Data Sheet

TestSolutionComponents
BIT Coverage
BITisaninitializationtest,runningatany
power-uporre-initializationcycle.This
meansitcanachieveveryhightest
confidencelevels(ortest‘coverage’)by
assumingcompleteownershipofallboard
resources,utilizingtheseinthemannerbest
suitedtothepurposeoftesting,rightdown
totheintimateregisterlevel.Veryhighcoverage
levelswithadetailederrorresolutioncan
onlybeachievedinthisway.ThoughtheBIT
coveragelevelvariesonindividualhardware
products,thislevelisgenerally95%orbetter.
BITexecutesbeforeanyoperatingsystem
orevenbootfirmware,passingcontrolto
theseuponcompletion.
BCSisacontinuoustestandoperateswhile
theapplicationandtheOSarerunning.
Thisprovidesearlywarningofproblems
totheapplication.InatypicalCOTSenvironment,
continuoustestsaregenerallymorelimited
inscopethaninitializationtests.Thisis
becausetheymustbenon-intrusive,i.e.
theiruseofresourceshastotakeinto
accountthatneithertheOS,noranylayered
softwarepackages,northeapplication,
canbedisturbed.(AlthoughCOTSoperating
systemshaveknown,stable,published
interfaces,theirinternaluseofhardware
resourcesisoftencomplex,largelyunpublished,
andassumedtobeexclusive.Suchusagealso
varieswitheachOStypeandeveneach
release.)Whilenon-intrusionmakesBCS
subjecttolimitationsontestconfidenceand
diagnosticresolution,itsmajordeviceusage
isviaOSmechanisms,andthusitdoesnot
conflictwiththeOSuseofresources.
BCSiscustomizedbyGEIntelligentPlatform
toeachparticularOStypeandrunsasan
OSthread.Itthusavoidsthedangercreated
iftheapplicationattemptstocallatraditional
initializationtestfirmware(writteninignorance
oftheparticularOSbeingusedandusually
assumingexclusivecontrol),toprovidea
‘continuous’test.Thiswilllikelycompromise
thetotalmachinestatebeforereturningto
theOSandapplicationlevel.BCSallows
continuoustestingevenwithaCOTS
operatingsystem.
Figure1representsthesoftwaremodules
thatGEIntelligentPlatformsupplies,showing
howBITandBCSfitintotheoverallpicture.
GEIntelligentPlatformprovidesallmodules
belowthedottedblackline.Atthelowest
level,BITandthebootfirmware(SilverChip,
PPCBootoraVxWorksBootROM)live
directlyabovethehardware.
Theseareself-containedmodulesthat
havenointeractionwithhigherlevels,
excepttopasscontrolanddatatothem
uponcompletion.Atthenextlevel,theBSP
formsthehardware-dependentportionof
theoperatingsystem,stilldirectlytouch-
inghardwarebutactuallyaspartofthe
contextoftheOSkernelitself.Additional
driversextendthisbasichardwarelayerto
supportperipheraldevices,andBCShas
similarcharacteristicstothese,dealing
directlywithhardwaredevicesbutasa
dedicatedOSthread.
BITandBCSformthekeyelementsofa
totalsystemtestphilosophythatallows
maximumtestconfidencefordeployed
systemsimplementedwithCOTShardware
andsoftware.BITprovidesveryhighcoverage
initializationtests,BCSprovidesnon-
intrusivebackgroundtestingthatis
co-operativewithCOTSoperatingsystems.
Straightforwardmethodsfortheaddition
ofcustomizedteststocovercustomer-
proprietaryitemsandspecialsystem
configurationscompletethepicture.
BitandBCS:
FeaturesandOperations
BIT Operation
BITanucBITexecutesinfunctionallayers
(seeFigureonfrontpage),eachproviding
theconfidencethatfurthertestingonthe
nextlayerisvalid.TheMinimumProcessing
Environment(MPE)executesfirst.This
setsupthebasicboardconfigurationand
performsteststoprovideconfidencein
thefundamentalprocessingcapability,
includingFlashchecksumsandtestsof
the(minimum)areasofmemoryrequired
forfurtherBITprogress.Testingthen
proceedstolocaldevices,PMCdaughter
cards,andfinallytootherGEIntelligent
Platformelementswithinthetotalsystem.
DeployedTestSolutions
Defaultpower-upconfigurationsfor
GEIntelligentPlatformboardsaretailored
togivetheoptimumsystemconfidence
undertheconstraintsoflimitedstart-up
times,notrequiringmorethan15seconds
toexecute,andlessonsomehardwares.
Thoughstart-uptimecanbetradedfor
coverage(viaconfigurationchanges)to
meettighterconstraints,BITalsofeatures
a‘faststart’option.Thisisveryusefulin
‘brown-out’conditions,particularlyinflight
applicationswherethesystemmustcome
backupagainimmediatelyafterapower
glitch.BITmonitorsabackplanepin(generally
connectedtoanelectro-mechanical
power-glitchdetector),andifthisisinthe
‘faststart’state,BITwillbypassalltests
andjumpstraighttotheoperatingsystem
orapplication.
Onceconfiguredtestshavecompleted,BIT
cantakeanumberofactions,suchasjump
totheapplicationorgointotheBIToption
menu.Fromthismenu,newtestconfigurations
canbemadeortestsruninteractively-for
example,toassistwithfielddiagnosis.
System Test Coverage
SystemTestCoveragewithinasystemcan
becontrolledbyanominatedBITmaster.
Inaddition,testsfordumbVMEperipheral
cardsfromtheGEIntelligentPlatformrange
arebuiltintostandardBITcode,allowing
thesecardstoalsoberecognizedand
testedfromtheBITmaster.Resultsare
co-ordinatedoverthewholesystem.
System-widememoryareas(e.g.local,over
PCI,overVME)canbetestedtoo,including
exercisingofblocktransfermodes.These
strategiesdelivercomprehensiveandco-
ordinatedsystemcoveragethatcanbe
tailoredtoparticularconfigurations.
BIT for PMC Product
BITforthePowerPCfamilyhasthecapability
touploadtestsfromarangeofGEIntelligent
PlatformPMCcardstogive‘plugandplay’
testcapability.Thetestsareheldinthe
BIOSPROMonthePMCcards,andare
uploadedandexecutedaspartofthemain
testsequence,afterMPEandBITlocal
devicetests.Theuploadedtestscancall
uponarangeofservicesfromthemainBIT
package,e.g.interruptconnectionandaccess
toBITconfigurationdata.Thisfeaturecan
assistwithfielddiagnosis,facilitatingeasy
‘swapping’ofsuspectPMCsbetweenPCI
slotsorhostboards.
Figure 1: Software Module