text: /**
    ******************************************************************************
    * @file    hal_tick.c
    * @author  MCD Application Team
    * @brief   Initialization of HAL tick
    ******************************************************************************
    * @attention
    *
    * <h2><center>&copy; COPYRIGHT 2014 STMicroelectronics</center></h2>
    *
    * 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 STMicroelectronics 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.
    *
    ******************************************************************************
    */
  #include "hal_tick.h"
  
  TIM_HandleTypeDef TimMasterHandle;
  uint32_t PreviousVal = 0;
  
  void us_ticker_irq_handler(void);
  void set_compare(uint16_t count);
  
  extern volatile uint32_t SlaveCounter;
  extern volatile uint32_t oc_int_part;
  extern volatile uint16_t oc_rem_part;
  
  void timer_irq_handler(void) {
      uint16_t cval = TIM_MST->CNT;
  
      TimMasterHandle.Instance = TIM_MST;
  
      // Clear Update interrupt flag
      if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_UPDATE) == SET) {
          __HAL_TIM_CLEAR_FLAG(&TimMasterHandle, TIM_FLAG_UPDATE);
          SlaveCounter++;
      }
  
      // Channel 1 for mbed timeout
      if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC1) == SET) {
          __HAL_TIM_CLEAR_FLAG(&TimMasterHandle, TIM_FLAG_CC1);
          if (oc_rem_part > 0) {
              set_compare(oc_rem_part); // Finish the remaining time left
              oc_rem_part = 0;
          } else {
              if (oc_int_part > 0) {
                  set_compare(0xFFFF);
                  oc_rem_part = cval; // To finish the counter loop the next time
                  oc_int_part--;
              } else {
                  us_ticker_irq_handler();
              }
          }
      }
  
      // Channel 2 for HAL tick
      if (__HAL_TIM_GET_FLAG(&TimMasterHandle, TIM_FLAG_CC2) == SET) {
          __HAL_TIM_CLEAR_FLAG(&TimMasterHandle, TIM_FLAG_CC2);
          uint32_t val = __HAL_TIM_GetCounter(&TimMasterHandle);
          if ((val - PreviousVal) >= HAL_TICK_DELAY) {
              // Increment HAL variable
              HAL_IncTick();
              // Prepare next interrupt
              __HAL_TIM_SetCompare(&TimMasterHandle, TIM_CHANNEL_2, val + HAL_TICK_DELAY);
              PreviousVal = val;
          }
      }
  }
  
  // Reconfigure the HAL tick using a standard timer instead of systick.
  HAL_StatusTypeDef HAL_InitTick(uint32_t TickPriority) {
      // Enable timer clock
      TIM_MST_RCC;
  
      // Reset timer
      TIM_MST_RESET_ON;
      TIM_MST_RESET_OFF;
  
      // Update the SystemCoreClock variable
      SystemCoreClockUpdate();
  
      // Configure time base
      TimMasterHandle.Instance = TIM_MST;
      TimMasterHandle.Init.Period        = 0xFFFFFFFF;
      TimMasterHandle.Init.Prescaler     = (uint32_t)(SystemCoreClock / 1000000) - 1; // 1 us tick
      TimMasterHandle.Init.ClockDivision = 0;
      TimMasterHandle.Init.CounterMode   = TIM_COUNTERMODE_UP;
      HAL_TIM_Base_Init(&TimMasterHandle);
  
      // Configure output compare channel 1 for mbed timeout (enabled later when used)
      HAL_TIM_OC_Start(&TimMasterHandle, TIM_CHANNEL_1);
  
      // Configure output compare channel 2 for HAL tick
      HAL_TIM_OC_Start(&TimMasterHandle, TIM_CHANNEL_2);
      PreviousVal = __HAL_TIM_GetCounter(&TimMasterHandle);
      __HAL_TIM_SetCompare(&TimMasterHandle, TIM_CHANNEL_2, PreviousVal + HAL_TICK_DELAY);
  
      // Configure interrupts
      // Update interrupt used for 32-bit counter
      // Output compare channel 1 interrupt for mbed timeout
      // Output compare channel 2 interrupt for HAL tick
      NVIC_SetVector(TIM_MST_IRQ, (uint32_t)timer_irq_handler);
      NVIC_EnableIRQ(TIM_MST_IRQ);
  
      // Enable interrupts
      __HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_UPDATE); // For 32-bit counter
      __HAL_TIM_ENABLE_IT(&TimMasterHandle, TIM_IT_CC2); // For HAL tick
  
      // Enable timer
      HAL_TIM_Base_Start(&TimMasterHandle);
  
      return HAL_OK;
  }
  
  /**
    * @}
    */
  
  /**
    * @}
    */
    
  /**
    * @}
    */    
  /************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
  