Specification Sheet

Datasheet, Volume 2 of 2 399
PCI Express* Controller (x16) Registers
12.45 Root Status (RSTS)—Offset C0h
Provides information about PCI Express Root Complex specific parameters.
Access Method
Default: 0h
12.46 Device Capabilities 2 (DCAP2)—Offset C4h
Access Method
Default: B80h
Type: CFG
(Size: 32 bits)
Offset: [B:0, D:1, F:0] + C0h
3
1
2
8
2
4
2
0
1
6
1
2
8 4 0
0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
RSVD
PMEP
PMES
PMERID
Bit
Range
Default &
Access
Field Name (ID): Description
31:18
0h
RO
Reserved (RSVD): Reserved.
17
0h
RO
PMEP: PME Pending: Indicates that another PME is pending when the PME Status bit is
set. When the PME Status bit is cleared by software; the PME is delivered by hardware
by setting the PME Status bit again and updating the Requestor ID appropriately. The
PME pending bit is cleared by hardware if no more PMEs are pending.
16
0h
RW1C
PMES: PME Status: Indicates that PME was asserted by the requestor ID indicated in
the PME Requestor ID field. Subsequent PMEs are kept pending until the status
register is cleared by writing a 1 to this field.
An interrupt is asserted If PMEIE is asserted and PMES is changing from 0 to 1
An interrupt is de-asserted If PMEIE is asserted and PMES is changing from 1 to 0
An Assert_PMEGPE is sent upstream If PMEGPEE in PEG Legacy cControl register
(PEGLC) is asserted and PMES is changing from 0 to 1 An Deassert_PMEGPE is sent
upstream If PMEGPEE in PEG Legacy cControl register (PEGLC) is asserted and PMES is
changing from 1 to 0
An interrupt is de-asserted If PMEIE is asserted and PMES is changing from 1 to 0
15:0
0h
ROV
PMERID: PME Requestor ID: Indicates the PCI requestor ID of the last PME requestor.
Type: CFG
(Size: 32 bits)
Offset: [B:0, D:1, F:0] + C4h