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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262-004US
645
Memory Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
11.6.12
MCU Port Transaction Count Register MPTCR
Sets the number of transactions a given port can have processed during a single
tenure. The 4-bit fields for each port allow up to 16 transactions to be processed by a
port before the MCU arbiter selects a different port for DDRI SDRAM transactions. This
register along with the
“MCU Port Transaction Count Register MPTCR” on page 645
and
“MCU Preemption Control Register MPCR” on page 645
controller operation.
Note:
For the
IXP45X/IXP46X network processors, this value MUST remain programmed to
11H in order to prevent unfair arbitration and indeterminate results.
11.6.13
MCU Preemption Control Register MPCR
Enables Preemption of IB port transaction when a core processor transaction is
pending.
The CMTQ must be the only memory transaction queue set to “High” (00
2
) priority in
the MACR, if preemption is to be enabled. If preemption is enabled when CMTQ priority
is set to anything other than High, or additional ports are set to High, indeterminate
results may occur. A special case is where there are only two ports, and the MACR is
Register Name:
MCU Port Transaction Count Register - MPTCR
Hex Offset Address:
CC00 E53CH
Reset Hex Value:
0x0000 0011H
Register Description:
MCU Port Transaction Count Register
Access: See below.
31
08 07
04 03
00
(Reserved)
Register
MCU Port Transaction Count Register - MPTCR
Bits
Name
Description
Default
Access
31:0
8
(Reserved)
000000H
RO
07:0
4
North and South AHB Transaction Count: Number of transactions the
IB MCU port can have processed in a single tenure of the DDRI
SDRAM.
1H = 1 transaction
2H = 2 transaction
3H = 3 transaction
...
FH = 15 transactions
0H = 16 transactions
0001
2
RW
03:0
0
Core Transaction Count: Number of transactions the Core processor
MCU port can have processed in a single tenure of the DDRI SDRAM.
1H = 1 transaction
...
FH = 15 transactions
0H = 16 transactions
0001
2
RW