Datasheet
PCI Express Extended Configuration Space
96
March 5 2007 − June 2011SCPS154C
5.22 VC Resource Control Register (VC0)
The VC resource control register for VC0 allows software to control VC0 and the associated port and
arbitration schemes supported by the bridge. See Table 5−18 for a complete description of the register
contents.
PCI Express extended register offset: 164h
Register type: Read-only, Read/Write
Default value: 8000 00FFh
BIT NUMBER 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
RESET STATE 1 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0
BIT NUMBER 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
RESET STATE 0 0 0 0 0 0 0 0 1 1 1 1 1 1 1 1
Table 5−18. VC Resource Control Register (VC0) Description
BIT FIELD NAME ACCESS DESCRIPTION
31 VC_EN R
VC enable. This field is internally hardwired to 1b to indicate that this VC resource is always
enabled.
30:27 RSVD R Reserved. Returns 0h when read.
26:24 VC_ID R
Virtual channel ID. This field is internally hardwired to 000b to indicate that this VC resource
is always used for VC0.
23:20 RSVD R Reserved. Returns 0h when read.
19:17 PORT_ARB_SELECT R
Port arbitration select. This read-only field returns 000b when read, because only
hardware-fixed, round-robin arbitration is supported for this VC.
16 LOAD_PORT_TABLE R
Load port arbitration table. This read-only bit returns 0b when read, because no port
arbitration table is supported for this VC.
15:8 RSVD R Reserved. Returns 00h when read.
7:0 TC_VC_MAP RW
TC/VC map. This field indicates all of the traffic classes that are mapped to this VC. A 1b in
any bit position indicates that the corresponding traffic class is enabled for this VC. A 0b
indicates that the corresponding traffic class is mapped to a different VC. The following table
is used:
Bit 0 = Traffic class 0 (This bit is read-only and returns a value of 1b)
Bit 1 = Traffic class 1
Bit 2 = Traffic class 2
Bit 3 = Traffic class 3
Bit 4 = Traffic class 4
Bit 5 = Traffic class 5
Bit 6 = Traffic class 6
Bit 7 = Traffic class 7
The default value of FFh indicates that all eight traffic classes are initially mapped to VC0.
Not Recommended for New Designs