How are the ATA(-2,PI) I/O ports assigned?
The registers of the primary ATA channel occupy the following I/O addresses (in hexadecimal notation): Register Read Function Write Function 01F0h Read Data Write Data (16 Bits) (16 bits) 01F1h Error register Set Features Data 01F2h Status of sector Write sector count count for command setup 01F3h Location of starting Write sector start sector for command setup 01F4h Location of Cyl-low Write cyl-low location for command setup 01F5h Location of Cyl-high Write cyl-high location for command setup 01F6h Head/device selection Write device selection and head selection for command setup 01F7h Device Status Device command 03F6h Alternate Status Device Control 03F7h Drive Address Note that the floppy disk controller’s disk change flag shares 03F7h which makes life difficult for designers that want to implement disk and floppy controllers separately. From this point of view it may come as no surprise that some of the problems in the CMD640x and RZ1000 ‘EIDE’ interface chips touched upon elsewhe
