JMicron JMB321 is a single chip. It integrated six  independent SATA channels and a micro-processor.

With proper setting, the chip can be configured as  an 1 to 5-ports Serial ATA II Port Multiplier or a  5 to 1-port Serial ATA II Port Selector.

JMB321  contains  15  GPIOs  which  can  be  configured  as various  standard  interfaces.  It also has  the capability to load external firmware code to extendits functionality.