Input power affecting code?

Development Boards Arduino
1

I had added some code to an existing program where it would read the battery voltage and display it on a LCD. When my UNO is plugged into the usb the display shows the “Battery Power…” code. When the UNO is on external power, there is a long blank pause where the battery display should show, then runs the rest of the proggie.

Both cases the LCD gets power from the UNO.

The external power supply is a 12volt battery pack through a filtered power supply.

Battery level ref is from a voltage divider from the 12volt battery pack.

This is the only time I have ever noticed this phenomenon and have had it do this to two different unos.

Any Ideas?

2

Show us a schematic of the power to ADC circuit.

Also your code that reads the ADC and the conversion to display.