Intel IXP43X manual Timing Relationships, DDR II/I Sdram Interface -- Signal Timings, Dqs

Page 79

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

Table 31.

DDR II/I SDRAM Interface -- Signal Timings

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Symbol

 

Parameter

Minimum

Nom.

 

Maximum

Units

Notes

 

 

 

 

 

 

 

 

 

 

 

 

 

TVB1

 

DQ, CB and DM write output valid time

1146

 

 

 

ps

1

 

 

 

before DQS.

 

 

 

 

 

TVA1

 

DQ, CB and DM write output valid time after

1146

 

 

 

ps

1

 

 

 

DQS.

 

 

 

 

 

TVB3

 

Address and Command write output valid

3021

 

 

 

ps

1, 4

 

 

 

before CK rising edge.

 

 

 

 

 

TVA3

 

Address and Command write output valid

3021

 

 

 

ps

1, 4

 

 

 

after CK rising edge.

 

 

 

 

 

TVB4

 

DQ, CB and DM read input valid time before

948

 

 

 

ps

2

 

 

 

DQS rising or falling edges.

 

 

 

 

 

TVA4

 

DQ, CB and DM read input valid time after

948

 

 

 

ps

2

 

 

 

DQS rising or falling edges.

 

 

 

 

 

TVB5

 

CS_N[1:0] control valid before CK rising

3021

 

 

 

ps

4

 

 

 

edge.

 

 

 

 

 

TVA5

 

CS_N[1:0] control valid after CK rising edge.

3021

 

 

 

ps

4

 

 

TVB6

 

DQS write preamble duration.

 

5625

 

 

ps

3

 

 

TVA6

 

DQS write postamble duration.

 

3750

 

 

ps

3

 

 

TV7

 

DQ, CB, and DM pulse width (tDIPW)

 

1750

 

 

ps

1

 

 

Notes:

 

 

 

 

 

 

 

 

 

 

1.

See Figure 29, “DDR SDRAM Write Timings” on page 77

 

 

 

 

 

 

 

2.

See Figure 30, “DDR SDRAM Read Timings” on page 77. The specified minimum requirements for “Data to

 

 

 

strobe read setup” and “Data from strobe read hold” are determined with the DQS delay programmed for

 

 

 

90 degree phase shift.

 

 

 

 

 

 

 

 

3.

See Figure 31, “DDR - Write Preamble/Postamble Duration” on page 78

 

 

 

 

 

4.

Address/Command pin group; RAS_N, CAS_N, WE_N, MA[13:0], BA[1:0]

 

 

 

 

 

5.

Designed to JEDEC specification; it is recommended that IBIS models should be used to verify signal

 

 

 

integrity on individual designs

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7.3.1.0.1Printed Circuit Board Layer Stackup

The layer stackup used for the Intel® IXP435 Multi-Service Residential Gateway Reference Platform is a 6-layer, printed circuit board with four signal layers and two plane layers.

Details on the voltage reference layout are available in the CAD database or Gerber files database for the Intel® IXP435 Multi-Service Residential Gateway Reference Platform.

7.3.2Timing Relationships

The routing guidelines presented in the following subsections define the recommended routing topologies, trace width, spacing geometries, and typical routed lengths for each signal group. These parameters are recommended to achieve optimal signal integrity and timing.

All signal groups are length matched to the DDR clocks. The clocks on the processor module are length matched to within ±10 mils of each other. Once this overall clock length for any given DDR differential clock is determined, the command and control signals can be routed to within the timing specified. A simple summary of the timing results for each signal group is provided in Table 32 on page 80.

Control/Command Group to Clock Summary:

The maximum allowable difference from any command/control signal to the clock is ±0.6 ns.

 

Intel® IXP43X Product Line of Network Processors

April 2007

HDG

Document Number: 316844; Revision: 001US

79

Image 79
Contents Hardware Design Guidelines Intel IXP43X Product Line of Network ProcessorsHDG Intel IXP43X Product Line of Network ProcessorsApril Contents Figures Tables Document Number 316844 Revision 001US Date Revision Description § §001 Initial release HDG Chapter Name Description Content OverviewTerm Explanation Related DocumentationAcronyms List of Acronyms and Abbreviations Sheet 1List of Acronyms and Abbreviations Sheet 2 OverviewHDG Intel IXP435 Network Processor Block Diagram Typical Applications System Memory Map System Architecture DescriptionIntel IXP43X Product Symbol Description Soft Fusible FeaturesSignal Type Definitions Soft Fusible Features Sheet 1Ethernet Soft Fusible Features Sheet 2USB Host Each USB can be Enable separately DDRII/I Sdram InterfaceName Device-Pin Connection Terminatio Description Field Signal InterfaceDDRII/I Sdram Interface Pin Description Sheet 1 TypeDDRII/I Sdram Interface Pin Description Sheet 2 DDRII/I Sdram InitializationExpansion Bus Expansion Bus Signal Recommendations Sheet 1Type Pull Name Recommendations Field Down Name Type Pull Recommendations Field Down Reset Configuration StrapsExpansion Bus Signal Recommendations Sheet 2 Boot/Reset Strapping Configuration Sheet 1Boot/Reset Strapping Configuration Sheet 2 MHz Setting Intel XScale Processor Operation Speed3 8-Bit Device Interface Intel XScale Processor Cfg0 Cfg1 Cfgenn Actual Core Speed4 16-Bit Device Interface 16-Bit Device Interface Flash InterfaceFlash Interface Example Uart InterfaceUart Signal Recommendations Uart Interface Example MII InterfaceMII NPE a Signal Recommendations Signal Interface MIIMII NPE C Signal Recommendations Sheet 1 MAC Management Signal Recommendations NPE a and NPE C MII NPE C Signal Recommendations Sheet 2Device Connection, MII MII Interface Example Gpio InterfaceUSB Interface Gpio Signal RecommendationsDesign Notes Name Type Pull Description Field Down USB Host Signal RecommendationsCommon Mode Choke Host Device Utopia Level 2/MIIA Utopia Level 2 InterfaceType Pull Name Description Field Down Utpopfci UTPOPDATA4UTPOPDATA75 UTPOPADDR40ETHARXDATA30 Etharxclk ClavUtpipfci UtpipsocUTPIPADDR40 UTPIPDATA5UTPIPDATA6 UTPIPDATA7Device Connection HSS InterfaceHSSRXDATA0 High-Speed, Serial InterfaceHSSTXDATA0 HSSTXCLK0HSS Interface Example SSP InterfaceSynchronous Serial Peripheral Port Interface Serial Flash and SSP Port SPI Interface Example PCI InterfacePCI Controller Sheet 1 Pciclkin PCI Interface Block DiagramPCI Controller Sheet 2 PciintanType Option Description Name Device-Pin Connection Field Connect signal to same pin between PCI Parity Two devicesPCI Option Interface PCI Host/Option Interface Pin Description Sheet 1Type Option Name Device-Pin Connection Description Field On the Option device, these signals are notSignal PCIREQN0 to one PCIREQN30 inputs to the Host PCI Host/Option Interface Pin Description Sheet 2PCI Host/Option Interface Pin Description Sheet 3 Jtag InterfaceClock Oscillator Clock SignalsClock Signals Input System ClockRecommendations for Crystal Selection Power Supply PowerNominal Name Voltage Description VCC Decoupling Power SequenceReset Timing Decoupling Capacitance Recommendations§ § Component Selection Component PlacementPCB Overview General RecommendationsStack-Up Selection Component Placement on a PCBControlled-impedance traces Low-impedance power distribution Layer Stackup General Layout Guidelines General Layout and Routing GuideGeneral Component Spacing Signal Changing Reference PlanesGood Design Practice for VIA Hole Placement Pad-to-Pad Clearance of Passive Components to a PGA or BGA Clock Signal ConsiderationsUSB V2.0 Considerations MII Signal ConsiderationsCrosstalk EMI Design Considerations Power and Ground PlaneTrace Impedance § § Tcyc = 30 nSec Tval = 11 nSec Tprop = 10 nSec Electrical InterfaceTopology @33 MHzPCI Address/Data Routing Guidelines Clock DistributionParameter Routing Guidelines PCI Clock Routing Guidelines Trace Length LimitsRouting Guidelines Signal LoadingIntroduction Ddrii / Ddri SdramDcasn / Ddrcasn DDRII/I Signal GroupsGroup Signal Name Description Drasn / DdrrasnDDR Sdram Sizea Supported Ddri 32-bit Sdram ConfigurationsSupported Ddrii 32-bit Sdram Configurations Supported Ddri 16-bit Sdram ConfigurationsTechnology Arrangement Banks Supported Ddrii 16-bit Sdram ConfigurationsDDRII/DDRI Rcomp and Slew Resistances Pin Requirements Address Size Leaf Select TotalDdrii OCD Pin Requirements DDR-II Symbol Parameter Units Min MaxDDR Clock Timings DDR Sdram Write Timings Symbol Parameter Minimum Nominal Maximum Units DDRII-400 MHz Interface -- Signal TimingsPrinted Circuit Board Layer Stackup DDR II/I Sdram Interface -- Signal TimingsSymbol Parameter Minimum Nom Maximum Units Timing RelationshipsGroup Signal Name Length mil Signal Package Lengths Sheet 1Timing Relationships Signal Package Lengths Sheet 2 Clock Group Signal Package Lengths Sheet 3Parameter Definition Data and Control GroupsDCB70/DDRCB70, DDQ310 / DDRDQ310 Ddrii Data and Control Signal Group Routing GuidelinesSignal Group Members Ddrii Command Signal Group Routing Guidelines§ §