#include "stm32f4xx.h"
#include "stm32f4xx_rcc.c"
#include "stm32f4xx_adc.c"
#include "stm32f4xx_dac.c"
#include "stm32f4xx_gpio.c"
#include "stm32f4xx_tim.c"
#include "dd.h"
#include "math.h"

short int X1[1024], X2[1024], k = 0;
int w[1024];

// ADC init function
void ADCinit_T5_CC1_IRQ (void)      {
ADC_InitTypeDef         ADC_InitStructure;
GPIO_InitTypeDef        GPIO_InitStructure;
ADC_CommonInitTypeDef   ADC_CommonInitStructure;
  RCC_APB2PeriphClockCmd(RCC_APB2Periph_ADC1  | RCC_APB2Periph_ADC2,  ENABLE);
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA | RCC_AHB1Periph_GPIOB, ENABLE);
  
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_1 | GPIO_Pin_2;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AN;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOA, &GPIO_InitStructure); 
  
  ADC_CommonInitStructure.ADC_DMAAccessMode    = ADC_DMAAccessMode_Disabled;
  ADC_CommonInitStructure.ADC_Mode             = ADC_DualMode_RegSimult;
  ADC_CommonInitStructure.ADC_Prescaler        = ADC_Prescaler_Div2;
  ADC_CommonInit(&ADC_CommonInitStructure);
    
  ADC_InitStructure.ADC_Resolution             = ADC_Resolution_12b;
  ADC_InitStructure.ADC_ScanConvMode           = DISABLE;
  ADC_InitStructure.ADC_ContinuousConvMode     = DISABLE;
  ADC_InitStructure.ADC_ExternalTrigConvEdge   = ADC_ExternalTrigConvEdge_Rising;
  ADC_InitStructure.ADC_ExternalTrigConv       = ADC_ExternalTrigConv_T5_CC1;
  ADC_InitStructure.ADC_DataAlign              = ADC_DataAlign_Right;
  ADC_InitStructure.ADC_NbrOfConversion        = 1;
  ADC_Init(ADC1, &ADC_InitStructure);
  ADC_RegularChannelConfig(ADC1, ADC_Channel_1, 1, ADC_SampleTime_3Cycles);

  ADC_Init(ADC2, &ADC_InitStructure);
  ADC_RegularChannelConfig(ADC2, ADC_Channel_2, 1, ADC_SampleTime_3Cycles);

  ADC_Cmd(ADC1, ENABLE);
  ADC_Cmd(ADC2, ENABLE);

  NVIC_EnableIRQ(ADC_IRQn);                // Enable IRQ for ADC in NVIC 
  ADC_ITConfig(ADC1, ADC_IT_EOC, ENABLE);  // Enable IRQ generation in ADC 
}

// DAC init function
void DACinit (void)     {
DAC_InitTypeDef         DAC_InitStructure;
GPIO_InitTypeDef        GPIO_InitStructure;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOA, ENABLE);
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_4 | GPIO_Pin_5;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AN;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;  
  GPIO_Init(GPIOA, &GPIO_InitStructure);  
  
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_DAC, ENABLE);
  DAC_InitStructure.DAC_OutputBuffer                 = DAC_OutputBuffer_Enable;
  DAC_InitStructure.DAC_Trigger                      = DAC_Trigger_None;
  DAC_InitStructure.DAC_WaveGeneration               = DAC_WaveGeneration_None;
  DAC_Init(DAC_Channel_1, &DAC_InitStructure); 
  DAC_Init(DAC_Channel_2, &DAC_InitStructure);
  
  DAC_Cmd(DAC_Channel_1, ENABLE);   
  DAC_Cmd(DAC_Channel_2, ENABLE);
}

// Timer 5 init function - time base
void TIM5init_TimeBase_CC1 (int interval)  {
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
TIM_OCInitTypeDef       TIM_OCInitStructure;
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_TIM5,  ENABLE);
  TIM_TimeBaseInitStructure.TIM_ClockDivision = TIM_CKD_DIV1;
  TIM_TimeBaseInitStructure.TIM_CounterMode = TIM_CounterMode_Up;
  TIM_TimeBaseInitStructure.TIM_Period = interval; 
  TIM_TimeBaseInitStructure.TIM_Prescaler = 0;
  TIM_TimeBaseInitStructure.TIM_RepetitionCounter = 0;
  TIM_TimeBaseInit(TIM5, &TIM_TimeBaseInitStructure);

  TIM_OCInitStructure.TIM_OCMode = TIM_OCMode_PWM1;
  TIM_OCInitStructure.TIM_OutputState = TIM_OutputState_Enable;
  TIM_OCInitStructure.TIM_OutputNState = TIM_OutputState_Disable;
  TIM_OCInitStructure.TIM_Pulse = 1;
  TIM_OCInitStructure.TIM_OCPolarity = TIM_OCPolarity_High;
  TIM_OCInitStructure.TIM_OCNPolarity = TIM_OCNPolarity_Low;
  TIM_OCInitStructure.TIM_OCIdleState = TIM_OCIdleState_Reset;
  TIM_OCInitStructure.TIM_OCNIdleState =  TIM_OCIdleState_Set;
  TIM_OC1Init(TIM5, &TIM_OCInitStructure);

  TIM_Cmd(TIM5, ENABLE);
}   

// initialize port E, Gpio_Pin_8 to GPIO_Pin_15 as outputs
void GPIOEinit (void)   {
GPIO_InitTypeDef  GPIO_InitStructure;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_8  | GPIO_Pin_9  | GPIO_Pin_10 | GPIO_Pin_11;
  GPIO_InitStructure.GPIO_Pin  |= GPIO_Pin_12 | GPIO_Pin_13 | GPIO_Pin_14 | GPIO_Pin_15;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_OUT;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;
  GPIO_Init(GPIOE, &GPIO_InitStructure); 
}

#define pi 3.14159
int main ()  {                  

  float w0 = 2.0 * 100.0 / 10000.0;         
  w[0] = (int)(w0 * 65536);                 // central weight: 2 x fc / fs
  for (short m = 1; m < 64; m++)        
    w[m] = (int)((w0 * 65536 * sin(pi * m * w0)) / (pi * m * w0));       // other weights
  for (short m = 1; m < 64; m++)        
    w[m] = (int)((float)w[m] * cos(pi / 2 * m / 63.0));                     // windowing
  
  GPIOEinit ();
  ADCinit_T5_CC1_IRQ();
  DACinit();
  TIM5init_TimeBase_CC1(8400);           // 8400 == 100us == 10kHz

  while (1) {                            // endless loop
  };
}

// IRQ function for ADC
void ADC_IRQHandler(void)      // 9us 
{
  GPIOE->BSRRL = BIT_8;
  X1[k] = ADC1->DR;
  X2[k] = ADC2->DR;
  int conv = X1[(k - 100) & 1023] * w[0];
  for (int m = 1; m<64; m++)
    conv += w[m] *(X1[(k - 100 + m) & 1023] + X1[(k - 100 - m) & 1023]);
  DAC->DHR12R1 = X1[(k - 100) & 1023];
  DAC->DHR12R2 = conv >> 16;
  k++; k &= 1023;
  GPIOE->BSRRH = BIT_8;
}