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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
588
Order Number: 306262-004US
The MCU supports only a 32-bit data bus width memory implementation (with and
without ECC). The data bus width is controlled by the DDRI SDRAM Control Register.
The MCU supports DDRI SDRAM burst length of four. A burst length of four enables
seamless read/write bursting of long data streams as long as the memory transaction
does not cross the page boundary. Page boundaries are at naturally aligned boundaries.
The MCU ensures that the page boundary is not crossed within a single transaction by
initiating a disconnect at next ADB (128-byte address boundary) on the internal bus
prior to the page boundary.
11.2.2.1
DDRI SDRAM Interface
The DDRI SDRAM interface signals generated by the memory controller unit are for
DDRI SDRAM operation, there are no signals supporting DDRII SDRAM. Refer to the
Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors Datasheet for
specifics on DDRI SDRAM interface signals.
The MCU SDRAM interface provides a flexible mix of combinations including:
illustrates how two banks of DDRI SDRAM would interface with the IXP45X/
IXP46X network processors through the MCU.
Table 202.
DDRI SDRAM Memory Configuration Options
Data Bus Width
ECC Enabled
Maximum Throughput(1)
32 bit
Yes
1066 Mbyte/s
32 bit
No
1066 Mbyte/s
Note:
1.
Based on DDRI 266 MHz SDRAM