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2.2Time-Base(TB)Submodule
CTR = CMPB
CTR = CMPA
CTR_Dir
CTR = 0
CTR = PRD
Dead
Band
(DB)
Counter
Compare
(CC)
Action
Qualifier
(AQ)
EPWMxA
EPWMxB
CTR = CMPB
CTR = 0
EPWMxINT
EPWMxSOCA
EPWMxSOCB
EPWMxA
EPWMxB
TZ1
to TZ6
CTR = CMPA
Time-Base
(TB)
CTR = PRD
CTR = 0
CTR_Dir
EPWMxSYNCI
EPWMxSYNCO
EPWMxTZINT
PWM-
chopper
(PC)
Event
Trigger
and
Interrupt
(ET)
Trip
Zone
(TZ)
GPIO
MUX
ADC
PIE
PIE
2.2.1PurposeoftheTime-BaseSubmodule
Time-Base(TB)Submodule
EachePWMmodulehasitsowntime-basesubmodulethatdeterminesalloftheeventtimingforthe
ePWMmodule.Built-insynchronizationlogicallowsthetime-baseofmultipleePWMmodulestowork
togetherasasinglesystem.Figure2-1illustratesthetime-basemodule'splacewithintheePWM.
Figure2-1.Time-BaseSubmoduleBlockDiagram
Youcanconfigurethetime-basesubmoduleforthefollowing:
•SpecifytheePWMtime-basecounter(TBCTR)frequencyorperiodtocontrolhowofteneventsoccur.
•Managetime-basesynchronizationwithotherePWMmodules.
•MaintainaphaserelationshipwithotherePWMmodules.
•Setthetime-basecountertocount-up,count-down,orcount-up-and-downmode.
•Generatethefollowingevents:
–CTR=PRD:Time-basecounterequaltothespecifiedperiod(TBCTR=TBPRD).
–CTR=Zero:Time-basecounterequaltozero(TBCTR=0x0000).
•Configuretherateofthetime-baseclock;aprescaledversionoftheCPUsystemclock
(SYSCLKOUT).Thisallowsthetime-basecountertoincrement/decrementataslowerrate.
SPRU791D–November2004–RevisedOctober2007ePWMSubmodules23
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