Field Name Bits Default Description
Reserved 2:0 Reserved
Interrupt Status 3 0b This bit reflects the state of the interrupt in the
device/function. Only when the Interrupt Disable bit in the
command register is a 0 and this Interrupt Status bit is a 1,
will the device’s/function’s INTx# signal be asserted. Setting
the Interrupt Disable bit to a 1 has no effect on the state of
this bit.
Capabilities List 4 1b A value of 0 indicates that no New Capabilities linked list is
available.
A value of 1 indicates that the value read at offset 34h is a
pointer in Configuration Space to a linked list of new
capabilities.
66 MHz Capable 5 1b Hard-wired to 1, indicating 66MHz capable.
Reserved 6 Reserved
Fast Back-to-Back
Capable
7 1b Hard-wired to 1, indic ating Fast Back-to-Back capable.
Master Data Parity Error 8 0b This bit is set only when three conditions are met: 1) the bus
agent asserted PERR# itself (on a read) or observed PERR#
asserted (on a write); 2) the agent setting the bit acted as the
bus master for the operation in which the error occurred; and
3) the Parity Error Response bit (Command register) is set.
DEVSEL timing 10:9 01b Hard-wired to 01b – medium timing
Signaled Target Abort 11 0b This bit is set by a target device whenever it terminates a
transaction with Target-Abort.
Received Target Abort 12 0b This bit is set by a master device whenever its transaction is
terminated with Target-Abort.
Received Master Abort 13 0b This bit is set by a master device whenever its transaction
(except for Special Cycle) is terminated with Master-Abort.
Signaled System Error 14 0b This bit is set whenever the device asserts SERR#.
Detected Parity Error 15 0b This bit is set by the device whenever it detects a parity error,
even if parity error handling is disabled (as controlled by bit 6
in the Command register).
Revision ID / Class Code – R - 32 bits - [PCI_Reg : 08h] Field Name Bits Default Description
Revision ID 7:0 00h Revision ID.
PI 15:8 20h Programming Interface. A constant value of ‘20h’ indentifies
the device being an EHCI Host Controller.
SC 23:16 03h Sub Class. A constant value of ‘03h’ indentifies the device
being of Universal Serial Bus.
BC 31:24 0Ch Base Class. A constant value of ‘0Ch’ identifies the device
being a Serial Bus Controller.
Field Name Bits Default Description
Cache Line Size 7:0 00h This read/write field specifies the system cacheline size in
units of DWORDs and must be initialized to 00h.
Latency Timer 15:8 00h [9:8] hard-wired to 00b, resulting in a timer granularit y of at
least four clocks. This field specifies, in units of PCI bus
clocks, the value of the Latency Timer for this PCI bus
master.