Has anyone seen this issue... I have an uno board, connected to windows XP. I am connected with the USB cable with a simple connection of three wires in ports 2,3,4 that are running to 2 - 8 bit shift registers running 16 LED's. I am creating a binary clock.
The code runs through shifting the registers based on the time. When I am connected through the USB it will upload and try to run. The lights will start flashing and then it seems to reset and flash again, over and over. If I open the serial monitor it then runs correctly.
If I unplug the USB and then run it off of a 9v power supply it also runs correctly.
Any ideas?