82801FB Datasheet, PDF (333/786 Pages) Intel Corporation – Intel I/O Controller Hub 6 (ICH6) Family

PCI-to-PCI Bridge Registers (D30:F0)
9.1.13
9.1.14
MEMBASE_LIMIT—Memory Base and Limit Register
(PCI-PCI—D30:F0)
Offset Address: 20–23h
Default Value: 00000000h
Attribute:
Size:
R/W, RO
32 bits
This register defines the base and limit, aligned to a 1-MB boundary, of the non-prefetchable
memory area of the bridge. Accesses that are within the ranges specified in this register will be sent
to PCI if CMD.MSE is set. Accesses from PCI that are outside the ranges specified will be
accepted by the bridge if CMD.BME is set.
Bit
Description
31-20
19-16
15:4
3:0
Memory Limit (ML) — R/W. These bits are compared with bits 31:20 of the incoming address to
determine the upper 1-MB aligned value (exclusive) of the range. The incoming address must be
less than this value.
Reserved
Memory Base (MB) — R/W. These bits are compared with bits 31:20 of the incoming address to
determine the lower 1-MB aligned value (inclusive) of the range. The incoming address must be
greater than or equal to this value.
Reserved
PREF_MEM_BASE_LIMIT—Prefetchable Memory Base
and Limit Register (PCI-PCI—D30:F0)
Offset Address: 24–27h
Default Value: 00010001h
Attribute:
Size:
R/W, RO
32-bit
Defines the base and limit, aligned to a 1-MB boundary, of the prefetchable memory area of the
bridge. Accesses that are within the ranges specified in this register will be sent to PCI if
CMD.MSE is set. Accesses from PCI that are outside the ranges specified will be accepted by the
bridge if CMD.BME is set.
Bit
Description
31-20
19-16
15:4
3:0
Prefetchable Memory Limit (PML) — R/W. These bits are compared with bits 31:20 of the
incoming address to determine the upper 1-MB aligned value (exclusive) of the range. The incoming
address must be less than this value.
64-bit Indicator (I64L) — RO. This field indicates support for 64-bit addressing.
Prefetchable Memory Base (PMB) — R/W. These bits are compared with bits 31:20 of the
incoming address to determine the lower 1-MB aligned value (inclusive) of the range. The incoming
address must be greater than or equal to this value.
64-bit Indicator (I64B) — RO. This field indicates support for 64-bit addressing.
Intel^® I/O Controller Hub 6 (ICH6) Family Datasheet
333