etl/examples/ArmTimerCallbacks - C/main.c

#include <stdio.h>

#include "Board_LED.h"     // ::Board Support:LED
#include "Board_Buttons.h" // ::Board Support:Buttons

#include "stm32f4xx.h"     // Device header

#include "ecl_timer.h"

#define N_TIMERS 4
struct ecl_timer_config timers[N_TIMERS];

ecl_timer_id_t short_toggle;
ecl_timer_id_t long_toggle;
ecl_timer_id_t start_timers;
ecl_timer_id_t swap_timers;

/*----------------------------------------------------------------------------
 * SystemCoreClockConfigure: configure SystemCoreClock using HSI
                             (HSE is not populated on Nucleo board)
 *----------------------------------------------------------------------------*/
void SystemCoreClockConfigure(void) {

  RCC->CR |= ((uint32_t)RCC_CR_HSION);                     // Enable HSI
  while ((RCC->CR & RCC_CR_HSIRDY) == 0);                  // Wait for HSI Ready

  RCC->CFGR = RCC_CFGR_SW_HSI;                             // HSI is system clock
  while ((RCC->CFGR & RCC_CFGR_SWS) != RCC_CFGR_SWS_HSI);  // Wait for HSI used as system clock

  FLASH->ACR  = FLASH_ACR_PRFTEN;                          // Enable Prefetch Buffer
  FLASH->ACR |= FLASH_ACR_ICEN;                            // Instruction cache enable
  FLASH->ACR |= FLASH_ACR_DCEN;                            // Data cache enable
  FLASH->ACR |= FLASH_ACR_LATENCY_5WS;                     // Flash 5 wait state

  RCC->CFGR |= RCC_CFGR_HPRE_DIV1;                         // HCLK = SYSCLK
  RCC->CFGR |= RCC_CFGR_PPRE1_DIV4;                        // APB1 = HCLK/4
  RCC->CFGR |= RCC_CFGR_PPRE2_DIV2;                        // APB2 = HCLK/2

  RCC->CR &= ~RCC_CR_PLLON;                                // Disable PLL

  // PLL configuration:  VCO = HSI/M * N,  Sysclk = VCO/P
  RCC->PLLCFGR = ( 16ul                   |                // PLL_M =  16
                 (384ul <<  6)            |                // PLL_N = 384
                 (  3ul << 16)            |                // PLL_P =   8
                 (RCC_PLLCFGR_PLLSRC_HSI) |                // PLL_SRC = HSI
                 (  8ul << 24)             );              // PLL_Q =   8

  RCC->CR |= RCC_CR_PLLON;                                 // Enable PLL
  while((RCC->CR & RCC_CR_PLLRDY) == 0) __NOP();           // Wait till PLL is ready

  RCC->CFGR &= ~RCC_CFGR_SW;                               // Select PLL as system clock source
  RCC->CFGR |=  RCC_CFGR_SW_PLL;
  while ((RCC->CFGR & RCC_CFGR_SWS) != RCC_CFGR_SWS_PLL);  // Wait till PLL is system clock src
}

void StartTimers()
{
  ecl_timer_start(short_toggle, ECL_TIMER_START_DELAYED);
  ecl_timer_start(swap_timers, ECL_TIMER_START_DELAYED);
}

void SwapTimers()
{
  static int state = 0;
  
  if (!state)
  {
    ecl_timer_stop(short_toggle);
    ecl_timer_start(long_toggle, ECL_TIMER_START_DELAYED);
  }
  else
  {
    ecl_timer_start(short_toggle, ECL_TIMER_START_DELAYED);
    ecl_timer_stop(long_toggle);
  }
  
  state = !state;
  
  ecl_timer_start(swap_timers, ECL_TIMER_START_DELAYED);
}

void LedToggle()
{
  static int state = 0;
  
  if (state)
  {
    LED_On(0);
  }
  else
  {
    LED_Off(0);
  }
  
  state = !state;
}

int main()
{
  SystemCoreClockConfigure();                              // configure HSI as System Clock
  SystemCoreClockUpdate();
   
  LED_Initialize();
  Buttons_Initialize();
  
  ecl_timer_init(timers, N_TIMERS);

  // The LEDs will start flashing fast after 2 seconds.
  // After another 5 seconds they will start flashing slower.  
  short_toggle = ecl_timer_register(LedToggle,    50,  ECL_TIMER_REPEATING);
  long_toggle  = ecl_timer_register(LedToggle,   100,  ECL_TIMER_REPEATING);
  start_timers = ecl_timer_register(StartTimers, 2000, ECL_TIMER_SINGLE_SHOT);
  swap_timers  = ecl_timer_register(SwapTimers,  1500, ECL_TIMER_SINGLE_SHOT);

  SysTick_Config(SystemCoreClock / 1000); 
  
  ecl_timer_enable(ECL_TIMER_ENABLED);
  
  ecl_timer_start(start_timers, ECL_TIMER_START_DELAYED);
    
  while (1)
  {
    __NOP();
  }
}

void SysTick_Handler() 
{
  const  uint32_t TICK   = 1;   
  static uint32_t nticks = TICK;
  
  if (ecl_timer_tick(nticks))
  {
    nticks = TICK;
  }
  else
  {
    nticks += TICK;
  }
}