text: /* mbed Microcontroller Library
   * Copyright (c) 2006-2013 ARM Limited
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *     http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  #include "mbed_assert.h"
  #include "pwmout_api.h"
  
  #include "cmsis.h"
  #include "pinmap.h"
  #include "clk_freqs.h"
  #include "PeripheralPins.h"
  
  static float pwm_clock;
  
  void pwmout_init(pwmout_t *obj, PinName pin)
  {
      // determine the channel
      PWMName pwm = (PWMName)pinmap_peripheral(pin, PinMap_PWM);
      MBED_ASSERT(pwm != (PWMName)NC);
  
      uint32_t clkdiv = 0;
      float clkval;
  
  #if defined(TARGET_KL43Z)
      if (mcgirc_frequency()) {
          SIM->SOPT2 |= SIM_SOPT2_TPMSRC(3); // Clock source: MCGIRCLK
          clkval = mcgirc_frequency() / 1000000.0f;
      } else {
          SIM->SOPT2 |= SIM_SOPT2_TPMSRC(1); // Clock source: IRC48M
          clkval = CPU_INT_IRC_CLK_HZ / 1000000.0f;
      }
  #else
      if (mcgpllfll_frequency()) {
          SIM->SOPT2 |= SIM_SOPT2_TPMSRC(1); // Clock source: MCGFLLCLK or MCGPLLCLK
          clkval = mcgpllfll_frequency() / 1000000.0f;
      } else {
          SIM->SOPT2 |= SIM_SOPT2_TPMSRC(2); // Clock source: ExtOsc
          clkval = extosc_frequency() / 1000000.0f;
      }
  #endif
      while (clkval > 1) {
          clkdiv++;
          clkval /= 2.0;
          if (clkdiv == 7) {
              break;
          }
      }
  
      pwm_clock = clkval;
      unsigned int port  = (unsigned int)pin >> PORT_SHIFT;
      unsigned int tpm_n = (pwm >> TPM_SHIFT);
      unsigned int ch_n  = (pwm & 0xFF);
  
      SIM->SCGC5 |= 1 << (SIM_SCGC5_PORTA_SHIFT + port);
      SIM->SCGC6 |= 1 << (SIM_SCGC6_TPM0_SHIFT + tpm_n);
  
      TPM_Type *tpm = (TPM_Type *)(TPM0_BASE + 0x1000 * tpm_n);
      tpm->SC = TPM_SC_CMOD(1) | TPM_SC_PS(clkdiv); // (clock)MHz / clkdiv ~= (0.75)MHz
      tpm->CONTROLS[ch_n].CnSC = (TPM_CnSC_MSB_MASK | TPM_CnSC_ELSB_MASK); /* No Interrupts; High True pulses on Edge Aligned PWM */
  
      obj->CnV = &tpm->CONTROLS[ch_n].CnV;
      obj->MOD = &tpm->MOD;
      obj->CNT = &tpm->CNT;
  
      // default to 20ms: standard for servos, and fine for e.g. brightness control
      pwmout_period_ms(obj, 20);
      pwmout_write(obj, 0);
  
      // Wire pinout
      pinmap_pinout(pin, PinMap_PWM);
  }
  
  void pwmout_free(pwmout_t *obj) {}
  
  void pwmout_write(pwmout_t *obj, float value)
  {
      if (value < 0.0) {
          value = 0.0;
      } else if (value > 1.0) {
          value = 1.0;
      }
  
      *obj->CnV = (uint32_t)((float)(*obj->MOD + 1) * value);
      *obj->CNT = 0;
  }
  
  float pwmout_read(pwmout_t *obj)
  {
      float v = (float)(*obj->CnV) / (float)(*obj->MOD + 1);
      return (v > 1.0) ? (1.0) : (v);
  }
  
  void pwmout_period(pwmout_t *obj, float seconds)
  {
      pwmout_period_us(obj, seconds * 1000000.0f);
  }
  
  void pwmout_period_ms(pwmout_t *obj, int ms)
  {
      pwmout_period_us(obj, ms * 1000);
  }
  
  // Set the PWM period, keeping the duty cycle the same.
  void pwmout_period_us(pwmout_t *obj, int us)
  {
      float dc = pwmout_read(obj);
      *obj->MOD = (uint32_t)(pwm_clock * (float)us) - 1;
      pwmout_write(obj, dc);
  }
  
  int pwmout_read_period_us(pwmout_t *obj)
  {
      uint32_t pwm_period = 0;
      if (pwm_clock > 0) {
          pwm_period = ((*obj->MOD) + 1) / pwm_clock;
      }
      return pwm_period;
  }
  
  void pwmout_pulsewidth(pwmout_t *obj, float seconds)
  {
      pwmout_pulsewidth_us(obj, seconds * 1000000.0f);
  }
  
  void pwmout_pulsewidth_ms(pwmout_t *obj, int ms)
  {
      pwmout_pulsewidth_us(obj, ms * 1000);
  }
  
  void pwmout_pulsewidth_us(pwmout_t *obj, int us)
  {
      *obj->CnV = (uint32_t)(pwm_clock * (float)us);
  }
  
  int pwmout_read_pulsewidth_us(pwmout_t *obj)
  {
      uint32_t pwm_pulsewidth = 0;
      if (pwm_clock > 0) {
          pwm_pulsewidth = (*obj->CnV) / pwm_clock;
      }
      return pwm_pulsewidth;
  }
  
  const PinMap *pwmout_pinmap()
  {
      return PinMap_PWM;
  }
  