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IBM3206K0424
Preliminary
IBM Processor for Network Resources
pnr25.chapt04.01
August 14, 2000
The IOP Bus Specific Interface Controller (PCINT)
Page 99 of 676
1.5: PCINT Base Address 1 (I/O for Register)
This register specifies the base address of where in PCI I/O or memory space the IBM3206K0424 registers
will be mapped. When written with
’
1
’
s and read back, the least significant bits read back as
’
0
’
will indicate
the amount of I/O space required for this device to operate. For example, when a value of
’
FFFFFFFF
’
is writ-
ten, a value read of
’
FFFFFF00
’
indicates that 256 bytes of address space is required. See bit definitions.
The programming of this bit depends on whether the IBM3206K0424 is in 64-bit addressing mode or not.
When in 64-bit addressing mode, bit 4 of the PCINT 64-bit Controller Register is set to
’
1
’
, and this register
specifies a memory address. When the IBM3206K0424 is not in 64-bit addressing mode because bit 4 of the
PCINT 64-bit Control Register is set to
’
0
’
, this register specifies an I/O address. See bit definitions and
PCINT 64-bit Control Register
on page 116.
When in 64-bit Addressing Mode (that is, bit 64 of PCINT 64-bit Control Register is set to ’1’):
Length
32 bits
Type
Read/Write
Address
XXXX 0010
Restrictions
Can be written or read during configuration cycle, memory cycle when enabled (see
PCINT Base Address Control Register on page 111
), or an I/O cycle. This register
is documented as big endian, but how data is presented on the PCI bus depends
on how the controls are set in the PCINT Endian Control Register. Bit 17 in the
PCINT Base Address Control Register must be set to allow the IBM3206K0424 to
decode addresses for this range.
Power on Reset value
(Big Endian)
X
’
00000001
’
Power on Reset value
(Little Endian)
X
’
01000000
’
Base Address
P
M
31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10
9
8
7
6
5
4
3
2
1
0
Bit(s)
PCI Spec
Name
Description
31-4
31-4
Base Address
This register is used to hold the address where the target device will
decode for memory accesses. The size is 32K of addressing, naturally
aligned. This means that only bits 31-15 are writable.
3
3
Prefetchable
Reserved and set to
‘
0
’
.
2-1
2-1
This base address can be mapped anywhere in 32-bit address space. The
value of these bits is 00b.
0
0
Memory space
This is memory space, so the bit is set to
’
0
’
.