boards/evkmimx8mq/driver_examples/pwm/pwm.c

/*
 * Copyright (c) 2015, Freescale Semiconductor, Inc.
 * Copyright 2016-2017 NXP
 * All rights reserved.
 *
 * SPDX-License-Identifier: BSD-3-Clause
 */

#include "fsl_debug_console.h"
#include "board.h"
#include "fsl_pwm.h"

#include "pin_mux.h"
#include "clock_config.h"
#include "fsl_common.h"
/*******************************************************************************
 * Definitions
 ******************************************************************************/
#define DEMO_PWM_BASEADDR   PWM4
#define DEMO_PWM_IRQn       PWM4_IRQn
#define DEMO_PWM_IRQHandler PWM4_IRQHandler
/*! @brief PWM period value. PWMO (Hz) = PCLK(Hz) / (period +2) */
#define PWM_PERIOD_VALUE 30

/*******************************************************************************
 * Prototypes
 ******************************************************************************/

/*******************************************************************************
 * Variables
 ******************************************************************************/
volatile uint32_t pwmDutycycle = 0U;
volatile bool pwmDutyUp        = true; /* Indicate PWM Duty cycle is increase or decrease */

/*******************************************************************************
 * Code
 ******************************************************************************/

void DEMO_PWM_IRQHandler(void)
{
    /* Gets interrupt kPWM_FIFOEmptyFlag */
    if (PWM_GetStatusFlags(DEMO_PWM_BASEADDR) & kPWM_FIFOEmptyFlag)
    {
        if (pwmDutyUp)
        {
            /* Increase duty cycle until it reach limited value. */
            if (++pwmDutycycle > PWM_PERIOD_VALUE)
            {
                pwmDutycycle = PWM_PERIOD_VALUE;
                pwmDutyUp    = false;
            }
        }
        else
        {
            /* Decrease duty cycle until it reach limited value. */
            if (--pwmDutycycle == 0U)
            {
                pwmDutyUp = true;
            }
        }
        /* Write duty cycle to PWM sample register.  */
        PWM_SetSampleValue(DEMO_PWM_BASEADDR, pwmDutycycle);
        /* Clear kPWM_FIFOEmptyFlag */
        PWM_clearStatusFlags(DEMO_PWM_BASEADDR, kPWM_FIFOEmptyFlag);
    }
    SDK_ISR_EXIT_BARRIER;
}

/*!
 * @brief Main function
 */
int main(void)
{
    pwm_config_t pwmConfig;

    /* Board pin, clock, debug console init */
    /* Board specific RDC settings */
    BOARD_RdcInit();

    BOARD_InitPins();
    BOARD_BootClockRUN();
    BOARD_InitDebugConsole();
    BOARD_InitMemory();

    PRINTF("\r\nPWM driver example.\r\n");

    /*!
     * config->enableStopMode = false;
     * config->enableDozeMode = false;
     * config->enableWaitMode = false;
     * config->enableDebugMode = false;
     * config->clockSource = kPWM_LowFrequencyClock;
     * config->prescale = 0U;
     * config->outputConfig = kPWM_SetAtRolloverAndClearAtcomparison;
     * config->fifoWater = kPWM_FIFOWaterMark_2;
     * config->sampleRepeat = kPWM_EachSampleOnce;
     * config->byteSwap = kPWM_ByteNoSwap;
     * config->halfWordSwap = kPWM_HalfWordNoSwap;
     */
    PWM_GetDefaultConfig(&pwmConfig);

    /* Initialize PWM module */
    PWM_Init(DEMO_PWM_BASEADDR, &pwmConfig);

    /* Enable FIFO empty interrupt */
    PWM_EnableInterrupts(DEMO_PWM_BASEADDR, kPWM_FIFOEmptyInterruptEnable);

    /* Three initial samples be written to the PWM Sample Register */
    for (pwmDutycycle = 0u; pwmDutycycle < 3; pwmDutycycle++)
    {
        PWM_SetSampleValue(DEMO_PWM_BASEADDR, pwmDutycycle);
    }

    /* Check and Clear interrupt status flags */
    if (PWM_GetStatusFlags(DEMO_PWM_BASEADDR))
    {
        PWM_clearStatusFlags(DEMO_PWM_BASEADDR,
                             kPWM_FIFOEmptyFlag | kPWM_RolloverFlag | kPWM_CompareFlag | kPWM_FIFOWriteErrorFlag);
    }

    /* Write the period to the PWM Period Register */
    PWM_SetPeriodValue(DEMO_PWM_BASEADDR, PWM_PERIOD_VALUE);

    /* Enable PWM interrupt request */
    EnableIRQ(DEMO_PWM_IRQn);

    PWM_StartTimer(DEMO_PWM_BASEADDR);

    while (1)
    {
    }
}