ChibiOS/os/hal/platforms/STM32/pwm_lld.c

/*
    ChibiOS/RT - Copyright (C) 2006-2007 Giovanni Di Sirio.

    This file is part of ChibiOS/RT.

    ChibiOS/RT is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
    the Free Software Foundation; either version 3 of the License, or
    (at your option) any later version.

    ChibiOS/RT is distributed in the hope that it will be useful,
    but WITHOUT ANY WARRANTY; without even the implied warranty of
    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
    GNU General Public License for more details.

    You should have received a copy of the GNU General Public License
    along with this program.  If not, see <http://www.gnu.org/licenses/>.
*/

/**
 * @file STM32/pwm_lld.c
 * @brief STM32 PWM subsystem low level driver header.
 * @addtogroup STM32_PWM
 * @{
 */

#include "ch.h"
#include "hal.h"

#if CH_HAL_USE_PWM || defined(__DOXYGEN__)

/** @brief PWM1 driver identifier.*/
#if defined(USE_STM32_PWM1) || defined(__DOXYGEN__)
PWMDriver PWMD1;
#endif

/*===========================================================================*/
/* Low Level Driver exported variables.                                      */
/*===========================================================================*/

/*===========================================================================*/
/* Low Level Driver local variables.                                         */
/*===========================================================================*/

/*===========================================================================*/
/* Low Level Driver local functions.                                         */
/*===========================================================================*/

/**
 * @brief Stops all channels.
 *
 * @param[in] pwmp pointer to a @p PWMDriver object
 */
void stop_channels(PWMDriver *pwmp) {

  pwmp->pd_enabled_channels = 0;            /* All channels disabled.       */
  pwmp->pd_tim->CCER = 0;                   /* Outputs disabled.            */
  pwmp->pd_tim->CCMR1 = 0;                  /* Channels 1 and 2 frozen.     */
  pwmp->pd_tim->CCMR2 = 0;                  /* Channels 3 and 4 frozen.     */
}

/*===========================================================================*/
/* Low Level Driver interrupt handlers.                                      */
/*===========================================================================*/

#if USE_STM32_PWM1
/**
 * @brief TIM1 update interrupt handler.
 * @note It is assumed that this interrupt is only activated if the callback
 *       pointer is not equal to @p NULL in order to not perform an extra
 *       check in a potentially critical interrupt handler.
 */
CH_IRQ_HANDLER(VectorA4) {

  CH_IRQ_PROLOGUE();

  PWMD1.pd_config->pc_callback();

  CH_IRQ_EPILOGUE();
}

/**
 * @brief TIM1 compare interrupt handler.
 * @note It is assumed that the various sources are only activated if the
 *       associated callback pointer is not equal to @p NULL in order to not
 *       perform an extra check in a potentially critical interrupt handler.
 */
CH_IRQ_HANDLER(VectorAC) {
  uint16_t sr;

  CH_IRQ_PROLOGUE();

  sr = TIM1->SR;
  TIM1->SR &= ~(TIM_SR_CC1IF | TIM_SR_CC2IF | TIM_SR_CC3IF | TIM_SR_CC4IF);
  if ((sr & TIM_SR_CC1IF) != 0)
    PWMD1.pd_channel_configs[0]->pcc_callback();
  if ((sr & TIM_SR_CC2IF) != 0)
    PWMD1.pd_channel_configs[1]->pcc_callback();
  if ((sr & TIM_SR_CC3IF) != 0)
    PWMD1.pd_channel_configs[2]->pcc_callback();
  if ((sr & TIM_SR_CC4IF) != 0)
    PWMD1.pd_channel_configs[3]->pcc_callback();
  CH_IRQ_EPILOGUE();
}
#endif /* USE_STM32_PWM1 */

/*===========================================================================*/
/* Low Level Driver exported functions.                                      */
/*===========================================================================*/

/**
 * @brief Low level PWM driver initialization.
 */
void pwm_lld_init(void) {

#if USE_STM32_PWM1
  /* TIM1 reset, ensures reset state in order to avoid trouble with JTAGs.*/
  RCC->APB2RSTR = RCC_APB2RSTR_TIM1RST;
  RCC->APB2RSTR = 0;

  /* Driver initialization.*/
  pwmObjectInit(&PWMD1);
  PWMD1.pd_enabled_channels = 0;
  PWMD1.pd_tim = TIM1;
#endif

}

/**
 * @brief Configures and activates the PWM peripheral.
 *
 * @param[in] pwmp pointer to a @p PWMDriver object
 */
void pwm_lld_start(PWMDriver *pwmp) {

  if (pwmp->pd_state == PWM_STOP) {
    /* Clock activation.*/
#if USE_STM32_PWM1
    if (&PWMD1 == pwmp) {
      NVICEnableVector(TIM1_UP_IRQn, STM32_PWM1_IRQ_PRIORITY);
      NVICEnableVector(TIM1_CC_IRQn, STM32_PWM1_IRQ_PRIORITY);
      RCC->APB2ENR |= RCC_APB2ENR_TIM1EN;
    }
#endif
  }
  /* Reset channels.*/
  stop_channels(pwmp);

  /* Configuration or reconfiguration.*/
  pwmp->pd_tim->CR1 = pwmp->pd_config->pc_cr1;
  pwmp->pd_tim->CR2 = pwmp->pd_config->pc_cr2;
  pwmp->pd_tim->PSC = pwmp->pd_config->pc_psc;
  pwmp->pd_tim->ARR = pwmp->pd_config->pc_arr;
  pwmp->pd_tim->CNT = 0;
  pwmp->pd_tim->EGR = TIM_EGR_UG;           /* Update event.                */
  pwmp->pd_tim->SR = 0;                     /* Clear pending IRQs.          */
  if (pwmp->pd_config->pc_callback == NULL)
    pwmp->pd_tim->DIER = 0;                 /* No IRQs.                     */
  else
    pwmp->pd_tim->DIER = TIM_DIER_UIE;      /* IRQ on update event.         */
  pwmp->pd_tim->CR1 |= TIM_CR1_CEN;         /* Starts the timer.            */
}

/**
 * @brief Deactivates the PWM peripheral.
 *
 * @param[in] pwmp pointer to a @p PWMDriver object
 */
void pwm_lld_stop(PWMDriver *pwmp) {

  /* If in ready state then disables the PWM clock.*/
  if (pwmp->pd_state == PWM_READY) {
#if USE_STM32_PWM1
    if (&PWMD1 == pwmp) {
      NVICDisableVector(TIM1_UP_IRQn);
      NVICDisableVector(TIM1_CC_IRQn);
      RCC->APB2ENR &= ~RCC_APB2ENR_TIM1EN;
    }
#endif
  }

  stop_channels(pwmp);
  pwmp->pd_tim->CR1 = 0;
  pwmp->pd_tim->DIER = 0;
}

/**
 * @brief Determines whatever the PWM channel is already enabled.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] channel   PWM channel identifier
 *
 * @return The PWM channel status.
 * @retval FALSE the channel is not enabled.
 * @retval TRUE the channel is enabled.
 */
bool_t pwm_lld_is_enabled(PWMDriver *pwmp, pwmchannel_t channel) {

  return (pwmp->pd_enabled_channels & (1 << channel)) != 0;
}

/**
 * @brief Setups a PWM channel.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] channel   PWM channel identifier
 */
void pwm_lld_setup_channel(PWMDriver *pwmp, pwmchannel_t channel) {

}

/**
 * @brief Enables a PWM channel.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] channel   PWM channel identifier
 * @param[in] width     PWM pulse width as clock pulses number
 */
void pwm_lld_enable_channel(PWMDriver *pwmp,
                            pwmchannel_t channel,
                            pwmcnt_t width) {

  pwmp->pd_enabled_channels |= (1 << channel);
}

/**
 * @brief Disables a PWM channel.
 * @details The channel is disabled and its output line returned to the
 *          idle state.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] channel   PWM channel identifier
 */
void pwm_lld_disable_channel(PWMDriver *pwmp, pwmchannel_t channel) {

  pwmp->pd_enabled_channels &= ~(1 << channel);
}

#endif /* CH_HAL_USE_PWM */

/** @} */