Western Digital T13/2132-D - Manual (Page 62)

T13/2132-D Revision 3 June 23, 2010
50 Working Draft Enhanced Disk Drive - 4 (EDD-4)
8.20.2 Interface Path
The Interface Path field at offset 48 allows software external to a system BIOS to locate mass storage device
interface chips. The format of this field shall be dependent on the Host Bus type, offsets 36 through 39 of the
result buffer.
Table 23 — Interface Path Definitions (part 1 of 2)
Host Bus Type Offset Type Definition
ISA 48 Word 16-bit base address
50 Word Reserved
52 DWord Reserved
PCI 48 Byte PCI bus number. Values 00h through FEh shall represent a valid PCI bus.
Value FFh shall indicate that this field is not used.
49 Byte PCI slot number. Values 00h through FEh shall represent a valid PCI slot.
Value FFh shall indicate that this field is not used.
50 Byte PCI function number. Values 00h through FEh shall represent a valid PCI
function.
Value FFh shall indicate that this field is not used.
51 Byte Channel number. If more than one interface of the same type is accessed
through a single Bus, Slot, Function, then the channel number shall identify
each interface. If there is only one interface, the content of this field shall be
cleared to zero. If there are two interfaces, such as an ATA Primary and
Secondary interface, the primary interface shall be zero, and the secondary
interface shall be one.
Values 00h through FEh shall represent a valid Channel Number.
FFh shall indicate that this field is not used.
If the device is connected to a SATA controller functioning in non-PATA
emulation mode, this byte shall be FFh.
52 DWord Reserved