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RIOT/cpu/lpc2387/periph/pwm.c 3.76 KB
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  /*
   * Copyright (C) 2014 Freie Universitรคt Berlin
   *
   * This file is subject to the terms and conditions of the GNU Lesser General
   * Public License v2.1. See the file LICENSE in the top level directory for more
   * details.
   */
  
  /**
   * @ingroup     lpc2387
   * @{
   *
   * @file
   * @brief       CPU specific low-level PWM driver implementation for the LPC2387
   *
   * @author      Hauke Petersen <hauke.petersen@fu-berlin.de>
   *
   * @}
   */
  
  #include "bitarithm.h"
  #include "lpc2387.h"
  #include "periph_conf.h"
  
  /* guard file in case no PWM device is defined */
  #if (PWM_0_EN || PWM_1_EN)
  
  /* pull the PWM header inside the guards for now. Guards will be removed on
   * adapting this driver implementation... */
  #include "periph/pwm.h"
  
  /**
   * @note The PWM is always initialized with left-aligned mode.
   *
   * TODO: add center and right aligned modes
   */
  uint32_t pwm_init(pwm_t dev, pwm_mode_t mode, uint32_t freq, uint16_t res)
  {
      (void) mode; /* unused */
  
      switch (dev) {
  #if PWM_0_EN
          case PWM_0:
              /* select function PWM[3] for pins */
              PWM_0_PORT &= ~((3 << PWM_0_CH0_PIN * 2) |
                              (3 << PWM_0_CH1_PIN * 2) |
                              (3 << PWM_0_CH2_PIN * 2));
              PWM_0_PORT |= (PWM_0_FUNC << PWM_0_CH0_PIN * 2) |
                            (PWM_0_FUNC << PWM_0_CH1_PIN * 2) |
                            (PWM_0_FUNC << PWM_0_CH2_PIN * 2);
  
              /* power on PWM1 */
              pwm_poweron(dev);
  
              /* select PWM1 clock */
              PCLKSEL0 &= ~(BIT13);
              PCLKSEL0 |= (BIT12);
  
              /* reset PWM1s counter */
              PWM1TCR = BIT1;
  
              /* set prescaler */
              PWM1PR = (CLOCK_CORECLOCK / (freq * res)) - 1;
  
              /* set match register */
              PWM1MR0 = res;
              PWM_0_CH0_MR = 0;
              PWM_0_CH1_MR = 0;
              PWM_0_CH2_MR = 0;
  
              /* reset timer counter on MR0 match */
              PWM1MCR = BIT1;
  
              /* enable PWM1 channel 3, 4 and 5 */
              PWM1PCR = (1 << (8 + PWM_0_CH0)) | (1 << (8 + PWM_0_CH1)) | (1 << (8 + PWM_0_CH2));
  
              /* enable PWM1 timer in PWM mode */
              PWM1TCR = BIT0 + BIT3;
  
              /* update match registers */
              PWM1LER = BIT0 | (1 << PWM_0_CH0) | (1 << PWM_0_CH1) | (1 << PWM_0_CH2);
              break;
  #endif
          default:
              return 0;
      }
  
      return freq;
  }
  
  uint8_t pwm_channels(pwm_t dev)
  {
      if (dev == PWM_0) {
          return PWM_0_CHANNELS;
      }
      return 0;
  }
  
  void pwm_set(pwm_t dev, uint8_t channel, uint16_t value)
  {
      switch (dev) {
  #if PWM_0_EN
          case PWM_0:
              switch (channel) {
                  case 0:
                      PWM_0_CH0_MR = value;
                      PWM1LER |= (1 << PWM_0_CH0);
                      break;
                  case 1:
                      PWM_0_CH1_MR = value;
                      PWM1LER |= (1 << PWM_0_CH1);
                      break;
                  case 2:
                      PWM_0_CH2_MR = value;
                      PWM1LER |= (1 << PWM_0_CH2);
                      break;
                  default:
                      return;
                      break;
              }
              break;
  #endif
      }
  }
  
  void pwm_start(pwm_t dev)
  {
      switch (dev) {
  #if PWM_0_EN
          case PWM_0:
              PWM1TCR |= BIT0;
              break;
  #endif
      }
  }
  
  void pwm_stop(pwm_t dev)
  {
      switch (dev) {
  #if PWM_0_EN
          case PWM_0:
              PWM1TCR &= ~(BIT0);
              break;
  #endif
      }
  }
  
  void pwm_poweron(pwm_t dev)
  {
      switch (dev) {
  #if PWM_0_EN
          case PWM_0:
              PCONP |= PCPWM1;
              break;
  #endif
      }
  }
  
  void pwm_poweroff(pwm_t dev)
  {
      switch (dev) {
  #if PWM_0_EN
          case PWM_0:
              PCONP &= ~(PCPWM1);
              break;
  #endif
      }
  }
  
  #endif /* (PWM_0_EN || PWM_1_EN) */