#include "stm32f4xx.h"
#include "stm32f4xx_rcc.c"
#include "stm32f4xx_dac.c"
#include "stm32f4xx_gpio.c"
#include "stm32f4xx_tim.c"
#include "dd.h"
#include "LCD2x16.c"
#include "math.h"

int Table[4096], ptrTable, Am = 255, k = 655;

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 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); 
}

// 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_ReloadIRQ (int interval)  {
TIM_TimeBaseInitTypeDef TIM_TimeBaseInitStructure;
  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);

  NVIC_EnableIRQ(TIM5_IRQn);                 // Enable IRQ for TIM5 in NVIC 
  TIM_ITConfig(TIM5, TIM_IT_Update, ENABLE); // Enable IRQ on update for Timer5

  TIM_Cmd(TIM5, ENABLE);
}   

int main ()  {                  
int sw, Fp, j;
  for (ptrTable = 0; ptrTable <= 4095; ptrTable++)
    Table[ptrTable] = (int)(1850.0 * sin((float)ptrTable / 2048.0 * 3.14159265));
  
  SWITCHinit ();
  GPIOEinit ();
  LCD_init (); LCD_string("Frq=", 0x01); LCD_string("Hz", 0x0d); 
  LCD_string("Amp=", 0x41);
  DACinit ();   
  TIM5init_TimeBase_ReloadIRQ(840);           // 840 == 10us

  while (1) {                                 // endless loop
    sw = GPIOE->IDR;
    if ((sw & S370) && (k  < 32768)) k++;
    if ((sw & S371) && (k  >     2)) k--;
    if ((sw & S372) && (Am <   255)) Am++;
    if ((sw & S373) && (Am >     1)) Am--;
    Fp = (int)(1.0e5 * (float)k / 65536.9);
    LCD_uInt16(Fp, 0x08, 1); LCD_uInt16(Am, 0x48, 1);
    for (j = 0; j<200000; j++){};      // waste some time
  };
}

// IRQ function for Timer5
void TIM5_IRQHandler(void)       {
  GPIOE->BSRRL = BIT_8;
  TIM_ClearITPendingBit(TIM5, TIM_IT_Update); // clear interrupt flag
  ptrTable = (ptrTable + k) & 0xffff;
  DAC->DHR12R1 = (Am * Table[  ptrTable >> 4                ]) / 256 + 2048;
  DAC->DHR12R2 = (Am * Table[((ptrTable >> 4) + 1024) & 4095]) / 256 + 2048;
  GPIOE->BSRRH = BIT_8;
}