u-blox ANTARIS 4 - Page 67


your position is our focus
Wakeup conditions
Pin Trigger
EXTINT0
Risingedge
RxD1orRxD2
Fallingedge
Table 13: Possibilities to wakeup the receiver

thefirstbytesmaygetlost.

DuringoffstatedrivingRESET_N lowcanwakethereceiverup.Ifthereceiverconfigurationhasnotbeensaved
inBBR,thereceiverwillloosetheactualconfigurationandreverttopreviousconfiguration.
4.2.7.4 Waking up the ANTARIS
®
4 GPS Receiver by RTC
The ANTARIS
®
4 GPS Receiver has an internal RTC, which is used to set a timeout to wake-up the receiver
withoutanyexternalsignal.ThisisusedintheFixNOW™Mode(FXN)(seeSection 4.2.7).
 Note TheRTCwake-uptimeoutcanonlybesetinternallybytheFixNOW™function.Thereisnoexternal
or
manualaccesstothewakeuptimeout.
heFixNOW™modecontrolsthePowerSupplyfortheactiveantennaconnectedtotheRF_INpin.Thevoltage
supply shutdownwhenthereceivergoestoOffState.
4.2.7.6 Functional Overv
T has several  to optimize the G r-Performan
t specific user
applic ents:
Note When waking up a receiver from sleep- or backup state with a serial message (RxD1 or RxD2), a
number (at least 8) of 0xFFcharactersshallbe send prior tothe RXM-POSREQ message. Otherwise
Note WhenwakinguptheANTARIS
®
4 GPSReceiverbyEXTINT0apositionwillbecalculated.
4.2.7.5 Active Antenna Power Control with FixNOW™
T
willbe
iew
he FXN mode
requirem
parameters  PS- and Powe ce
to mee
ation
Parameter Descrip n tio
T_on [s]
Timethereceiverstaysonafterachievingthefirstpositionfixwiththeflag'positionwithinlimits'set.
IfT_onissetto0s,thereceiverwillshutdownafterthefirstvalidfixassoonastheRTCiscalibrated.Ifanew
iverwillautomaticallyincreasethe"startup
ephemerisisneededtoachievethe
definedaccuracy,therece
acquisitiontimeT_acq".
T_off [s]
TimethereceiverstaysinOffState
Base TOW [s]
AlignmentofT_acq(start-up)toGPSTimeofWeek.
T_acq [s]
TimethereceivertriestoacquireSVbeforegoingtoOffState,ifSVacquisitionisnotsuccessful.
T_acq_off [s]
TimethereceiverstaysinOffState,whenSVacquisitionwasnotsuccessful.
T_reacq [s]
Timethereceivertriestoreacquireassoonasaskyobstructionhappensandno2D or3Dfixispossible.
T_reacq_off [s]
TimethereceiverstaysinOffState,afterreacquisition wasnotsuccessful.
Table 14: FXN mode parameter description
GPSModules-SystemIntegrationManual(SIM)(incl.ReferenceDesign) ReceiverDescription
GPS.G4-MS4-05007-A1
  Page 67