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[/] [neorv32/] [trunk/] [sw/] [lib/] [source/] [neorv32_pwm.c] - Blame information for rev 61

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// #################################################################################################
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// # << NEORV32: neorv32_pwm.c - Pulse Width Modulation Controller (PWM) HW Driver >>              #
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// # ********************************************************************************************* #
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// # BSD 3-Clause License                                                                          #
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// #                                                                                               #
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// # Copyright (c) 2021, Stephan Nolting. All rights reserved.                                     #
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// #                                                                                               #
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// # Redistribution and use in source and binary forms, with or without modification, are          #
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// # permitted provided that the following conditions are met:                                     #
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// #                                                                                               #
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// # 1. Redistributions of source code must retain the above copyright notice, this list of        #
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// #    conditions and the following disclaimer.                                                   #
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// #                                                                                               #
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// # 2. Redistributions in binary form must reproduce the above copyright notice, this list of     #
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// #    conditions and the following disclaimer in the documentation and/or other materials        #
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// #    provided with the distribution.                                                            #
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// #                                                                                               #
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// # 3. Neither the name of the copyright holder nor the names of its contributors may be used to  #
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// #    endorse or promote products derived from this software without specific prior written      #
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// #    permission.                                                                                #
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// #                                                                                               #
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// # THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS   #
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// # OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF               #
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// # MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE    #
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// # COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,     #
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// # EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE #
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// # GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED    #
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// # AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING     #
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// # NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED  #
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// # OF THE POSSIBILITY OF SUCH DAMAGE.                                                            #
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// # ********************************************************************************************* #
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// # The NEORV32 Processor - https://github.com/stnolting/neorv32              (c) Stephan Nolting #
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// #################################################################################################
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/**********************************************************************//**
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 * @file neorv32_pwm.c
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 * @author Stephan Nolting
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 * @brief Pulse-Width Modulation Controller (PWM) HW driver source file.
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 *
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 * @note These functions should only be used if the PWM unit was synthesized (IO_PWM_EN = true).
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 **************************************************************************/
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#include "neorv32.h"
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#include "neorv32_pwm.h"
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/**********************************************************************//**
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 * Check if PWM unit was synthesized.
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 *
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 * @return 0 if PWM was not synthesized, 1 if PWM is available.
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 **************************************************************************/
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int neorv32_pwm_available(void) {
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  if (SYSINFO_FEATURES & (1 << SYSINFO_FEATURES_IO_PWM)) {
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    return 1;
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  }
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  else {
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    return 0;
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  }
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}
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/**********************************************************************//**
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 * Enable and configure pulse width modulation controller. The PWM control register bits are listed in #NEORV32_PWM_CT_enum.
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 *
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 * @param[in] prsc Clock prescaler select (0..7). See #NEORV32_CLOCK_PRSC_enum.
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 **************************************************************************/
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void neorv32_pwm_setup(uint8_t prsc) {
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  PWM_CT = 0; // reset
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  uint32_t ct_enable = 1;
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  ct_enable = ct_enable << PWM_CT_EN;
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  uint32_t ct_prsc = (uint32_t)(prsc & 0x07);
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  ct_prsc = ct_prsc << PWM_CT_PRSC0;
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  PWM_CT = ct_enable | ct_prsc;
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}
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/**********************************************************************//**
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 * Disable pulse width modulation controller.
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 **************************************************************************/
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void neorv32_pwm_disable(void) {
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  PWM_CT &= ~((uint32_t)(1 << PWM_CT_EN));
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}
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/**********************************************************************//**
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 * Enable pulse width modulation controller.
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 **************************************************************************/
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void neorv32_pwm_enable(void) {
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  PWM_CT |= ((uint32_t)(1 << PWM_CT_EN));
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}
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/**********************************************************************//**
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 * Get number of implemented channels.
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 * @warning This function will override all duty cycle configuration registers.
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 *
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 * @return Number of implemented channels.
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 **************************************************************************/
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int neorv32_pmw_get_num_channels(void) {
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  neorv32_pwm_disable();
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  uint8_t index = 0;
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  uint8_t cnt = 0;
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  for (index=0; index<60; index++) {
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    neorv32_pwm_set(index, 1);
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    cnt += neorv32_pwm_get(index);
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  }
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  return (int)cnt;
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}
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/**********************************************************************//**
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 * Set duty cycle for channel.
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 *
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 * @param[in] channel Channel select (0..59).
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 * @param[in] duty Duty cycle (0..255).
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 **************************************************************************/
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void neorv32_pwm_set(uint8_t channel, uint8_t duty) {
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  if (channel > 59) {
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    return; // out-of-range
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  }
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  // compute duty-cycle offset
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  uint32_t reg_offset  = (uint32_t)(channel / 4);
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  uint8_t  byte_offset = channel % 4;
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  // read-modify-write
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  uint32_t duty_mask = 0xff;
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  uint32_t duty_new  = (uint32_t)duty;
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  duty_mask = duty_mask << (byte_offset * 8);
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  duty_new  = duty_new  << (byte_offset * 8);
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  uint32_t duty_cycle = (*(IO_REG32 (&PWM_DUTY0 + reg_offset)));
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  duty_cycle &= ~duty_mask; // clear previous duty cycle
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  duty_cycle |= duty_new; // set new duty cycle
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  (*(IO_REG32 (&PWM_DUTY0 + reg_offset))) = duty_cycle;
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}
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/**********************************************************************//**
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 * Get duty cycle from channel.
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 *
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 * @param[in] channel Channel select (0..59).
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 * @return Duty cycle (0..255) of channel 'channel'.
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 **************************************************************************/
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uint8_t neorv32_pwm_get(uint8_t channel) {
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  if (channel > 59) {
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    return 0; // out-of-range
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  }
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  // compute duty-cycle offset
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  uint32_t reg_offset  = (uint32_t)(channel / 4);
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  uint8_t  byte_offset = channel % 4;
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  // read
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  uint32_t tmp = (*(IO_REG32 (&PWM_DUTY0 + reg_offset)));
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  tmp = tmp >> ((byte_offset * 8));
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  return (uint8_t)tmp;
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}

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