
IBM21P100BGB
IBM 133 PCI-X Bridge R1.1
ppb11_pcix_regs.fm.03
July 9, 2001
Configuration Registers
Page 51 of 131
5.2.4.25 I/O Base Upper 16 Bits Register
The I/O Base Upper 16 Bits 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.
5.2.4.26 I/O Limit Upper 16 Bits Register
The I/O Limit Upper 16 Bits 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‘XXXX’
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
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.
Address Offset
x‘32’
Access
See individual fields
Reset Value
x‘XXXX’
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.