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7.2
ePWM Submodules
Eight submodules are included in every ePWM peripheral. Each of these submodules performs specific
tasks that can be configured by software.
7.2.1 Overview
Table 7-3
lists the eight key submodules together with a list of their main configuration parameters. For
example, if you need to adjust or control the duty cycle of a PWM waveform, then you should see the
counter-compare submodule in
Submodule
Time-base (TB)
Counter-compare (CC)
Action-qualifier (AQ)
Dead-band (DB)
PWM-chopper (PC)
SPRUH22I – April 2012 – Revised November 2019
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Section 7.2.3
for relevant details.
Table 7-3. Submodule Configuration Parameters
Configuration Parameter or Option
• Scale the time-base clock (TBCLK) relative to the system clock (SYSCLKOUT).
• Configure the PWM time-base counter (TBCTR) frequency or period.
• Set the mode for the time-base counter:
–
count-up mode: used for asymmetric PWM
–
count-down mode: used for asymmetric PWM
–
count-up-and-down mode: used for symmetric PWM
• Configure the time-base phase relative to another ePWM module.
• Synchronize the time-base counter between modules through hardware or software.
• Configure the direction (up or down) of the time-base counter after a synchronization event.
• Simultaneous writes to the TBPRD registers on all PWM's corresponding to the configuration on
EPWMXLINK.
• Configure how the time-base counter will behave when the device is halted by an emulator.
• Specify the source for the synchronization output of the ePWM module:
–
Synchronization input signal
–
Time-base counter equal to zero
–
Time-base counter equal to counter-compare B (CMPB)
–
No output synchronization signal generated.
• Specify the PWM duty cycle for output EPWMxA and/or output EPWMxB
• Specify the time at which switching events occur on the EPWMxA or EPWMxB output
• Specify the programmable delay for interrupt and SOC generation with additional comparators
• Simultaneous writes to the CMPA, CMPB, CMPC, CMPD registers on all PWM's corresponding
to the configuration on EPWMXLINK.
• Specify the type of action taken when a time-base or counter-compare submodule event occurs:
–
No action taken
–
Output EPWMxA and/or EPWMxB switched high
–
Output EPWMxA and/or EPWMxB switched low
–
Output EPWMxA and/or EPWMxB toggled
• Force the PWM output state through software control
• Configure and control the PWM dead-band through software
• Control of traditional complementary dead-band relationship between upper and lower switches
• Specify the output rising-edge-delay value
• Specify the output falling-edge delay value
• Bypass the dead-band module entirely. In this case the PWM waveform is passed through
without modification.
• Option to enable half-cycle clocking for double resolution.
• Allow ePWMxB phase shifting with respect to the ePWMxA output.
• Create a chopping (carrier) frequency.
• Pulse width of the first pulse in the chopped pulse train.
• Duty cycle of the second and subsequent pulses.
• Bypass the PWM-chopper module entirely. In this case the PWM waveform is passed through
without modification.
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Enhanced Pulse Width Modulator (ePWM) Module
ePWM Submodules
641