tinySA/os/hal/include/pwm.h

/*
    ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
                 2011 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    pwm.h
 * @brief   PWM Driver macros and structures.
 *
 * @addtogroup PWM
 * @{
 */

#ifndef _PWM_H_
#define _PWM_H_

#if HAL_USE_PWM || defined(__DOXYGEN__)

/*===========================================================================*/
/* Driver constants.                                                         */
/*===========================================================================*/

/**
 * @brief   Standard output modes mask.
 */
#define PWM_OUTPUT_MASK                         0x0F

/**
 * @brief   Output not driven, callback only.
 */
#define PWM_OUTPUT_DISABLED                     0x00

/**
 * @brief   Positive PWM logic, active is logic level one.
 */
#define PWM_OUTPUT_ACTIVE_HIGH                  0x01

/**
 * @brief   Inverse PWM logic, active is logic level zero.
 */
#define PWM_OUTPUT_ACTIVE_LOW                   0x02

/*===========================================================================*/
/* Driver pre-compile time settings.                                         */
/*===========================================================================*/

/*===========================================================================*/
/* Derived constants and error checks.                                       */
/*===========================================================================*/

/*===========================================================================*/
/* Driver data structures and types.                                         */
/*===========================================================================*/

/**
 * @brief   Driver state machine possible states.
 */
typedef enum {
  PWM_UNINIT = 0,                   /**< Not initialized.                   */
  PWM_STOP = 1,                     /**< Stopped.                           */
  PWM_READY = 2,                    /**< Ready.                             */
} pwmstate_t;

/**
 * @brief   Type of a structure representing a PWM driver.
 */
typedef struct PWMDriver PWMDriver;

/**
 * @brief   PWM notification callback type.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 */
typedef void (*pwmcallback_t)(PWMDriver *pwmp);

#include "pwm_lld.h"

/*===========================================================================*/
/* Driver macros.                                                            */
/*===========================================================================*/

/**
 * @brief   Converts from fraction to pulse width.
 * @note    Be careful with rounding errors, this is integer math not magic.
 *          You can specify tenths of thousandth but make sure you have the
 *          proper hardware resolution by carefully choosing the clock source
 *          and prescaler settings, see @p PWM_COMPUTE_PSC.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] denominator denominator of the fraction
 * @param[in] numerator numerator of the fraction
 * @return              The pulse width to be passed to @p pwmEnableChannel().
 *
 * @api
 */
#define PWM_FRACTION_TO_WIDTH(pwmp, denominator, numerator)                 \
  ((uint16_t)((((uint32_t)(pwmp)->period) *                                 \
               (uint32_t)(numerator)) / (uint32_t)(denominator)))

/**
 * @brief   Converts from degrees to pulse width.
 * @note    Be careful with rounding errors, this is integer math not magic.
 *          You can specify hundredths of degrees but make sure you have the
 *          proper hardware resolution by carefully choosing the clock source
 *          and prescaler settings, see @p PWM_COMPUTE_PSC.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] degrees   degrees as an integer between 0 and 36000
 * @return              The pulse width to be passed to @p pwmEnableChannel().
 *
 * @api
 */
#define PWM_DEGREES_TO_WIDTH(pwmp, degrees)                                 \
  PWM_FRACTION_TO_WIDTH(pwmp, 36000, degrees)

/**
 * @brief   Converts from percentage to pulse width.
 * @note    Be careful with rounding errors, this is integer math not magic.
 *          You can specify tenths of thousandth but make sure you have the
 *          proper hardware resolution by carefully choosing the clock source
 *          and prescaler settings, see @p PWM_COMPUTE_PSC.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] percentage percentage as an integer between 0 and 10000
 * @return              The pulse width to be passed to @p pwmEnableChannel().
 *
 * @api
 */
#define PWM_PERCENTAGE_TO_WIDTH(pwmp, percentage)                           \
  PWM_FRACTION_TO_WIDTH(pwmp, 10000, percentage)

/**
 * @brief   Changes the period the PWM peripheral.
 * @details This function changes the period of a PWM unit that has already
 *          been activated using @p pwmStart().
 * @pre     The PWM unit must have been activated using @p pwmStart().
 * @post    The PWM unit period is changed to the new value.
 * @note    If a period is specified that is shorter than the pulse width
 *          programmed in one of the channels then the behavior is not
 *          guaranteed.
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] period    new cycle time in ticks
 *
 * @iclass
 */
#define pwmChangePeriodI(pwmp, period) {                                    \
  (pwmp)->period = (period);                                                \
  pwm_lld_change_period(pwmp, period);                                      \
}

/**
 * @brief   Enables a PWM channel.
 * @pre     The PWM unit must have been activated using @p pwmStart().
 * @post    The channel is active using the specified configuration.
 * @note    Depending on the hardware implementation this function has
 *          effect starting on the next cycle (recommended implementation)
 *          or immediately (fallback implementation).
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] channel   PWM channel identifier (0...PWM_CHANNELS-1)
 * @param[in] width     PWM pulse width as clock pulses number
 *
 * @iclass
 */
#define pwmEnableChannelI(pwmp, channel, width)                             \
  pwm_lld_enable_channel(pwmp, channel, width)

/**
 * @brief   Disables a PWM channel.
 * @pre     The PWM unit must have been activated using @p pwmStart().
 * @post    The channel is disabled and its output line returned to the
 *          idle state.
 * @note    Depending on the hardware implementation this function has
 *          effect starting on the next cycle (recommended implementation)
 *          or immediately (fallback implementation).
 *
 * @param[in] pwmp      pointer to a @p PWMDriver object
 * @param[in] channel   PWM channel identifier (0...PWM_CHANNELS-1)
 *
 * @iclass
 */
#define pwmDisableChannelI(pwmp, channel)                                   \
  pwm_lld_disable_channel(pwmp, channel)

/*===========================================================================*/
/* External declarations.                                                    */
/*===========================================================================*/

#ifdef __cplusplus
extern "C" {
#endif
  void pwmInit(void);
  void pwmObjectInit(PWMDriver *pwmp);
  void pwmStart(PWMDriver *pwmp, const PWMConfig *config);
  void pwmStop(PWMDriver *pwmp);
  void pwmChangePeriod(PWMDriver *pwmp, pwmcnt_t period);
  void pwmEnableChannel(PWMDriver *pwmp,
                        pwmchannel_t channel,
                        pwmcnt_t width);
  void pwmDisableChannel(PWMDriver *pwmp, pwmchannel_t channel);
#ifdef __cplusplus
}
#endif

#endif /* HAL_USE_PWM */

#endif /* _PWM_H_ */

/** @} */