#include <XMC4700.h>
#include "xmc_ccu4.h"
#include "xmc_gpio.h"
#include "xmc_scu.h"

// fCPU=144MHz; Prescaler set to 4096
#define CALCULATE_PERIOD(interval_in_ms) ((35155 * interval_in_ms) / 1000)  

// Globale Variable für Timer-Interrupt
volatile bool timerInterruptOccurred = false;

// Globale Variable für die Timer-Periode
uint32_t timer_interval = 1000;

// Deklaration des Interrupt-Handlers für CCU43-Slice 1
extern "C" void CCU43_1_IRQHandler(void);

extern "C" void UserIRQHandler(void);

int main(void) {
  bool button_edge = true;

  /* 
  // INITIALIZE CCU43 FOR TOGGLING OF LED
  XMC_CCU4_Init(CCU43, XMC_CCU4_SLICE_MCMS_ACTION_TRANSFER_PR_CR);   
  */
  
  // Enable the clock for selected timer
  XMC_CCU4_EnableClock(CCU43, 3);

  /* 
  // Prepare configuration
  XMC_CCU4_SLICE_COMPARE_CONFIG_t slice_config =  {
    // .tc =
    0,
    // set pre-scaler to 4096
    // .prescaler_initval = 
    12, 
    // .float_limit = 
    0,
    // .dither_limit = 
    0,
    //.passive_level = 
    0,
    // .timer_concatenation = 
    0
  };

  // Configure the timer
  XMC_CCU4_SLICE_CompareInit(CCU43_CC43, &slice_config);

  // programs the timer period register according to time interval value
  XMC_CCU4_SLICE_SetTimerPeriodMatch(CCU43_CC43, 

  CALCULATE_PERIOD(timer_interval));

  // Transfers value from shadow timer registers to actual timer registers 
  XMC_CCU4_EnableShadowTransfer(CCU43, XMC_CCU4_SHADOW_TRANSFER_SLICE_3 | XMC_CCU4_SHADOW_TRANSFER_PRESCALER_SLICE_3); 

  // Bind period match event to an NVIC node CCU43_1_IRQn
  XMC_CCU4_SLICE_SetInterruptNode(CCU43_CC43, XMC_CCU4_SLICE_IRQ_ID_PERIOD_MATCH, XMC_CCU4_SLICE_SR_ID_1); 
  
  // Enables timer(period match) event 
  */
  
  XMC_CCU4_SLICE_EnableEvent(CCU43_CC43, XMC_CCU4_SLICE_IRQ_ID_PERIOD_MATCH);

  XMC_CCU4_SLICE_ClearTimer(CCU43_CC43); XMC_CCU4_SLICE_StartTimer(CCU43_CC43);

  // NVIC-Konfiguration: Priorität setzen und Interrupt aktivieren 
  NVIC_SetPriority(CCU43_1_IRQn, NVIC_EncodePriority(NVIC_GetPriorityGrouping(), 63, 0)); 
  NVIC_EnableIRQ(CCU43_1_IRQn);

  // INITIALIZE LED1 ON PORT 5.9 FOR OUTPUT (PUSH-PULL) 
  XMC_GPIO_SetMode(P5_9, XMC_GPIO_MODE_OUTPUT_PUSH_PULL);

  // INITIALIZE BUTTON1 ON PORT 15.13 FOR INPUT 
  XMC_GPIO_SetMode(P15_13, XMC_GPIO_MODE_INPUT_TRISTATE); 
  XMC_GPIO_EnableDigitalInput(P15_13);

  // INITIALIZE BUTTON2 ON PORT 15.12 FOR INPUT
  XMC_GPIO_SetMode(P15_12, XMC_GPIO_MODE_INPUT_TRISTATE); 
  XMC_GPIO_EnableDigitalInput(P15_12);

  while(1U) { 
    // any button pushed?
    if (!XMC_GPIO_GetInput(P15_13) || !XMC_GPIO_GetInput(P15_12)) {
    
      // new edge on any button?
      if (button_edge == true) { 
      
        // which button ? 
        if (!XMC_GPIO_GetInput(P15_13)) {
        
          // Button1 pushed. Decrease cycle time of flashing LED.
          timer_interval = (timer_interval > 100) ? (timer_interval - 100) : timer_interval; 
        
        } else { 
          // Button2 pushed. Increase cycle time of flashing LED. 
          timer_interval = (timer_interval < 1500) ? (timer_interval + 100) : timer_interval; 
        } 
        
        XMC_CCU4_SLICE_StopTimer(CCU43_CC43); 
        XMC_CCU4_SLICE_SetTimerPeriodMatch(CCU43_CC43, CALCULATE_PERIOD(timer_interval)); 
        XMC_CCU4_EnableShadowTransfer(CCU43, XMC_CCU4_SHADOW_TRANSFER_SLICE_3 | XMC_CCU4_SHADOW_TRANSFER_PRESCALER_SLICE_3); 
        XMC_CCU4_SLICE_StartTimer(CCU43_CC43); 
    } 
    
    button_edge = false;
    
  } else {
    // currently no button pushed
    
    // next trigger on button is new edge
    button_edge = true; 
  }
}

// Interrupt-Service-Routine für CCU43-Slice 1 
void CCU43_1_IRQHandler(void) { 
  
  // Prüfen, ob der Perioden-Match-Interrupt ausgelöst wurde 
  if (XMC_CCU4_SLICE_GetEvent(CCU43_CC43, XMC_CCU4_SLICE_IRQ_ID_PERIOD_MATCH)) { 
    
    // Interrupt-Flag löschen 
    XMC_CCU4_SLICE_ClearEvent(CCU43_CC43, XMC_CCU4_SLICE_IRQ_ID_PERIOD_MATCH);

    // LED-Zustand umschalten
    XMC_GPIO_ToggleOutput(P5_9);
  } 
}

void UserIRQHandler(void) {
  XMC_GPIO_ToggleOutput(P5_9); 
}