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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors—Memory Controller
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Developer’s Manual
August 2006
646
Order Number: 306262-004US
not defined for programming. In this case the two ports are both set to High priority,
but with only two agents at high, and no winner from the Medium priority level, the
preemption control will work as expected.
Note:
Preemption is not supported on the IXP45X/IXP46X network processors, therefore this
register must remain set at its default value.
11.6.14
Refresh Frequency Register RFR
The Refresh Frequency Register is programmed for refreshing the DD1R SDRAM
subsystem at the specified interval. Writing to the RFR programs the refresh counter
with the Refresh Interval. Reading from the RFR results in the value currently within the
refresh counter. Refer to
“Typical Refresh Frequency Register Values” on page 614
for
recommended programmed values.
Register Name:
MCU Preemption Control Register - MPCR
Hex Offset Address:
CC00 E540H
Reset Hex Value:
0x0000 0000H
Register Description:
MCU Preemption Control Register
Access: See below.
31
04 03
00
(Reserved)
(Reserved)
Register
MCU Preemption Control Register - MPCR
Bits
Name
Description
Default
Access
31:0
4
(Reserved)
0
RO
03:0
0
(Reserved)
Preemption Data Phase Count: Specifies the number of DDRI data
bursts that will complete before the current transactions will be
preempted. The count is based from the beginning of the transaction.
When a core transaction port request is detected after the count has
been exceeded by the current transaction, the transaction will be
preempted at the next burst length boundary. The current transaction
must be a non-Core transaction.
0H = Disabled
All other values are reserved.
0H
RW
Register Name:
Refresh Frequency Register - RFR
Hex Offset Address:
CC00 E548H
Reset Hex Value:
0x0000 0000H
Register Description:
Refresh Frequency Register
Access: See below.
31
12 11
00
(Reserved)