#include "stm32f4xx.h"
#include "stm32f4_discovery.h"
int counter;

int main(void)
{

    RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM4, ENABLE);
    RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);

    GPIO_InitTypeDef  GPIO_InitStructure;
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource12, GPIO_AF_TIM4);
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource13, GPIO_AF_TIM4);
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource14, GPIO_AF_TIM4);
    GPIO_PinAFConfig(GPIOD, GPIO_PinSource15, GPIO_AF_TIM4);

    GPIO_InitStructure.GPIO_Pin = GPIO_Pin_12 | GPIO_Pin_13| GPIO_Pin_14| GPIO_Pin_15 ;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF;
    GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
    GPIO_InitStructure.GPIO_PuPd = GPIO_PuPd_NOPULL;
    GPIO_Init(GPIOD, &GPIO_InitStructure);

    TIM_TimeBaseInitTypeDef TIM_TimeBaseStructure;
    TIM_TimeBaseStructure.TIM_Period = 999;
    TIM_TimeBaseStructure.TIM_Prescaler = 83;
    TIM_TimeBaseStructure.TIM_ClockDivision = TIM_CKD_DIV1;
    TIM_TimeBaseStructure.TIM_CounterMode =  TIM_CounterMode_Up;
    TIM_TimeBaseInit(TIM4, &TIM_TimeBaseStructure);

    TIM_OCInitTypeDef TIM_OCInitStructure;
    TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
    TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
    TIM_OCInitStructure.TIM_Pulse = 0;
    TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;

    TIM_OC1Init(TIM4, &TIM_OCInitStructure);
    TIM_OC1PreloadConfig(TIM4, TIM_OCPreload_Enable);

    TIM_OC2Init(TIM4, &TIM_OCInitStructure);
    TIM_OC2PreloadConfig(TIM4, TIM_OCPreload_Enable);

    TIM_OC3Init(TIM4, &TIM_OCInitStructure);
    TIM_OC3PreloadConfig(TIM4, TIM_OCPreload_Enable);

    TIM_OC4Init(TIM4, &TIM_OCInitStructure);
    TIM_OC4PreloadConfig(TIM4, TIM_OCPreload_Enable);

    TIM_Cmd(TIM4, ENABLE);


    int a=0;
    int b=250;
    int c=500;
    int d=750;
    for(;;)
    {

        if(TIM_GetFlagStatus(TIM4, TIM_FLAG_Update)) {

            TIM4 -> CCR1 = a;
            a++;
            if(a > 999) a = 0;
            TIM4 -> CCR2 = b;
            b++;
            if(b > 999) b = 0;
            TIM4 -> CCR3 = c;
            c++;
            if(c > 999) c = 0;
            TIM4 -> CCR4 = d;
            d++;
            if(d > 999) d = 0;


            TIM_ClearFlag(TIM4, TIM_FLAG_Update);
        }


    }
}