Abstract: A synchronizer for passing data from a first system that transmits data based on a first clock and a second clock, to a second system that receives data based on a third clock, includes a first set of flip-flops for receiving data from the first system based on the first clock. The synchronizer includes a second set of flip-flops for receiving data from the first system based on the second clock. The synchronizer includes a first multiplexer coupled to outputs of the flip-flops in the first and the second set. The synchronizer includes a controller for controlling the first multiplexer to output data from selected ones of the flip-flops based on the third clock, thereby generating output data to be provided to the second system.