I made a custom board with 2 ATSAMD10D13AM parts. The are 8k flash/4k sram Cortex-M0 24QFN parts. When I power the board the IC's start but then freeze (I have LED's blinking that go solid). When I attach the debugger and start debugging, it runs fine. The debugger senses power and does not supply it. The code is modified reference design code for the Xplained Mini, it uses the same part except 16k flash. I am pretty sure I changed the part everywhere. I think maybe the ramp isn't perfect. It is supposed to be 25us or greater from 0 to 2.5V. I will measure it with a scope. Otherwise what could it be?