
IBM21P100BGC
IBM 133 PCI-X Bridge R2.0
Configuration Registers
ppb20_pcix_regs.fm.01
October 15, 2001
5.2.4.26 I/O Base Upper 16 Bits Register
This register specifies the base of the I/O address range bits 31:16 and is used in conjunction with the I/O
base register, the I/O limit register, and I/O limit upper 16 bits register to specify a range of 32-bit addresses
supported for I/O transactions on the PCI bus. Address bits 11:0 are assumed to be x‘000’ for the base
address.
5.2.4.27 I/O Limit Upper 16 Bits Register
This register specifies the upper address of the I/O address range bits 31:16 and is used in conjunction with
the I/O base register, I/O limit register and I/O base upper 16 bits register to specify a range of 32-bit
addresses supported for I/O transactions on the PCI bus. Address bits 11:0 are assumed to be x‘FFF’ for the
limit address.
Address Offset
x‘30’
Access
See individual fields
Reset Value
x‘0000’
I/O Base Upper 16 Bits
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Bit(s)
Access
FieldNameand Description
15:0
RW
Address bits 31:16 of the base address for the address range of I/O operations that are passed from the pri-
mary to the secondary PCI bus.
Address Offset
x‘32’
Access
See individual fields
Reset Value
x‘0000’
I/O Limit Upper 16 Bits
15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Bit(s)
Access
Field Name and Description
15:0
RW
Address bits 31:16 of the base address for the address range of I/O operations that are passed from the pri-
mary to the secondary PCI bus.