Texas Instruments TMS570LC4357

ePWM Submodules www.ti.com
2000
SPNU563A–March 2018
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Enhanced Pulse Width Modulator (ePWM) Module
Table 35-1. ePWM Module Control and Status Register Set Grouped by Submodule (continued)
Name
Address
Offset
(1)
Size
(x16) Shadow
Privileged
Mode Write
Only? Description
Digital Compare Event Registers
DCACTL 60h 1 No Yes Digital Compare A Control Register
DCTRIPSEL 62h 1 No Yes Digital Compare Trip Select Register
DCFCTL 64h 1 No Yes Digital Compare Filter Control Register
DCBCTL 66h 1 No Yes Digital Compare B Control Register
DCFOFFSET 68h 1 Writes No Digital Compare Filter Offset Register
DCCAPCTL 6Ah 1 No Yes Digital Compare Capture Control Register
DCFWINDOW 6Ch 1 No No Digital Compare Filter Window Register
DCFOFFSETCNT 6Eh 1 No No Digital Compare Filter Offset Counter Register
DCCAP 70h 1 Yes No Digital Compare Counter Capture Register
DCFWINDOWCNT 72h 1 No No Digital Compare Filter Window Counter Register
35.2 ePWM Submodules
Eight submodules are included in every ePWM peripheral. Each of these submodules performs specific
tasks that can be configured by software.
35.2.1 Overview
Table 35-2 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 35.2.3 for relevant details.
Table 35-2. 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