
IBM32NPCXX1EPABBE66
IBM Processor for Network Resources
Preliminary
The IOP Bus Specific Interface Controller (PCINT)
Page 52 of 706
pnr261_3pcint.fm.06
August 14, 2000
20
Disable Retrying on the 1st Cycle
of a Memory Access
Setting this bit to
‘
1
’
disables the retrying of a memory access to PNR. This causes a PCI
spec violation, but not a data integrity problem. It solves the rare problem in which two
masters are accessing Control Memory at the same time and retries happen to both end-
lessly.
19
Enable Writing to Special Config
Registers
Setting this bit to
‘
1
’
enables writing to certain registers that are normally read-only. An
example of this is the vendor and function ID register (PCINT Configuration Word 0).
18
Disable Incremental Latency
Time-out Retries
Setting this bit to
‘
1
’
disables PCI retries due to cycles taking more than eight cycles on
burst accesses after the first access.
17
Enable PCINT Base Address 1
(I/O for regs)
Setting this bit to
‘
1
’
enables PCINT Base Address 1 (I/O for registers). This does the
same function as bit 0 in the PCINT Configuration Word 1 register, but also makes the
PCINT Base Address 1 (I/O for regs) read back
‘
0
’
s even when written to with values. It
guards against anything that BIOS code may do to PCINT Configuration Word 1 register
bit 0 if I/O accesses are not desired.
16
Enable PCINT Base Address 2
(Mem for regs)
Setting this bit to
‘
1
’
enables PCINT Base Address 2 (Mem for regs) so PNR registers can
be accessed by PCI memory cycles.
15-12
Encoded Control for PCINT Base
Address 6 (Memory)
Same as bits 3-0.
11-8
Encoded Control for PCINT Base
Address 5 (Memory)
7-4
Encoded Control for PCINT Base
Address 4 (Memory)
3-0
Encoded Control for PCINT Base
Address 3 (Memory)
Encoding of bits:
x
‘
0
’
x
‘
1
’
x
‘
2
’
x
‘
3
’
x
‘
4
’
x
‘
5
’
x
‘
6
’
x
‘
7
’
x
‘
8
’
x
‘
9
’
x
‘
A
’
x
‘
B
’
x
‘
C
’
x
‘
D
’
Disable this Base Address.
Configured to respond to a 2 GB address size.
Configured to respond to a 1 GB address size.
Configured to respond to a 512 MB address size.
Configured to respond to a 256 MB address size.
Configured to respond to a 128 MB address size.
Configured to respond to a 64 MB address size.
Configured to respond to a 32 MB address size.
Configured to respond to a 16 MB address size.
Configured to respond to a 8 MB address size.
Configured to respond to a 4 MB address size.
Configured to respond to a 2 MB address size.
Configured to respond to a 1 MB address size.
Configured to respond to a 64-KB address size, and enables internal windowing
of memory.
Configured to respond to a 32-KB address size, and enables internal windowing
of memory.
Configured to respond to a 16-KB address size, and enables internal window.
x
‘
E
’
x
‘
F
’
Bit(s)
Name
Description