RadiSys ATCA-5400 RTM Especificaciones descargar pdf (Pagina 38)

Components and Subsystems

Real-time clock

TheICHincludesanintegratedreal‐timeclock(RTC)thatkeepstrackofthetimeofday

anddate.TheRTCcircuitryincludes256bytesofcapacitor‐backedCMOSRAM.TheRT Cis

derivedfroma32.768KHzcrystalwiththefollowingspecifications:

• Frequencytolerance@25°C:±20ppm

• Frequencystability:maximumof‐0.04ppm/(°C)

•AgingF/f(firstyear@25°C):±3ppm

•±20ppmfrom0‐55°Candaging1ppm/year

Whenpowerisremovedfromtheboard,thetimeanddatearemaintainedbyan

electrolyticcapacitorforuptotwodays.Whenthechassisisturnedon,theRTCgets

powerfromtheIPMI3.3Vpowersupply,whichallowsthecapacitortobegincharging

beforetheCPMpayloadpoweristurnedon.

RTC date ranges and default initial dates

ThefollowingarevaliddaterangesanddefaultinitialdatesthatcanbesetintheRTC

throughtheBIOS.ValuesvarybasedontheBIOSversion.

•BIOSversion01.01.32andbelow:

Validdaterange:01/01/2005‐12/31/2099

Defaultinitialdate:01/01/2005

•BIOSversion01.01.33andabove:

Validdaterange:01/01/1998‐12/31/2099

Defaultinitialdate:01/01/2005

SeethehelpsectionintheBIOSSetupmainmenuforassistancesettingthedateforthe

RTC.

SMBus controller and multiplexers

TheICHincludesaSMBus2.0‐complianthostcontroller,whichallowstheCPUtoinitiate

communicationwithSMBusslaveperipheralsandI

C‐compatibledevices.TwoSMBus

multiplexersgivetheIPMCaccesstotheICHslaveregistersandtotheDIMMtemperature

sensors.RefertoI

CandSMBusmaponpage 163forinformationonthedevices

connectedtotheSMBus.

TheslaveinterfaceallowsanexternalmastertoreadfromorwritetotheICH.Writecycles

canbeusedtocausecertaineventsortopassmessages.Readcyclescanbeusedto

determinethe

stateofvariousstatusbits.TheICH’sinternalhostcontrollercannotaccess

theinternalslaveinterface.

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RadiSys ATCA-5400 RTM Especificaciones Pagina 38