Intel IXP43X manual DDRII/I Sdram Initialization, DDRII/I Sdram Interface Pin Description Sheet 2

Intel® IXP43X Product Line of Network Processors—Hardware Design Guidelines

Table 4.	DDRII/I SDRAM Interface Pin Description (Sheet 2 of 2)
		Type		VTT
Name			Device-Pin Connection	Terminatio	Description
		Field
				n
					ECC Bus — Eight-bit error correction code
					which accompanies the data on D_DQ[31:0]/
D_CB[7:0] /		I/O	Connect to ECC memory devices.	Yes	DDR_DQ[31:0].
DDR_CB[7:0]					When ECC is disabled and not being used in a
					system design, these signals can be left un-
					connected.
					Data Strobes Differential — Strobes that
					accompany the data to be read or written from
			Connect DQS[3:0] to devices with		the DDRII/I SDRAM devices. Data is sampled
D_DQS[4:0] /					on the negative and positive edges of these
		I/O	data signals and DQS[4] to	Yes
DDR_DQS[4:0]					strobes. D_DQS[3:0]/DDR_DQS[3:0] are
			devices with ECC signals.
					intended to correspond to each byte of a word
					of data. D_DQS[4]/DDR_DQS[4] is intended to
					be utilized for the ECC byte of data.
					Clock enables — One clock after D_CKE[1:0]/
					DDR_CKE[1:0] is de-asserted, data is latched
			Use one CKE per bank, never mix		on D_DQ[31:0]/DDR_DQ[31:0] and
D_CKE[1:0] /					D_CB[7:0]/DDR_CB[7:0]. Burst counters
		O	the CKE on the same bank. Use	Yes
					within DDRII/I SDRAM device are not
DDR_CKE[1:0]			CKE[0] for bank0 and CKE[1] for
					incremented. De-asserting this signal places
			bank1
					the DDRII/I SDRAM in self-refresh mode. For
					normal operation, D_CKE[1:0]/DDR_CKE[1:0]
					must be asserted.
D_ODT[1:0]					On Die Termination Control — Turns on DDR II
					SDRAM termination during writes.
					Compensation for DDR OCD (analog) DDRII
D_RES[2:1]			Refer to Figure 27		mode only. This function is not enable and
					special connection is required.
					Compensation Voltage Reference (analog) for
D_SLWCRES			Refer to Figure 27		DDR driver slew rate control connected
					through a resistor to D_CRES0.
					Compensation Voltage Reference (analog) for
D_IMPCRES			Refer to Figure 27		DDR driver impedance control connected
					through a resistor to D_CRES0.
					Analog VSS Ref Pin (analog) both D_SLWCRES
					and D_IMPCRES signals connect to this pin
					through a reference resistor. For DDRII/I
					respectively:
D_CRES0		O	Tied off to a resistor	Tied off to a	- 285 / 387Ohm Resistor connected to
				resistor	DDR_IMPCRES used for process and
					temperature adjustments.
					- 825 / 845Ohm Resistor connected to
					DDR_SLWCRES used for process and
					temperature adjustments.
					DDRII/IDDRII/I SDRAM Voltage Reference — is
D_VREF / DDR_VREF		I	VCCDDR/2	VCCDDR/2	used to supply the reference voltage to the
					differential inputs of the memory controller
					pins.

3.2.2DDRII/I SDRAM Initialization

For instructions on DDRII/I SDRAM initialization, refer to DDR SDRAM Initialization subsection in the Memory Controller chapter of the Intel® IXP43X Product Line of Network Processors Developer’s Manual.

Intel® IXP43X Product Line of Network Processors
HDG	April 2007
20	Document Number: 316844; Revision: 001US