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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262-004US
701
Expansion Bus Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network
Processors
50Kohm that are only enabled when PLL_LOCK is deasserted. Pull-down resistors may
be placed on some of the 25 address lines in order to select the configuration values at
reset. The pull-down resistors must be able to over-drive the internal pull-up resistors.
Please refer to
Section 12.5.9, “Configuration Register 0” on page 706
for additional
details on particular configuration options. The Expansion bus controller samples
EX_ADDR when reset_early_n = ‘0’, which occurs during power up or during a watch
dog reset. However, the Expansion bus controller only samples the Intel XScale
processor Clock Set bits, EX_ADDR[23:21], when reset_early_n = ‘0’ and reset_cold_n
= ‘0’.
12.4.8.1
Sampling EX_ADDR During Reset
12.4.8.2
Expansion Bus Controller Operation
In this document, there are several occurrences of the word “must” in the description
of the functional operation of the Expansion Bus Controller. Failure to comply to these
requirements will result in unpredictable behavior of the Expansion Bus Controller.
12.5
Detailed Register Descriptions
Accesses to Expansion bus registers is only word transfers. Byte and half-word
accesses result in unpredictable operation. Accesses to all reserved bits must be
written with zero unless otherwise specified. All reserved address spaces must not be
read. All writes to reserved address spaces results in unpredictable operation. External
master sub-word accesses to the EXP_INBOUND_ADDR and EXP_LOCK[1:0] registers
will be treated as a word access.
Figure 164. Sampling EX_ADDR During Reset
B4463-01
OSC_IN
- 0 -
- 1 -
- 2 -
- 3 -
- 4 -
- 5 -
- 6 -
- 7 -
- 8 -
- 9 -
RESET_IN_N
RESET_ EARLY_N
RESET_ COLD_N
RESET_N
PLL_ LOCKED
EX_ ADDR
STATE
- 10 -
CAPTURE
INPUT
OUTPUT
EX_ ADDR
STOP CAPTURING EX
_ ADDR
DRIVE EX_ ADDR
Table 225.
Register Legend
Attribute
Legend
Attribute
Legend
RV
Reserved
RC
Read Clear
PR
Preserved
RO
Read Only