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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Expansion Bus
Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
714
Order Number: 306262-004US
The EXP_UNIT_FUSE_RESET register can be read by software to determine which
features are fused out or being software disabled. Software can choose to disable
features for blocks that are not being used to lower power consumption by writing a ‘1’
to the appropriate bit for the feature that needs to be disabled. Disabling features by
software is recommended to be done during the system initialization phase (i.e. before
the start or use of the related feature to be disabled). A feature cannot be enabled after
being disabled without asserting system reset. Any block can be independently disabled
by software, however the HDLC and HSS must always be both enabled or both disabled
by software since these blocks work together. For blocks that have external pin
interfaces, pull-ups or pull-downs are enabled in the PAD I/O, and these pins should be
left unconnected in the system.
Each of the NPE’s can also be reset anytime through software by writing a ‘1’ to the
appropriate NPE bit (NPE-A, NPE-B, or NPE-C) in the EXP_UNIT_FUSE_RESET register.
When a NPE is reset, all the coprocessors that belong to that NPE are also automatically
reset and all the coprocessor data transfers to external interfaces are terminated
immediately. When resetting the NPE’s, software should do a read modify write to the
EXP_UNIT_FUSE_RESET register and only set the NPE bit that needs to be reset. A read
modify write must ensure that the NPE coprocessors that were previously disabled
continue to be disabled and the coprocessors that are enabled continue to be enabled.
Writing a ‘1’ to a NPE coprocessor bit that is already enabled when resetting the NPE’s
will disable that coprocessor and cause the coprocessor interface pins to enter an
unknown state. When software writes a ‘1’ to reset a NPE, the EXP_UNIT_FUSE_RESET
register will not reflect the reset status until that NPE has been reset. Typically software
will poll the EXP_UNIT_FUSE_RESET register until that NPE bit that is being reset
10
NPE-C
ETHERNET
0 = NPE-C Ethernet Enabled
1 = NPE-C Ethernet Disabled
FUSE[18]
RW
9
NPE-B
ETHERNET 0
0 = NPE-B Ethernet 0 Enabled
1 = NPE-B Ethernet 0 Disabled
Refer to
for more details.
FUSE[17]
RW
8
UTOPIA
0 = UTOPIA Enabled
1 = UTOPIA Disabled/NPE-A ethernet enabled if NPE-A ETHERNET=0
Refer to
for more details.
FUSE[16]
RW
7
HSS
0 = HSS Enabled
1 = HSS Disabled and clock gated
FUSE[13]
RW
6
Reserved
Reserved
FUSE[14]
RW
5
HDLC
0 = HDLC Enabled
1 = HDLC Disabled and clock gated
FUSE[13]
RW
4
DES
0 = DES Enabled
1 = DES Disabled
FUSE[10]
RW
3
AES
0 = AES Enabled
1 = AES Disabled
FUSE[10]
RW
2
Hashing Cop
0 = HASH Enabled
1 = HASH Disabled
FUSE[10]
RW
1
USB Device
0 = USB DEVICE Enabled
1 = USB DEVICE Disabled and clock gated
FUSE[9]
RW
0
PCI RCOMP
0 = PCI RCOMP Enabled
1 = PCI RCOMP Disabled
This bit must be set to a ‘1’ if the PCI interface is not being used and
SMII mode is enabled.
0 RW
Register
EXP_UNIT_FUSE_RESET
Bits
Name
Description
Reset
Value
Access