/*******************************Necessary Calculation********************************************/
(i) calculate the busclock period
         Tbus = 1 / fbus = 1 / (48 000 000) = 20.83ns
(ii) calculate the no. of cycles need for required delay
         No. cycles = Delay / Tbus = 0.01 / (20.83x10^-9) = 480000
 (iii) calculate the Prescaler
 Prescaler = No. cycles/2^16
 = 48x10^4 / 65536 = 7.32 Rounded up value being 8
 (iv) calculate the ARR value
 ARR = No. cycles/Prescaler = 48x10^4 / 8 = 60000

/************************************************************************************************/

//********************************************************************
//*                    EEE2046F C template                           *
//*==================================================================*
//* WRITTEN BY: David Kheri                                          *
//* DATE CREATED:02/05/2018                                          *
//* MODIFIED:N/A                                                     *
//*==================================================================*
//* PROGRAMMED IN: Eclipse Luna Service Release 1 (4.4.1)            *
//* DEV. BOARD:    UCT STM32 Development Board                       *
//* TARGET:    STMicroelectronics STM32F051C6                        *
//*==================================================================*
//* DESCRIPTION:                                                     *
//*                                                                  *
//********************************************************************
// INCLUDE FILES
//====================================================================
#include "lcd_stm32f0.h"
#include "stm32f0xx.h"
//====================================================================
// SYMBOLIC CONSTANTS
//====================================================================
#define DELAY1 255
#define DELAY2 5000

#define SW0 GPIO_IDR_0
#define SW1 GPIO_IDR_1
#define SW2 GPIO_IDR_2
#define SW3 GPIO_IDR_3


//====================================================================
// GLOBAL VARIABLES
//====================================================================
unsigned int bitpattern = 0;
int minutes=0;
int seconds=0;
int hundreths=0;
int temp_display_minutes=0;
int temp_display_seconds=0;
int temp_display_hundreths=0;
int display_temp_time_flag=0;
//====================================================================
// FUNCTION DECLARATIONS
//====================================================================
void init_ports();
void init_TIM14();
void Delay();
void init_NVIC();
void check_pb();
void display();
void updateTime();
void welcome_message();
void reinit_values();
//====================================================================
// MAIN FUNCTION
//====================================================================
void main(void) {

    init_LCD();
    init_ports();
    lcd_putstring("Stop Watch");
    lcd_command(LINE_TWO);
    lcd_putstring("Press SW0");
    while((GPIOA->IDR&SW0)!=0);
    init_TIM14();
    init_NVIC();// Initialise lcd
    GPIOB->ODR=1;
    for (;;) {
        //Turn PB0 on and keep it on
        check_pb();
        /*should be check pb ideally*/
//  display();
    }
}// End of main
////====================================================================
//// FUNCTION DEFINITIONS
////====================================================================
void init_ports() {

//Enable the clock for Port A so as to enable push buttons use
    RCC->AHBENR |= RCC_AHBENR_GPIOAEN;

//setting the Push Buttons in Input Mode
    GPIOA->MODER &= ~(GPIO_MODER_MODER0 |
    GPIO_MODER_MODER1 |
    GPIO_MODER_MODER2 |
    GPIO_MODER_MODER3);

//enable pull-up resistors, GPIOA_PUPDRx = 01
    GPIOA->PUPDR |= (GPIO_PUPDR_PUPDR0_0 |
    GPIO_PUPDR_PUPDR1_0 |
    GPIO_PUPDR_PUPDR2_0 |
    GPIO_PUPDR_PUPDR3_0);

//enable clock for Port B
    RCC->AHBENR |= RCC_AHBENR_GPIOBEN;

    //setting the LEDS(0-3) in Output Mode
    GPIOB->MODER |= 0x00000055;  //LED 0-4 initialized in OutPut Mode

}
void init_TIM14()
{
        // connect the APB1 bus clock to the TIM14
        RCC->APB1ENR |= RCC_APB1ENR_TIM14EN;
        //set auto reload register (ARR) and Prescaler (PSC) for required delay
        TIM14->PSC = 8;
        TIM14->ARR = 60000;
        //enable Interupts
        TIM14->DIER |= TIM_DIER_UIE;
        //enable the Timer(start the Timer)
        TIM14->CR1 |= TIM_CR1_CEN;
}
void init_NVIC()
{
    //Enable TIM14 interrupts
    NVIC_EnableIRQ(TIM14_IRQn);
}
void TIM14_IRQHandler(void)
 {
    //update the Time values
    updateTime();
    // call display() to put time Values on the LCD
    display();
    //reset the counter;
    TIM14->SR &= ~TIM_SR_UIF;
 }
void updateTime()
{
    hundreths++;
    if(hundreths==100)
    {
        seconds++;
        hundreths=0;
    }
    if(seconds==60)
    {
        minutes++;
        seconds=0;
    }
    if(minutes==60)
    {
        minutes=0;
    }

}

void display()
{
    char time[8];
    if(display_temp_time_flag==0)
    {sprintf(time,"%02d:%02d:%02d",minutes,seconds,hundreths);}
    else
    {sprintf(time,"%02d:%02d:%02d",temp_display_minutes,temp_display_seconds,temp_display_hundreths);}
    lcd_command(CLEAR);
    lcd_putstring("Time");
    lcd_command(LINE_TWO);
    lcd_putstring(time);
}




void check_pb()
{
    if((GPIOA->IDR & SW0)==0)
    {
    TIM14->SR &= ~TIM_SR_UIF;
    TIM14->CR1 |= TIM_CR1_CEN;
    display_temp_time_flag=0;
    GPIOB->ODR=1;
    }

    if((GPIOA->IDR & SW1)==0)
    {
        temp_display_minutes=minutes;
        temp_display_seconds=seconds;
        temp_display_hundreths=hundreths;
        display_temp_time_flag=1;
        GPIOB->ODR=1<<1;
    }
    if((GPIOA->IDR & SW2)==0)
    {
        display_temp_time_flag=0;
        TIM14->CR1 &= ~TIM_CR1_CEN;
        GPIOB->ODR=1<<2;
    }

    if((GPIOA->IDR & SW3)==0)
        {
            TIM14->CR1 &= ~TIM_CR1_CEN;
            reinit_values();
            welcome_message();
            display_temp_time_flag=0;
            GPIOB->ODR=1<<3;
        }
}

void reinit_values()
{
    hundreths=0;minutes=0;seconds=0;
}

void welcome_message()
{
    lcd_command(CLEAR);
    lcd_putstring("Stop Watch");
    lcd_command(LINE_TWO);
    lcd_putstring("Press SW0");
}
//Delay function used to delay counting with 1 second
void Delay() {
    for (int i = 0; i < DELAY1; i++) {
        for (int j = 0; j < DELAY2; j++) {
            __asm__("nop");
        }
    }
  }

//********************************************************************
// END OF PROGRAM
//********************************************************************