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RIOT/cpu/samd21/periph/timer.c 9.06 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     driver_periph
   * @{
   *
   * @file
   * @brief       Low-level timer driver implementation
   *
   * @author      Thomas Eichinger <thomas.eichinger@fu-berlin.de>
   *
   * @}
   */
  
  #include <stdlib.h>
  #include <stdio.h>
  
  #include "board.h"
  #include "cpu.h"
  
  #include "periph/timer.h"
  #include "periph_conf.h"
  
  #define ENABLE_DEBUG    (0)
  #include "debug.h"
  
  /**
   * @brief Timer state memory
   */
  static timer_isr_ctx_t config[TIMER_NUMOF];
  
  
  /**
   * @brief Setup the given timer
   */
  int timer_init(tim_t dev, unsigned long freq, timer_cb_t cb, void *arg)
  {
      /* at the moment, the timer can only run at 1MHz */
      if (freq != 1000000ul) {
          return -1;
      }
  
  /* select the clock generator depending on the main clock source:
   * GCLK0 (1MHz) if we use the internal 8MHz oscillator
   * GCLK1 (8MHz) if we use the PLL */
  #if CLOCK_USE_PLL
      /* configure GCLK1 (configured to 1MHz) to feed TC3, TC4 and TC5 */;
      GCLK->CLKCTRL.reg = (uint16_t)((GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK1 | (TC3_GCLK_ID << GCLK_CLKCTRL_ID_Pos)));
      while (GCLK->STATUS.bit.SYNCBUSY) {}
      /* TC4 and TC5 share the same channel */
      GCLK->CLKCTRL.reg = (uint16_t)((GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK1 | (TC4_GCLK_ID << GCLK_CLKCTRL_ID_Pos)));
  #else
      /* configure GCLK0 to feed TC3, TC4 and TC5 */;
      GCLK->CLKCTRL.reg = (uint16_t)((GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | (TC3_GCLK_ID << GCLK_CLKCTRL_ID_Pos)));
      /* TC4 and TC5 share the same channel */
      GCLK->CLKCTRL.reg = (uint16_t)((GCLK_CLKCTRL_CLKEN | GCLK_CLKCTRL_GEN_GCLK0 | (TC4_GCLK_ID << GCLK_CLKCTRL_ID_Pos)));
  #endif
      while (GCLK->STATUS.bit.SYNCBUSY) {}
  
      switch (dev) {
  #if TIMER_0_EN
      case TIMER_0:
          if (TIMER_0_DEV.CTRLA.bit.ENABLE) {
              return 0;
          }
          PM->APBCMASK.reg |= PM_APBCMASK_TC3;
          /* reset timer */
          TIMER_0_DEV.CTRLA.bit.SWRST = 1;
          while (TIMER_0_DEV.CTRLA.bit.SWRST) {}
          /* choosing 16 bit mode */
          TIMER_0_DEV.CTRLA.bit.MODE = TC_CTRLA_MODE_COUNT16_Val;
  #if CLOCK_USE_PLL
          /* sourced by 1MHz with prescaler 1 results in... you know it :-) */
          TIMER_0_DEV.CTRLA.bit.PRESCALER = TC_CTRLA_PRESCALER_DIV1_Val;
  #else
          /* sourced by 8MHz with Presc 8 results in 1MHz clk */
          TIMER_0_DEV.CTRLA.bit.PRESCALER = TC_CTRLA_PRESCALER_DIV8_Val;
  #endif
          /* choose normal frequency operation */
          TIMER_0_DEV.CTRLA.bit.WAVEGEN = TC_CTRLA_WAVEGEN_NFRQ_Val;
          break;
  #endif
  #if TIMER_1_EN
      case TIMER_1:
          if (TIMER_1_DEV.CTRLA.bit.ENABLE) {
              return 0;
          }
          PM->APBCMASK.reg |= PM_APBCMASK_TC4;
          /* reset timer */
          TIMER_1_DEV.CTRLA.bit.SWRST = 1;
  
          while (TIMER_1_DEV.CTRLA.bit.SWRST) {}
  
  
          TIMER_1_DEV.CTRLA.bit.MODE = TC_CTRLA_MODE_COUNT32_Val;
  #if CLOCK_USE_PLL
          /* sourced by 1MHz and prescaler 1 to reach 1MHz */
          TIMER_1_DEV.CTRLA.bit.PRESCALER = TC_CTRLA_PRESCALER_DIV1_Val;
  #else
          /* sourced by 8MHz with Presc 8 results in 1Mhz clk */
          TIMER_1_DEV.CTRLA.bit.PRESCALER = TC_CTRLA_PRESCALER_DIV8_Val;
  #endif
          /* choose normal frequency operation */
          TIMER_1_DEV.CTRLA.bit.WAVEGEN = TC_CTRLA_WAVEGEN_NFRQ_Val;
          break;
  #endif
      case TIMER_UNDEFINED:
      default:
          return -1;
      }
  
      /* save callback */
      config[dev].cb = cb;
      config[dev].arg = arg;
  
      /* enable interrupts for given timer */
      timer_irq_enable(dev);
  
      timer_start(dev);
  
      return 0;
  }
  
  int timer_set(tim_t dev, int channel, unsigned int timeout)
  {
      return timer_set_absolute(dev, channel, timer_read(dev) + timeout);
  }
  
  int timer_set_absolute(tim_t dev, int channel, unsigned int value)
  {
      DEBUG("Setting timer %i channel %i to %i\n", dev, channel, value);
  
      /* get timer base register address */
      switch (dev) {
  #if TIMER_0_EN
      case TIMER_0:
          /* set timeout value */
          switch (channel) {
          case 0:
              TIMER_0_DEV.INTFLAG.bit.MC0 = 1;
              TIMER_0_DEV.CC[0].reg = value;
              TIMER_0_DEV.INTENSET.bit.MC0 = 1;
              break;
          case 1:
              TIMER_0_DEV.INTFLAG.bit.MC1 = 1;
              TIMER_0_DEV.CC[1].reg = value;
              TIMER_0_DEV.INTENSET.bit.MC1 = 1;
              break;
          default:
              return -1;
          }
          break;
  #endif
  #if TIMER_1_EN
      case TIMER_1:
          /* set timeout value */
          switch (channel) {
          case 0:
              TIMER_1_DEV.INTFLAG.bit.MC0 = 1;
              TIMER_1_DEV.CC[0].reg = value;
              TIMER_1_DEV.INTENSET.bit.MC0 = 1;
              break;
          case 1:
              TIMER_1_DEV.INTFLAG.bit.MC1 = 1;
              TIMER_1_DEV.CC[1].reg = value;
              TIMER_1_DEV.INTENSET.bit.MC1 = 1;
              break;
          default:
              return -1;
          }
          break;
  #endif
      case TIMER_UNDEFINED:
      default:
          return -1;
      }
  
      return 1;
  }
  
  int timer_clear(tim_t dev, int channel)
  {
      /* get timer base register address */
      switch (dev) {
  #if TIMER_0_EN
      case TIMER_0:
          switch (channel) {
          case 0:
              TIMER_0_DEV.INTFLAG.bit.MC0 = 1;
              TIMER_0_DEV.INTENCLR.bit.MC0 = 1;
              break;
          case 1:
              TIMER_0_DEV.INTFLAG.bit.MC1 = 1;
              TIMER_0_DEV.INTENCLR.bit.MC1 = 1;
              break;
          default:
              return -1;
          }
          break;
  #endif
  #if TIMER_1_EN
      case TIMER_1:
          switch (channel) {
          case 0:
              TIMER_1_DEV.INTFLAG.bit.MC0 = 1;
              TIMER_1_DEV.INTENCLR.bit.MC0 = 1;
              break;
          case 1:
              TIMER_1_DEV.INTFLAG.bit.MC1 = 1;
              TIMER_1_DEV.INTENCLR.bit.MC1 = 1;
              break;
          default:
              return -1;
          }
          break;
  #endif
      case TIMER_UNDEFINED:
      default:
          return -1;
      }
  
      return 1;
  }
  
  unsigned int timer_read(tim_t dev)
  {
      switch (dev) {
  #if TIMER_0_EN
      case TIMER_0:
          /* request syncronisation */
          TIMER_0_DEV.READREQ.reg = TC_READREQ_RREQ | TC_READREQ_ADDR(0x10);
          while (TIMER_0_DEV.STATUS.bit.SYNCBUSY) {}
          return TIMER_0_DEV.COUNT.reg;
  #endif
  #if TIMER_1_EN
      case TIMER_1:
          /* request syncronisation */
          TIMER_1_DEV.READREQ.reg = TC_READREQ_RREQ | TC_READREQ_ADDR(0x10);
          while (TIMER_1_DEV.STATUS.bit.SYNCBUSY) {}
          return TIMER_1_DEV.COUNT.reg;
  #endif
      default:
          return 0;
      }
  
  
  }
  
  void timer_stop(tim_t dev)
  {
      switch (dev) {
  #if TIMER_0_EN
          case TIMER_0:
              TIMER_0_DEV.CTRLA.bit.ENABLE = 0;
              break;
  #endif
  #if TIMER_1_EN
          case TIMER_1:
              TIMER_1_DEV.CTRLA.bit.ENABLE = 0;
              break;
  #endif
          case TIMER_UNDEFINED:
              break;
      }
  }
  
  void timer_start(tim_t dev)
  {
      switch (dev) {
  #if TIMER_0_EN
          case TIMER_0:
              TIMER_0_DEV.CTRLA.bit.ENABLE = 1;
              break;
  #endif
  #if TIMER_1_EN
          case TIMER_1:
              TIMER_1_DEV.CTRLA.bit.ENABLE = 1;
              break;
  #endif
          case TIMER_UNDEFINED:
              break;
      }
  }
  
  void timer_irq_enable(tim_t dev)
  {
      switch (dev) {
  #if TIMER_0_EN
          case TIMER_0:
              NVIC_EnableIRQ(TC3_IRQn);
              break;
  #endif
  #if TIMER_1_EN
          case TIMER_1:
              NVIC_EnableIRQ(TC4_IRQn);
              break;
  #endif
          case TIMER_UNDEFINED:
              break;
      }
  }
  
  void timer_irq_disable(tim_t dev)
  {
      switch (dev) {
  #if TIMER_0_EN
          case TIMER_0:
              NVIC_DisableIRQ(TC3_IRQn);
              break;
  #endif
  #if TIMER_1_EN
          case TIMER_1:
              NVIC_DisableIRQ(TC4_IRQn);
              break;
  #endif
          case TIMER_UNDEFINED:
              break;
      }
  }
  
  #if TIMER_0_EN
  void TIMER_0_ISR(void)
  {
      if (TIMER_0_DEV.INTFLAG.bit.MC0 && TIMER_0_DEV.INTENSET.bit.MC0) {
          if(config[TIMER_0].cb) {
              TIMER_0_DEV.INTFLAG.bit.MC0 = 1;
              TIMER_0_DEV.INTENCLR.reg = TC_INTENCLR_MC0;
              config[TIMER_0].cb(config[TIMER_0].arg, 0);
          }
      }
      else if (TIMER_0_DEV.INTFLAG.bit.MC1 && TIMER_0_DEV.INTENSET.bit.MC1) {
          if(config[TIMER_0].cb) {
              TIMER_0_DEV.INTFLAG.bit.MC1 = 1;
              TIMER_0_DEV.INTENCLR.reg = TC_INTENCLR_MC1;
              config[TIMER_0].cb(config[TIMER_0].arg, 1);
          }
      }
  
      cortexm_isr_end();
  }
  #endif /* TIMER_0_EN */
  
  
  #if TIMER_1_EN
  void TIMER_1_ISR(void)
  {
      if (TIMER_1_DEV.INTFLAG.bit.MC0 && TIMER_1_DEV.INTENSET.bit.MC0) {
          if (config[TIMER_1].cb) {
              TIMER_1_DEV.INTFLAG.bit.MC0 = 1;
              TIMER_1_DEV.INTENCLR.reg = TC_INTENCLR_MC0;
              config[TIMER_1].cb(config[TIMER_1].arg, 0);
          }
      }
      else if (TIMER_1_DEV.INTFLAG.bit.MC1 && TIMER_1_DEV.INTENSET.bit.MC1) {
          if(config[TIMER_1].cb) {
              TIMER_1_DEV.INTFLAG.bit.MC1 = 1;
              TIMER_1_DEV.INTENCLR.reg = TC_INTENCLR_MC1;
              config[TIMER_1].cb(config[TIMER_1].arg, 1);
          }
      }
  
      cortexm_isr_end();
  }
  #endif /* TIMER_1_EN */