#include "stm32f4xx.h"
#include "stm32f4xx_rcc.c"
#include "stm32f4xx_adc.c"
#include "stm32f4xx_gpio.c"
#include "stm32f4xx_usart.c"
#include "stm32f4xx_tim.c"
#include "dd.h"

char Results[65536];
int ResultsPointer = 0;        

// initialize port E (switches), Gpio_Pin_3 to GPIO_Pin_6 as inputs
void SWITCHinit (void)  {
GPIO_InitTypeDef        GPIO_InitStructure;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOE, ENABLE);
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_3 | GPIO_Pin_4 | 
                                  GPIO_Pin_5 | GPIO_Pin_6;
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_IN;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP; 
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_100MHz;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_DOWN;
  GPIO_Init(GPIOE, &GPIO_InitStructure); 
}

// initialize port D (LEDS), Gpio_Pin_12 to GPIO_Pin_15 as outputs
void LEDinit (void)     {
GPIO_InitTypeDef        GPIO_InitStructure;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
  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(GPIOD, &GPIO_InitStructure); 
}

//USART3 initialization, GPIOD 8:9, TX&RX, IRQ on RX&TX 
void USART3_init(int BaudRate)   {
GPIO_InitTypeDef        GPIO_InitStructure;
USART_InitTypeDef       USART_InitStructure;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_GPIOD, ENABLE);
  GPIO_InitStructure.GPIO_Pin   = GPIO_Pin_8 | GPIO_Pin_9; 
  GPIO_InitStructure.GPIO_Mode  = GPIO_Mode_AF;
  GPIO_InitStructure.GPIO_PuPd  = GPIO_PuPd_NOPULL;
  GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
  GPIO_InitStructure.GPIO_OType = GPIO_OType_PP;
  GPIO_Init(GPIOD, &GPIO_InitStructure); 
  GPIO_PinAFConfig(GPIOD, GPIO_PinSource8, GPIO_AF_USART3);
  GPIO_PinAFConfig(GPIOD, GPIO_PinSource9, GPIO_AF_USART3);
  
  RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE);
  USART_DeInit(USART3);
  USART_InitStructure.USART_BaudRate            = BaudRate;  
  USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
  USART_InitStructure.USART_Mode                = USART_Mode_Rx | USART_Mode_Tx;
  USART_InitStructure.USART_Parity              = USART_Parity_No;
  USART_InitStructure.USART_StopBits            = USART_StopBits_1;
  USART_InitStructure.USART_WordLength          = USART_WordLength_8b;
  USART_Init(USART3, &USART_InitStructure);
  
  USART_ITConfig(USART3, USART_IT_RXNE, ENABLE); // enable IRQ on RX
  
  USART_Cmd(USART3, ENABLE);
  NVIC_EnableIRQ(USART3_IRQn);   // Enable IRQ for USART3 in NVIC
}

// 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 
}

// 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 = 840;  // .1ms
  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);
}      

// NVIC - interrupt setup function for ADC
//void NVICinit_ADC_EOC(void)     {
//  NVIC_EnableIRQ(ADC_IRQn);                // Enable IRQ for ADC in NVIC 
//  ADC_ITConfig(ADC1, ADC_IT_EOC, ENABLE);  // Enable IRQ generation in ADC 
//}

void main(void) {
  LEDinit();
  USART3_init(921600);
  ADCinit_T5_CC1_IRQ();
  TIM5init_TimeBase_CC1(840);           // 840 == 100us
  
  while (1) {                           // endless loop
  };
}

// USART IRQ function
// caution: placing breakpoints in IRQ corrupts the execution!  
// this happens due to the reading of the DR by the IAR and changes IRQ flags!
// I wasted sevaral hours to find this out. Do not step into the same trap.
void USART3_IRQHandler(void)     {  
  // TX IRQ part
  if (USART3->SR & USART_SR_TXE) { // If TXE flag in SR is on then
    if (ResultsPointer < 65536)   // if not end of string
      USART3->DR = Results[ResultsPointer++]; // send next byte & pointer++
    else {                      // else
      USART_ITConfig(USART3, USART_IT_TXE, DISABLE);
      LED_RD_OFF;               // red OFF
    };
  };
  // RX IRQ part
  if (USART3->SR & USART_SR_RXNE) {  // if RXNE flag in SR is on then
    int RXch = USART3->DR;       // save received character & clear flag
    if (RXch == 'a') {
      LED_BL_ON;                // blue ON 
      ResultsPointer = 0;       // init pointer to results
      TIM_Cmd(TIM5, ENABLE);
    };
    if (RXch == 'b') {
      USART_ITConfig(USART3, USART_IT_TXE, ENABLE);
      ResultsPointer = 0;
      LED_RD_ON;                // red ON
      USART3->DR = Results[ResultsPointer++];   // Send first character
    };
  };
}

// ADC IRQ function
void ADC_IRQHandler(void)       // PASS takes approx 300ns of CPU time!
{
  int Ra = ADC1->DR;
  int Rb = ADC2->DR;
  if (ResultsPointer < 65535)    {
    Results[ResultsPointer++] = (Rb & 0x0f00) >> 8;
    Results[ResultsPointer++] = (Rb & 0x00ff);
  }
  else  {
    LED_BL_OFF;                 // blue OFF
    TIM_Cmd(TIM5, DISABLE);
  };
}