Mode-selectable integrated disk drive for computer

摘要

An interface between a CPU bus and peripheral device such as a standard embedded controller disk drive uses either a dedicated, I/O mapped register set for control and status communication between the host CPU and the disk controller, or an alternate "flex mode" protocol which allows the drive to be used with great versatility in a wide variety of systems. This alternate "flex mode" protocol does not require changes to the hardware definition of the drive interface, but instead uses the data port to transfer information blocks to set up a subsequent data transfer through this port.