Intel BX80605I7870 Data Sheet - Page 39

PCICMD - Command Register

Page 39 highlights

Register Description 2.5.7 PCICMD - Command Register This register defines the PCI 3.0 compatible command register values applicable to PCI Express space. Device: Function: Offset: 0 0-1 04h Device: Function: Offset: 2 0-1, 4-5 04h Device: Function: Offset: 3 0-2, 4 04h Device: Function: Offset: 4-6 0-3 04h Bit 15:11 10 9 8 7 6 5 4 3 2 1 0 Type RV RO RO RO RO RO RO RO RO RO RO RO Reset Value 0 0 0 0 0 0 0 0 0 1 1 0 Description Reserved. (by PCI SIG) INTxDisable: Interrupt Disable Controls the ability of the PCI Express port to generate INTx messages. If this device does not generate interrupts then this bit is not implemented and is RO. If this device generates interrupts then this bit is RW and this bit disables the device/function from asserting INTx#. A value of 0 enables the assertion of its INTx# signal. A value of 1 disables the assertion of its INTx# signal. 1 = Legacy Interrupt mode is disabled 0 = Legacy Interrupt mode is enabled FB2B: Fast Back-to-Back Enable This bit controls whether or not the master can do fast back-to-back writes. Since this device is strictly a target this bit is not implemented. This bit is hardwired to 0. Writes to this bit position have no effect. SERRE: SERR Message Enable This bit is a global enable bit for this devices SERR messaging. This host bridge will not implement SERR messaging. This bit is hardwired to 0. If SERR is used for error generation, then this bit must be RW and enable/disable SERR signaling. IDSELWCC: IDSEL Stepping/Wait Cycle Control Per PCI 2.3 specification this bit is hardwired to 0. PERRE: Parity Error Response Enable Parity error is not implemented in this host bridge. This bit is hardwired to 0. VGAPSE: VGA palette snoop Enable This host bridge does not implement this bit. This bit is hardwired to 0. MWIEN: Memory Write and Invalidate Enable This host bridge will never issue memory write and invalidate commands. This bit is therefore hardwired to 0. SCE: Special Cycle Enable This host bridge does not implement this bit. This bit is hardwired to a 0. BME: Bus Master Enable This host bridge is always enabled as a master. This bit is hardwired to a 1. MSE: Memory Space Enable This host bridge always allows access to main memory. This bit is not implemented and is hardwired to 1. IOAE: Access Enable This bit is not implemented in this host bridge and is hardwired to 0. Datasheet 39

  • 1
  • 2
  • 3
  • 4
  • 5
  • 6
  • 7
  • 8
  • 9
  • 10
  • 11
  • 12
  • 13
  • 14
  • 15
  • 16
  • 17
  • 18
  • 19
  • 20
  • 21
  • 22
  • 23
  • 24
  • 25
  • 26
  • 27
  • 28
  • 29
  • 30
  • 31
  • 32
  • 33
  • 34
  • 35
  • 36
  • 37
  • 38
  • 39
  • 40
  • 41
  • 42
  • 43
  • 44
  • 45
  • 46
  • 47
  • 48
  • 49
  • 50
  • 51
  • 52
  • 53
  • 54
  • 55
  • 56
  • 57
  • 58
  • 59
  • 60
  • 61
  • 62
  • 63
  • 64
  • 65
  • 66
  • 67
  • 68
  • 69
  • 70
  • 71
  • 72
  • 73
  • 74
  • 75
  • 76
  • 77
  • 78
  • 79
  • 80
  • 81
  • 82
  • 83
  • 84
  • 85
  • 86
  • 87
  • 88
  • 89
  • 90
  • 91
  • 92
  • 93
  • 94
  • 95
  • 96
  • 97
  • 98

Datasheet
39
Register Description
2.5.7
PCICMD - Command Register
This register defines the PCI 3.0 compatible command register values applicable to PCI
Express space.
Device:
0
Function:
0-1
Offset:
04h
Device:
2
Function:
0-1, 4-5
Offset:
04h
Device:
3
Function:
0-2, 4
Offset:
04h
Device:
4-6
Function:
0-3
Offset:
04h
Bit
Type
Reset
Value
Description
15:11
RV
0
Reserved. (by PCI SIG)
10
RO
0
INTxDisable: Interrupt Disable
Controls the ability of the PCI Express port to generate INTx messages.
If this device does not generate interrupts then this bit is not implemented and
is RO.
If this device generates interrupts then this bit is RW and
this bit disables the
device/function from asserting INTx#. A value of 0 enables the assertion of its
INTx# signal. A value of 1 disables the assertion of its INTx# signal.
1 =
Legacy Interrupt mode is disabled
0 =
Legacy Interrupt mode is enabled
9
RO
0
FB2B: Fast Back-to-Back Enable
This bit controls whether or not the master can do fast back-to-back writes.
Since this device is strictly a target this bit is not implemented. This bit is
hardwired to 0. Writes to this bit position have no effect.
8
RO
0
SERRE: SERR Message Enable
This bit is a global enable bit for this devices SERR messaging. This host bridge
will not implement SERR messaging. This bit is hardwired to 0. If SERR is used
for error generation, then this bit must be RW and enable/disable SERR
signaling.
7
RO
0
IDSELWCC: IDSEL Stepping/Wait Cycle Control
Per PCI 2.3 specification this bit is hardwired to 0.
6
RO
0
PERRE: Parity Error Response Enable
Parity error is not implemented in this host bridge. This bit is hardwired to 0.
5
RO
0
VGAPSE: VGA palette snoop Enable
This host bridge does not implement this bit. This bit is hardwired to 0.
4
RO
0
MWIEN: Memory Write and Invalidate Enable
This host bridge will never issue memory write and invalidate commands. This
bit is therefore hardwired to 0.
3
RO
0
SCE: Special Cycle Enable
This host bridge does not implement this bit. This bit is hardwired to a 0.
2
RO
1
BME: Bus Master Enable
This host bridge is always enabled as a master. This bit is hardwired to a 1.
1
RO
1
MSE: Memory Space Enable
This host bridge always allows access to main memory. This bit is not
implemented and is hardwired to 1.
0
RO
0
IOAE: Access Enable
This bit is not implemented in this host bridge and is hardwired to 0.