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Operational Description of HRPWM

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SPRUI07–March 2020

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High-Resolution Pulse Width Modulator (HRPWM)

To use the HRPWM feature of the ePWMs, it is recommended that the SFO functions be used as

described here.

Step 1. Add Include Files

The SFO.h file needs to be included as follows. This include file is mandatory while using the SFO library

function.

Example 4-1. A Sample of How to Add Include Files

#include "device280x_Device.h" // device280x Headerfile

#include "device280x_EPWM_defines.h" // init defines

#include "SFO.h" // SFO lib functions (needed for HRPWM)

Step 2. Element Declaration

Declare a 5-element array of integer variables as follows:

Example 4-2. Declaring an Element

int MEP_ScaleFactor[5] = {0,0,0,0,0}; // Scale factor values for ePWM1-4

int MEP_ScaleFactor1, MEP_ScaleFactor2, MEP_ScaleFactor3, MEP_ScaleFactor4 // Not required by library

volatile struct EPWM_REGS *ePWM[] = {0, &EPwm1Regs, &EPwm2Regs, &EPwm3Regs, &EPwm4Regs};

Step 3. MEP_ScaleFactor Initialization

After power up, the SFO_MepEn(n) function needs a starting Scale Factor value. This value can be

conveniently determined by using one of the ePWM modules to run the SFO_MepDis(n) function prior to

configuring its PWM outputs for the application. SFO_MepDis(n) function does not require a starting Scale

Factor value.

As part of the one-time initialization code, include the following:

Example 4-3. Initializing With a Scale Factor Value

// MEP_ScaleFactor variables initialized using function SFO_MepDis

while (MEP_ScaleFactor[1] == 0) SFO_MepDis(1); //SFO for HRPWM1

while (MEP_ScaleFactor[2] == 0) SFO_MepDis(2); //SFO for HRPWM2

while (MEP_ScaleFactor[3] == 0) SFO_MepDis(3); //SFO for HRPWM3

while (MEP_ScaleFactor[4] == 0) SFO_MepDis(4); //SFO for HRPWM4

// Initialize a common seed variable MEP_ScaleFactor[0] // required for all SFO functions

MEP_ScaleFactor[0] = MEP_ScaleFactor[1]; // Common variable for SFOMepEn(n) function

Texas Instruments TMS320 2833 Series User Manual

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