Datasheet

www.ti.com ePWM Submodules
Table 34-1. ePWM Module Control and Status Register Set Grouped by Submodule (continued)
Privileged
Address Size Mode Write
Name Offset
(1)
(x16) Shadow Only? Description
DCFWINDOW 6Eh 1 No No Digital Compare Filter Window Register
DCFOFFSETCNT 6Ch 1 No No Digital Compare Filter Offset Counter Register
DCCAP 72h 1 Yes No Digital Compare Counter Capture Register
DCFWINDOWCNT 70h 1 No No Digital Compare Filter Window Counter Register
34.2 ePWM Submodules
Eight submodules are included in every ePWM peripheral. Each of these submodules performs specific
tasks that can be configured by software.
34.2.1 Overview
Table 34-2 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 Section 34.2.3 for relevant details.
Table 34-2. Submodule Configuration Parameters
Submodule Configuration Parameter or Option
Time-base (TB)
• Scale the time-base clock (TBCLK) relative to the system clock (VCLK3).
• 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.
• 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.
Counter-compare (CC)
• 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
Action-qualifier (AQ)
• 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
Dead-band (DB)
• 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.
1717
SPNU562–May 2014 Enhanced Pulse Width Modulator (ePWM) Module
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