The DONE pin indicates completion of configuration with standard approaches. DONE is also used for Tandem Configuration, but in a slightly different manner. DONE pulses High at the end of stage 1, when the start-up sequences are run. It returns Low when stage 2 loading begins. For Tandem PROM, this happens immediately because stage 2 is in the same bit file. For Tandem PCIe, this happens when the second bitstream is delivered to the PCIe MCAP interface. It pulls High and stays High at the end of the stage 2 configuration.