Introduction
668
SPRUHE8E – October 2012 – Revised November 2019
Copyright © 2012–2019, Texas Instruments Incorporated
C28 Enhanced Pulse Width Modulator (ePWM) Module
7.1
Introduction
This chapter includes an overview of the module and information about each of its submodules:
•
Time-Base Module
•
Counter Compare Module
•
Action Qualifier Module
•
Dead-Band Generator Module
•
PWM Chopper (PC) Module
•
Trip Zone Module
•
Event Trigger Module
•
Digital Compare Module
ePWM Type 2 is fully compatible to the Type 1 module. Type 2 has the following enhancements in
addition to the Type 1 features:
•
New Registers added at upper page offset
Additional registers are required for new features on ePWM Type 2. ePWM register set for each
module has been expanded from 64 16-bit words to 128 16-bit words.
•
High Resolution Dead-Band Capability
High-Resolution capability is added to Dead-band RED and FED in half-cycle clocking mode.
•
Dead-Band Generator Module Enhancements
ePWM Type 2 has features to enable both RED and FED on either PWM outputs. Provides increased
deadband with 14-bit counters and Dead-band / Dead-band high-resolution registers are shadowed
•
High Resolution Extension available on ePWMxB outputs
Provides the ability to enable high-resolution period and duty cycle control on ePWMxB outputs. This is
discussed in more detail in the
HRPWM Reference Guide
.
•
Counter Compare Module Enhancements
ePWM Type 2 allows Interrupts and SOC events to be generated by additional counter compares
CMPC and CMPD.
•
Event Trigger Module Enhancements
Prescaling logic to issue interrupt requests and ADC start of conversion expanded upto every 15
events.Allows Software initialization of event counters on SYNC event.
•
Digital Compare Module Enhancements
Digital Compare Trip Select logic [DCTRIPSEL] has upto 12 external trip sources selected by GPTRIP
logic in addition to an ability to OR all of them (up to 14 [external & internal sources]) to create
respective DCxEVTs .
•
Simultaneous Writes to TBPRD and CMPx Registers
This feature allows writes to TBPRD, CMPA:CMPAHR, CMPB:CMPBHR, CMPC and CMPD of any
ePWM module to be tied to any other ePWM module, and also allows all ePWM modules to be tied to
a particular ePWM module if desired.
•
Shadow to Active Load on SYNC of TBPRD and CMP Registers
This feature supports simultaneous writes of TBPRD and CMPA/B/C/D registers.
An effective PWM peripheral must be able to generate complex pulse width waveforms with minimal CPU
overhead or intervention. It needs to be highly programmable and very flexible while being easy to
understand and use. The ePWM unit described here addresses these requirements by allocating all
needed timing and control resources on a per PWM channel basis. Cross coupling or sharing of resources
has been avoided; instead, the ePWM is built up from smaller single channel modules with separate
resources that can operate together as required to form a system. This modular approach results in an
orthogonal architecture and provides a more transparent view of the peripheral structure, helping users to
understand its operation quickly.