Intel IXP45X, IXP46X manual Introduction, DDR Signal Groups, DDRIDQS40, DDRICKE10

DDR-SDRAM—Intel®IXP45X and Intel® IXP46X Product Line of Network Processors

7.0DDR-SDRAM

7.1Introduction

This document is intended to be used as a guide for routing DDR, based on the Intel® IXDP465 Development Platform. It contains routing guidelines and simulation results for using x16 Thin Small Outline Package (TSOP) memory devices soldered onto the processor module.

As shown in Figure 28, the Intel® IXP45X and Intel® IXP46X Product Line of Network Processors support two banks of 32-bit wide non-Error Correcting Code (non-ECC) or 40-bit wide (ECC) DDR-266 memory with the ability for single-bit error correction or multi-bit error detection (ECC). The IXP45X/IXP46X network processors support un- buffered DRAM only in densities of 128/256/512 Mbit or 1 Gbit. Table 27 lists the signal groups used for the DDR interface.

In this document, the term IXP45X/IXP46X product line refers to both the IXP46X network processors (with DDR ECC) and IXP45X network processors (without DDR ECC).

Table 27.	DDR Signal Groups
	Group	Signal Name	Description	No of Single
				Ended Signals
	Clocks	DDRI_CK[2:0]	DDR-SDRAM Differential Clocks	0
		DDRI_CK_N[2:0]	DDR-SDRAM Inverted Differential Clocks	0
		DDRI_CB[7:0]	ECC Data	8
	Data	DDRI_DQ[31:0]	Data Bus	32
		DDRI_DQS[4:0]	Data Strobes	5
		DDRI_DM[4:0]	Data Mask	5
	Control	DDRI_CKE[1:0]	Clock Enable - one per bank	2
		DDRI_CS_N[1:0]	Chip Select - one per bank	2
		DDRI_MA[13:0]	Address Bus	14
		DDRI_BA[1:0]	Bank Select	2
	Command	DDRI_RAS_N	Row Address Select	1
		DDRI_CAS_N	Column Address Select	1
		DDRI_WE_N	Write Enable	1
			Total	73

	Intel® IXP45X and Intel® IXP46X Product Line of Network Processors
February 2007	HDD
Document Number: 305261, Revision: 004	75