Expansion Interface; Supported Ddri Memory Configurations - Intel IXP45X Developer's Manual

Intel
Table 3 on page 54
IXP45X/IXP46X network processors. The 128/256/512-Mbit, 1-Gbit DDRI SDRAM
devices comprise four internal leaves. The MCU controls the leaf selects within 128/
256/512-Mbit, 1-Gbit DDRI SDRAM by toggling DDRI_BA[0] and DDRI_BA[1].
The two DDRI SDRAM chip enables DDRI_CS_N[1:0] support a DDRI SDRAM memory
subsystem consisting of two banks. The base address for the two contiguous banks are
programmed in the DDRI SDRAM Base Register (SDBR) and must be aligned to a 32-
Mbyte boundary. The size of each DDRI SDRAM bank is programmed with the DDRI
SDRAM boundary registers (SBR0 and SBR1).
Table 3.

Supported DDRI Memory Configurations

DDRI SDRAM
Technology
128 Mbit
256 Mbit
512 Mbit
1 Gbit
Notes:
1. Table indicates 32-bit-wide memory subsystem sizes
The memory controller is a 32-bit only interface. If a x16 memory chip is used, a
minimum of two memory chips would be required to facilitate the 32-bit interface
required by the IXP45X/IXP46X network processors. If ECC is required, additional
memories would need to be added. For more information on DDRI SDRAM support and
configuration see the Memory Controller section contained later in this document.
The memory controller internally interfaces to the North AHB, South AHB, and Memory
Port Interface with independent interfaces. This architecture allows DDRI SDRAM
transfers to be interleaved and pipelined to achieve maximum possible efficiency.
2.1.8

Expansion Interface

The expansion interface allows easy and — in most cases — glue-less connection to
peripheral devices. It also provides input information for device configuration after
reset.
® ®
Intel IXP45X and Intel IXP46X Product Line of Network Processors
Developer's Manual
54
® ®
IXP45X and Intel IXP46X Product Line of Network Processors—Functional Overview
illustrates the supported DDRI SDRAM configurations for the
DDRI SDRAM
# Banks
Arrangement
1
16M x 8
2
1
8M x 16
2
1
32M x 8
2
1
16M x 16
2
1
64M x 8
2
1
32M x 16
2
1
128M x 8
2
1
64M x 16
2
Address Size Leaf Select
Row Col DDRI_BA[1]
12 10 I_AD[26]
12 9 I_AD[25]
13 10 I_AD[27]
13 9 I_AD[26]
13 11 I_AD[28]
13 10 I_AD[27]
14 11 I_AD[29]
14 10 I_AD[28]
Total
Memory
1
Size
DDRI_BA[0]
64 Mbyte
I_AD[25]
128 Mbyte
32 Mbyte
I_AD[24]
64 Mbyte
128 Mbyte
I_AD[26]
256 Mbyte
64 Mbyte
I_AD[25]
128 Mbyte
256 Mbyte
I_AD[27]
512 Mbyte
128 Mbyte
I_AD[26]
256 Mbyte
512 Mbyte
I_AD[28]
1 Gbyte
256 Mbyte
I_AD[27]
512 Mbyte
August 2006
Reference Number: 306262-004US