Intel
®
81341 and 81342 I/O Processors
December 2007
Developer’s Manual
Order Number: 315037-002US
231
Address Translation Unit (PCI-X)—Intel
®
81341 and 81342
2.13.88 PCIX RCOMP Control Register — PRCR
Warning:
In Central Resource mode this register can only be accessed when PCSR bit 21 is
cleared. Refer to
Table 64, “PCI Configuration and Status Register - PCSR” on
Table 111. PCIX RCOMP Control Register - PRCR
Bit
Default
Description
31:12
00000H
Reserved
11
0
2
When this bit is set, the slew rate manual override values are used. When this bit is cleared, the slew
rate is derived from the drive strength (normal operation).
10:09
00
2
Reference select for PCIX CAP pad
2'b00 Nominal Reference Voltage
2'b01 -5% Reference
2'b10 +5% Reference
08:07
01
2
Drive strength select for ODT RCOMP pad
2'b00 103.0 ohms
2'b01 110.0 ohms
2'b10 120.0 ohms
06:04
010
2
Drive strength select for RCOMP pad dedicated 3.3V supply voltage
3'b000 18.0 ohms
3'b001 20.1 ohms
3'b010 22.0 ohms
3'b011 24.1 ohms
3'b100 26.1 ohms
03:01
001
2
Drive strength select for RCOMP pad 1.5V switch supply voltage
3'b000 18.0 ohms
3'b001 20.1 ohms
3'b010 22.0 ohms
3'b011 24.1 ohms
3'b100 26.1 ohms
00
1
2
RCOMP pads enable.
PCI
IOP
Attributes
Attributes
28
24
20
16
12
8
4
0
31
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rv
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
rw
na
Attribute Legend:
RV = Reserved
PR = Preserved
RS = Read/Set
RW = Read/Write
RC = Read Clear
RO = Read Only
NA = Not Accessible
Intel XScale
®
processor Local Bus
offset
+2100H