Texas Instruments TMS320x28xx, 28xxx manual Up-Down-Count Mode Symmetrical Waveform

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Action-Qualifier (AQ) Submodule

When using this configuration in practice, if you load CMPA/CMPB on zero, then use CMPA/CMPB values greater than or equal to 1. If you load CMPA/CMPB on period, then use CMPA/CMPB values less than or equal to TBPRD-1. This means there will always be a pulse of at least one TBCLK cycle in a PWM period which, when very short, tend to be ignored by the system.

Figure 2-20. Up-Down-Count Mode Symmetrical Waveform

Mode:Up-DownCount3 TBPRD=4

CAU=SET,CAD=CLEAR 2 0%-100%Duty

4

3

2

3

2

4

3

2

TBCNTR

TBCNTRDirection

Case1: CMPA =4,0%Duty

Case2: CMPA =3,25%Duty

Case3: CMPA =2,50%Duty

Case3: CMPA =1,75%Duty

Case4: CMPA =0,100%Duty

1

0

UP

DOWN

1 1

0

UP

1

0

DOWN

EPWMxA/EPWMxB

EPWMxA/EPWMxB

EPWMxA/EPWMxB

EPWMxA/EPWMxB

EPWMxA/EPWMxB

The PWM waveforms in Figure 2-21through Figure 2-26show some common action-qualifier configurations. The C-code samples in Example 2-2through Example 2-7shows how to configure an ePWM module for each case. Some conventions used in the figures and examples are as follows:

∙TBPRD, CMPA, and CMPB refer to the value written in their respective registers. The active register, not the shadow register, is used by the hardware.

∙CMPx, refers to either CMPA or CMPB.

∙EPWMxA and EPWMxB refer to the output signals from ePWMx

∙Up-Down means Count-up-and-down mode, Up means up-count mode and Dwn means down-count mode

∙Sym = Symmetric, Asym = Asymmetric

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ePWM Submodules

SPRU791D–November 2004–Revised October 2007

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Contents Reference Guide Submit Documentation Feedback Contents Controlling a 3-Phase Interleaved DC/DC Converter List of Figures Event-Trigger Socb Pulse Generator Simplified ePWM Module List of Tables Submit Documentation Feedback CPU Users Guides Related Documentation From Texas InstrumentsData Manuals Peripheral GuidesTools Guides Application ReportsTrademarks TMS320C28x, C28x are trademarks of Texas InstrumentsSubmit Documentation Feedback Introduction Introduction Submodule OverviewMultiple ePWM Modules ∙ ADC start-of-conversion signals EPWMxSOCA and EPWMxSOCB ∙ PWM output signals EPWMxA and EPWMxB∙ Trip-zone signals TZ1 to TZ6 ∙ Peripheral BusEPWM Submodules and Critical Internal Signal Interconnects Register MappingTime-Base Submodule Registers Offset Size NameDescription Counter-Compare Submodule RegistersEPWM Submodules Submodule Configuration Parameters Submodule Configuration Parameter or OptionOverview Example 2-1. Constant Definitions Used in the Code Examples TbupChpenable Time-Base TB Submodule Purpose of the Time-Base SubmoduleControlling and Monitoring the Time-base Submodule Time-Base Submodule RegistersRegister ∙ Up-Count Mode Key Time-Base Signals∙ Up-Down-Count Mode ∙ Down-Count ModeTime-Base Period Shadow Register ∙ Time-Base Period Shadow Mode∙ Time-Base Period Immediate Load Mode ∙ Active RegisterTime-Base Counter Synchronization Time-Base Counter Synchronization SchemeEPWM11SYNCI EPWM11SYNCO∙ EPWMxSYNCI Synchronization Input Pulse ∙ Software Forced Synchronization PulsePhase Locking the Time-Base Clocks of Multiple ePWM Modules Time-base Counter Modes and Timing WaveformsTime-Base Down-Count Mode Waveforms Counter-Compare CC Submodule 11. Counter-Compare SubmoduleCounter-Compare Submodule Registers Purpose of the Counter-Compare SubmoduleControlling and Monitoring the Counter-Compare Submodule Register Name Address Offset∙ Shadow Mode Count Mode Timing WaveformsCounter-Compare Submodule Key Signals ∙ Immediate Load ModeCTR=CMPA CTR=CMPBCTR = Cmpb Action-Qualifier AQ Submodule Purpose of the Action-Qualifier SubmoduleAction-Qualifier Submodule Registers ∙ Clear Low Action-Qualifier Submodule Possible Input Events∙ Set High ∙ ToggleTB Counter equals Actions 10. Action-Qualifier Event Priority for Down-Count Mode Action-Qualifier Event Priority for Up-Down-Count ModeAction-Qualifier Event Priority for Up-Count Mode Action-Qualifier Event PriorityUse up-down-count mode to generate an asymmetric PWM Waveforms for Common ConfigurationsUse up-down-count mode to generate a symmetric PWM When using up-count mode to generate an asymmetric PWM20. Up-Down-Count Mode Symmetrical Waveform Example 2-2. Code Sample for Figure TbctrValue EPWMxA EPWMxB Example 2-3. Code Sample for Figure Tbclk = SysclkoutExample 2-4. Code Sample for Figure EdgePosAExample 2-5. Code Sample for Figure Example 2-6. Code Sample for Figure TbctrExample 2-7. Code Sample for Figure EPWMxA EPWMxBControlling and Monitoring the Dead-Band Submodule Dead-Band Generator DB SubmodulePurpose of the Dead-Band Submodule 12. Dead-Band Generator Submodule Registers∙ Input Source Selection ∙ Output Mode ControlOperational Highlights for the Dead-Band Submodule ∙ Polarity ControlMode Description 13. Classical Dead-Band Operating Modes29. Dead-Band Waveforms for Typical Cases 0% Duty 100% Dead-Band Delay in μS FED = Dbfed × Ttbclk RED = Dbred × TtbclkControlling the PWM-Chopper Submodule PWM-Chopper PC SubmodulePurpose of the PWM-Chopper Submodule Operational Highlights for the PWM-Chopper SubmoduleWaveforms 31. PWM-Chopper Submodule Operational DetailsOne-Shot Pulse 16. Possible Pulse Width Values for Sysclkout = 100 MHzOSHTWTHz Duty Cycle Control PeriodTrip-Zone TZ Submodule Purpose of the Trip-Zone Submodule17. Trip-Zone Submodule Registers Controlling and Monitoring the Trip-Zone SubmoduleOperational Highlights for the Trip-Zone Submodule ∙ Cycle-by-Cycle CBCScenario a Example 2-8. Trip-Zone Configurations18. Possible Actions On a Trip Event Scenario B36. Trip-Zone Submodule Mode Control Logic Generating Trip Event InterruptsEvent-Trigger ET Submodule 37. Trip-Zone Submodule Interrupt LogicOperational Overview of the Event-Trigger Submodule 19. Event-Trigger Submodule Registers CTR=CMPB CTRD=CMPB41. Event-Trigger Interrupt Generator 42. Event-Trigger Soca Pulse Generator Submit Documentation Feedback Applications to Power Topologies Controlling Multiple Buck Converters With IndependentKey Configuration Capabilities Overview of Multiple ModulesCTR=0 EPWM1B CTR=CMPB Control of Four Buck Stages. Here FPWM1≠ FPWM2≠ FPWM3≠ FPWM4 Buck Waveforms for -3Note Only three bucks shown here Example 3-1. Configuration for Example in Figure 500Controlling Multiple Buck Converters With Same Frequencies Control of Four Buck Stages. Note FPWM2 = N x FPWM1Buck Waveforms for -5Note FPWM2 = FPWM1 Example 3-2. Code Snippet for Configuration in Figure Controlling Multiple Half H-Bridge HHB Converters Control of Two Half-H Bridge Stages FPWM2 = N x FPWM1Half-H Bridge Waveforms for -7Note Here FPWM2 = FPWM1 Controlling Dual 3-Phase Inverters for Motors ACI and Pmsm Example 3-3. Code Snippet for Configuration in FigureEPWM1A 10 -Phase Inverter Waveforms for -9Only One Inverter Shown Example 3-4. Code Snippet for Configuration in Figure 11. Configuring Two PWM Modules for Phase Control Controlling a 3-Phase Interleaved DC/DC Converter Controlling a 3-Phase Interleaved DC/DC Converter13. Control of a 3-Phase Interleaved DC/DC Converter 14 -Phase Interleaved DC/DC Converter Waveforms for Figure Example 3-5. Code Snippet for Configuration in Figure 15. Controlling a Full-H Bridge Stage FPWM2 = FPWM1 16. ZVS Full-H Bridge Waveforms Example 3-6. Code Snippet for Configuration in Figure Submit Documentation Feedback Proper Interrupt Initialization Procedure PWM-Chopper Submodule Control RegisterTrip-Zone Submodule Control and Status Registers Time-Base Period Register Tbprd Field Descriptions Time-Base Phase Register Tbphs Field DescriptionsTime-Base Submodule Registers Time-Base Counter Register Tbctr Field DescriptionsTime-Base Control Register Tbctl Field Descriptions Bit Field Value DescriptionSoftware Forced Synchronization Pulse Counter-Compare Submodule Registers Time-Base Status Register Tbsts Field DescriptionsBit Field Counter-Compare a Register Cmpa Field Descriptions Counter-Compare B Register Cmpb Field DescriptionsBits Name Description Action-Qualifier Submodule Registers Counter-Compare Control Register Cmpctl Field DescriptionsCBD CBU CAD CAU PRD ZRO Bits NameCBD 10. Action-Qualifier Output B Control Register Aqctlb Rldcsf Otsfb Actsfb Otsfa Actsfa RldcsfCsfb Csfa Dead-Band Submodule Registers CsfbInmode Polsel Outmode Inmode Name Value Description PWM-Chopper Submodule Control Register16. PWM-Chopper Control Register Pcctl Bit Descriptions ReservedTrip-Zone Submodule Control and Status Registers PWM-Chopper Control Register Pcctl Bit DescriptionsChpduty OSHT6 OSHT6 OSHT5 OSHT4 OSHT3 OSHT2 OSHT1CBC6 CBC5 CBC4 CBC3 CBC2 CBC1 CBC6TZB 18. Trip-Zone Control Register Tzctl Field DescriptionsTZB TZA OST CBC20. Trip-Zone Flag Register Tzflg Field Descriptions OST CBC INTEvent-Trigger Submodule Registers 21. Trip-Zone Clear Register Tzclr Field Descriptions22. Trip-Zone Force Register Tzfrc Field Descriptions 23. Event-Trigger Selection Register Etsel 24. Event-Trigger Prescale Register Etps Field Descriptions Name Description24. Event-Trigger Prescale Register Etps Field Descriptions Socb Soca25. Event-Trigger Flag Register Etflg Field Descriptions 26. Event-Trigger Clear Register Etclr Field DescriptionsSocb Proper Interrupt Initialization Procedure 27. Event-Trigger Force Register Etfrc Field Descriptions116 Table A-1. Changes for Revision D Location Modifications, Additions, and DeletionsAppendix a Important Notice