Pro Trinket Receives Power, Program Only Runs Using USB Power

Hi Arduino Forum,

This is my first post, thank you in advance for your help and patience.

Project: Miniature amusement park model

Board: Pro Trinket 5V 16mhz

Animation: 6 LED lights (in two groups of 3)

Power: A 12V bus, which powers the lights, Pro Trinket, and other elements of the model (motors)

Problem: Pro Trinket will only run the sketch when the micro USB is plugged in.

When powered through Bat + or VBat, the LED lights turn on, but there is no animation or program running.

I have tried both options of reprogramming the bootloader without any change.

Thanks again.


Have you figured out the issue yet? I was going to ask if you have one of the Pro's gnd pins tied to the 12v common.