Subversion Repositories neorv32

// #################################################################################################

// # << NEORV32: neorv32_pwm.c - Pulse Width Modulation Controller (PWM) HW Driver >>              #

// # ********************************************************************************************* #

// # BSD 3-Clause License                                                                          #

// #                                                                                               #

// # Copyright (c) 2021, Stephan Nolting. All rights reserved.                                     #

// #                                                                                               #

// # Redistribution and use in source and binary forms, with or without modification, are          #

// # permitted provided that the following conditions are met:                                     #

// #                                                                                               #

// # 1. Redistributions of source code must retain the above copyright notice, this list of        #

// #    conditions and the following disclaimer.                                                   #

// #                                                                                               #

// # 2. Redistributions in binary form must reproduce the above copyright notice, this list of     #

// #    conditions and the following disclaimer in the documentation and/or other materials        #

// #    provided with the distribution.                                                            #

// #                                                                                               #

// # 3. Neither the name of the copyright holder nor the names of its contributors may be used to  #

// #    endorse or promote products derived from this software without specific prior written      #

// #    permission.                                                                                #

// #                                                                                               #

// # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS   #

// # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF               #

// # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE    #

// # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,     #

// # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE #

// # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED    #

// # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING     #

// # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED  #

// # OF THE POSSIBILITY OF SUCH DAMAGE.                                                            #

// # ********************************************************************************************* #

// # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #

// #################################################################################################

/**********************************************************************//**

 * @file neorv32_pwm.c

 * @author Stephan Nolting

 * @brief Pulse-Width Modulation Controller (PWM) HW driver source file.

 *

 * @note These functions should only be used if the PWM unit was synthesized (IO_PWM_EN = true).

 **************************************************************************/

#include "neorv32.h"

#include "neorv32_pwm.h"

/**********************************************************************//**

 * Check if PWM unit was synthesized.

 *

 * @return 0 if PWM was not synthesized, 1 if PWM is available.

 **************************************************************************/

int neorv32_pwm_available(void) {

  if (SYSINFO_FEATURES & (1 << SYSINFO_FEATURES_IO_PWM)) {

    return 1;

  }

  else {

    return 0;

  }

}

/**********************************************************************//**

 * Enable and configure pulse width modulation controller. The PWM control register bits are listed in #NEORV32_PWM_CT_enum.

 *

 * @param[in] prsc Clock prescaler select (0..7). See #NEORV32_CLOCK_PRSC_enum.

 **************************************************************************/

void neorv32_pwm_setup(uint8_t prsc) {

  PWM_CT = 0; // reset

  uint32_t ct_enable = 1;

  ct_enable = ct_enable << PWM_CT_EN;

  uint32_t ct_prsc = (uint32_t)(prsc & 0x07);

  ct_prsc = ct_prsc << PWM_CT_PRSC0;

  PWM_CT = ct_enable | ct_prsc;

}

/**********************************************************************//**

 * Disable pulse width modulation controller.

 **************************************************************************/

void neorv32_pwm_disable(void) {

  PWM_CT &= ~((uint32_t)(1 << PWM_CT_EN));

}

/**********************************************************************//**

 * Enable pulse width modulation controller.

 **************************************************************************/

void neorv32_pwm_enable(void) {

  PWM_CT |= ((uint32_t)(1 << PWM_CT_EN));

}

/**********************************************************************//**

 * Get number of implemented channels.

 * @warning This function will override all duty cycle configuration registers.

 *

 * @return Number of implemented channels.

 **************************************************************************/

int neorv32_pmw_get_num_channels(void) {

  neorv32_pwm_disable();

  uint8_t index = 0;

  uint8_t cnt = 0;

  for (index=0; index<60; index++) {

    neorv32_pwm_set(index, 1);

    cnt += neorv32_pwm_get(index);

  }

  return (int)cnt;

}

/**********************************************************************//**

 * Set duty cycle for channel.

 *

 * @param[in] channel Channel select (0..59).

 * @param[in] duty Duty cycle (0..255).

 **************************************************************************/

void neorv32_pwm_set(uint8_t channel, uint8_t duty) {

  if (channel > 59) {

    return; // out-of-range

  }

  // compute duty-cycle offset

  uint32_t reg_offset  = (uint32_t)(channel / 4);

  uint8_t  byte_offset = channel % 4;

  // read-modify-write

  uint32_t duty_mask = 0xff;

  uint32_t duty_new  = (uint32_t)duty;

  duty_mask = duty_mask << (byte_offset * 8);

  duty_new  = duty_new  << (byte_offset * 8);

  uint32_t duty_cycle = (*(IO_REG32 (&PWM_DUTY0 + reg_offset)));

  duty_cycle &= ~duty_mask; // clear previous duty cycle

  duty_cycle |= duty_new; // set new duty cycle

  (*(IO_REG32 (&PWM_DUTY0 + reg_offset))) = duty_cycle;

}

/**********************************************************************//**

 * Get duty cycle from channel.

 *

 * @param[in] channel Channel select (0..59).

 * @return Duty cycle (0..255) of channel 'channel'.

 **************************************************************************/

uint8_t neorv32_pwm_get(uint8_t channel) {

  if (channel > 59) {

    return 0; // out-of-range

  }

  // compute duty-cycle offset

  uint32_t reg_offset  = (uint32_t)(channel / 4);

  uint8_t  byte_offset = channel % 4;

  // read

  uint32_t tmp = (*(IO_REG32 (&PWM_DUTY0 + reg_offset)));

  tmp = tmp >> ((byte_offset * 8));

  return (uint8_t)tmp;

}