Texas Instruments TMS320x28xx, 28xxx manual

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Time-Base (TB) Submodule

2.2.4 Phase Locking the Time-Base Clocks of Multiple ePWM Modules

The TBCLKSYNC bit can be used to globally synchronize the time-base clocks of all enabled ePWM modules on a device. This bit is part of the DSPs clock enable registers and is described in the specific device version of the System Control and Interrupts Reference Guide listed in Section 1. When TBCLKSYNC = 0, the time-base clock of all ePWM modules is stopped (default). When TBCLKSYNC = 1, all ePWM time-base clocks are started with the rising edge of TBCLK aligned. For perfectly synchronized TBCLKs, the prescaler bits in the TBCTL register of each ePWM module must be set identically. The proper procedure for enabling the ePWM clocks is as follows:

1.Enable the individual ePWM module clocks. This is described in the specific device version of the System Control and Interrupts Reference Guide listed in Section 1.

2.Set TBCLKSYNC = 0. This will stop the time-base clock within any enabled ePWM module.

3.Configure the prescaler values and desired ePWM modes.

4.Set TBCLKSYNC = 1.

2.2.5Time-base Counter Modes and Timing Waveforms

The time-base counter operates in one of four modes:

∙Up-count mode which is asymmetrical.

∙Down-count mode which is asymmetrical.

∙Up-down-count which is symmetrical

∙Frozen where the time-base counter is held constant at the current value

To illustrate the operation of the first three modes, the following timing diagrams show when events are generated and how the time-base responds to an EPWMxSYNCI signal.

Figure 2-7. Time-Base Up-Count Mode Waveforms

	TBCTR[15:0]
	0xFFFF
	TBPRD
	(value)
	TBPHS
	(value)
	0000
	EPWMxSYNCI
	CTR_dir
	CTR = zero
	CTR = PRD
	CNT_max
30	ePWM Submodules	SPRU791D–November 2004–Revised October 2007

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Texas Instruments TMS320x28xx, 28xxx manual Phase Locking the Time-Base Clocks of Multiple ePWM Modules

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 Guides Tools Guides Application Reports Trademarks TMS320C28x, C28x are trademarks of Texas Instruments Submit Documentation Feedback Introduction Introduction Submodule Overview Multiple ePWM Modules ∙ ADC start-of-conversion signals EPWMxSOCA and EPWMxSOCB ∙ PWM output signals EPWMxA and EPWMxB∙ Trip-zone signals TZ1 to TZ6 ∙ Peripheral Bus EPWM Submodules and Critical Internal Signal Interconnects Register Mapping Time-Base Submodule Registers Offset Size NameDescription Counter-Compare Submodule Registers EPWM Submodules Submodule Configuration Parameters Submodule Configuration Parameter or OptionOverview Example 2-1. Constant Definitions Used in the Code Examples Tbup Chpenable Time-Base TB Submodule Purpose of the Time-Base Submodule Controlling and Monitoring the Time-base Submodule Time-Base Submodule RegistersRegister ∙ Up-Count Mode Key Time-Base Signals∙ Up-Down-Count Mode ∙ Down-Count Mode Time-Base Period Shadow Register ∙ Time-Base Period Shadow Mode∙ Time-Base Period Immediate Load Mode ∙ Active Register Time-Base Counter Synchronization Time-Base Counter Synchronization Scheme EPWM11SYNCI EPWM11SYNCO ∙ EPWMxSYNCI Synchronization Input Pulse ∙ Software Forced Synchronization Pulse Phase Locking the Time-Base Clocks of Multiple ePWM Modules Time-base Counter Modes and Timing Waveforms Time-Base Down-Count Mode Waveforms Counter-Compare CC Submodule 11. Counter-Compare Submodule Counter-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 Mode CTR=CMPA CTR=CMPB CTR = Cmpb Action-Qualifier AQ Submodule Purpose of the Action-Qualifier SubmoduleAction-Qualifier Submodule Registers ∙ Clear Low Action-Qualifier Submodule Possible Input Events∙ Set High ∙ Toggle TB 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 Priority Use 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 PWM 20. Up-Down-Count Mode Symmetrical Waveform Example 2-2. Code Sample for Figure Tbctr Value EPWMxA EPWMxB Example 2-3. Code Sample for Figure Tbclk = Sysclkout Example 2-4. Code Sample for Figure EdgePosA Example 2-5. Code Sample for Figure Example 2-6. Code Sample for Figure Tbctr Example 2-7. Code Sample for Figure EPWMxA EPWMxB Controlling 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 Control Mode Description 13. Classical Dead-Band Operating Modes 29. Dead-Band Waveforms for Typical Cases 0% Duty 100% Dead-Band Delay in μS FED = Dbfed × Ttbclk RED = Dbred × Ttbclk Controlling the PWM-Chopper Submodule PWM-Chopper PC SubmodulePurpose of the PWM-Chopper Submodule Operational Highlights for the PWM-Chopper Submodule Waveforms 31. PWM-Chopper Submodule Operational Details One-Shot Pulse 16. Possible Pulse Width Values for Sysclkout = 100 MHzOSHTWTHz Duty Cycle Control Period Trip-Zone TZ Submodule Purpose of the Trip-Zone Submodule 17. Trip-Zone Submodule Registers Controlling and Monitoring the Trip-Zone SubmoduleOperational Highlights for the Trip-Zone Submodule ∙ Cycle-by-Cycle CBC Scenario a Example 2-8. Trip-Zone Configurations18. Possible Actions On a Trip Event Scenario B 36. Trip-Zone Submodule Mode Control Logic Generating Trip Event Interrupts Event-Trigger ET Submodule 37. Trip-Zone Submodule Interrupt Logic Operational Overview of the Event-Trigger Submodule 19. Event-Trigger Submodule Registers CTR=CMPB CTRD=CMPB 41. Event-Trigger Interrupt Generator 42. Event-Trigger Soca Pulse Generator Submit Documentation Feedback Applications to Power Topologies Controlling Multiple Buck Converters With Independent Key Configuration Capabilities Overview of Multiple Modules CTR=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 500 Controlling Multiple Buck Converters With Same Frequencies Control of Four Buck Stages. Note FPWM2 = N x FPWM1 Buck 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 FPWM1 Half-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 Figure EPWM1A 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 Converter 13. 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 Descriptions Time-Base Control Register Tbctl Field Descriptions Bit Field Value Description Software 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 Descriptions CBD 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 Reserved Trip-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 CBC6 TZB 18. Trip-Zone Control Register Tzctl Field DescriptionsTZB TZA OST CBC 20. Trip-Zone Flag Register Tzflg Field Descriptions OST CBC INT Event-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 Description 24. Event-Trigger Prescale Register Etps Field Descriptions Socb Soca 25. 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 Descriptions 116 Table A-1. Changes for Revision D Location Modifications, Additions, and Deletions Appendix a Important Notice