A double-edge-triggered flip-flop scan cell. The double-edge-triggered flip-flop
scan cell provides the capability to capture and output data for each edge of a
clock signal in a functional mode of a host integrated circuit. In a test mode,
the double-edge triggered flip-flop scan cell enables test data to be scanned into
and out of the scan cell to provide observability and controllability of the scan
cell internal state.