush: such a rookie mistake! Spot on, thanks for the suggestion