76 lines
2.5 KiB
C
76 lines
2.5 KiB
C
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/*
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* Copyright (C) 2023 Texas Instruments Incorporated
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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*
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* Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the
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* distribution.
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*
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* Neither the name of Texas Instruments Incorporated nor the names of
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* its contributors may be used to endorse or promote products derived
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* from this software without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
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* A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
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* OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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* SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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* LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
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* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
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* (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
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* OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*/
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#include "epwm_mod.h"
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#include <stdint.h>
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#include <math.h>
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/* Min / max output amplitude.
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Waveform amplitude values beyond these thresholds are saturated. */
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#define VREF_MAX ( 1.0f )
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#define VREF_MIN ( -1.0f )
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/* Compute Duty Cycle & CMPx given Vref & EPWM period */
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void computeCmpx(
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float Vref,
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uint32_t epwmPrdVal,
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float *pEpwmDutyCycle,
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uint16_t *pEpwmCmpVal
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)
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{
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float dc_f;
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float cmp_f;
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uint16_t cmp;
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if (Vref >= VREF_MAX) {
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/* 100% duty cycle */
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dc_f = 1.0;
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}
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else if (Vref <= VREF_MIN) {
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/* 0% duty cycle */
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dc_f = 0.0;
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}
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else {
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/* compute Duty Cycle */
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dc_f = 0.5*(Vref + 1.0);
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}
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/* compute CMPx */
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cmp_f = (1.0 - dc_f)*epwmPrdVal; /* up-down count */
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cmp = (uint16_t)roundf(cmp_f);
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*pEpwmDutyCycle = dc_f;
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*pEpwmCmpVal = cmp;
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}
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