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Intel
®
IXP43X Product Line of Network Processors
April 2007 HDG
Document Number: 316844; Revision: 001US 75
Hardware Design Guidelines—Intel
®
IXP43X Product Line of Network Processors
The DDR_RCOMP signal must be terminated through resistors specified in Figure 26.
This allows the DDRII/I controller to make temperature and process adjustments.
7.2 DDRII/DDRI RCOMP and Slew Resistances Pin
Requirements
Figure 26 shows the requirements for the DDRII/DDRI RCOMP pin.
For example, when DDRI SDRAM is used, DDRIMPCRES is connected with 387Ω and
DDRSLWCRES is connected with 845Ω resistor to DDRCRES0.
Table 28. Supported DDRII 16-bit SDRAM Configurations
DDR SDRAM
Technology
DDR SDRAM
Arrangement
# of
Banks
Address Size Leaf Select
Total
Memory
Size
Page
Size
Row Column
DDR_BA[1
]
DDR_BA[0]
256 Mbit 16M x16 1 13 9 ADDR[24] ADDR[23] 32MB 1KB
Figure 26. DDRII/DDRI RCOMP Pin External Resistor Requirements
Intel® IXP43X
Product Line of
Network Processors
DDRIMPCRES
DDRSLWCRES
DDRCRES
0
DDRI
R1 = 38 7Ω
± 1
%
resistor
OR
DDRII
R1 = 285Ω
± 1
% resistor
R1
R2
DDRI
R2 = 84 5Ω
± 1
% resistor
OR
DDRII
R2 = 825Ω
± 1
% resistor