Method and apparatus for automatic phy calibration based on negotiated link speed

A serial ATA interface calibrates serially connected components of a computer system linked by the interface to a negotiated data transmission speed. The interface negotiates the fastest data transmission speed supported by the serially connected components. Link parameters associated with the negotiated data transmission speed are calibrated and implemented in a Phy layer of the interface before data is transmitted across the interface. The calibrated link parameters include signal transmission settings for amplitude, pre-emphasis, equalization and timing. Default settings of the link parameters correspond to the slowest data transmission speed supported by the serially connected components. The serially connected components are calibrated each time system power is initialized. The serially connected components can be a host computer linked to a data storage device such as a backplane-based storage subsystem.