#include "stm32f4xx.h"
#include "stm32f4xx_rcc.c"
#include "stm32f4xx_gpio.c"
#include "stm32f4xx_usart.c"
#include "stm32f4xx_dma.c"
#include "LCD2x16.c"
#include "dd.h"

char OutString[4] = {'0', '0', 0x0a, 0x0d};

//USART3 initialization, GPIOD 8:9, TX&RX, IRQ on RX   
void USART3_init(int BaudRate)   {
USART_InitTypeDef       USART_InitStructure;  
GPIO_InitTypeDef        GPIO_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_Cmd(USART3, ENABLE);  
}

//DMA1 initialization, TX requests next character to send
void DMA1fromUSART3_init(void) {
DMA_InitTypeDef         DMA_InitStructure;
  RCC_AHB1PeriphClockCmd(RCC_AHB1Periph_DMA1, ENABLE);
  DMA_DeInit(DMA1_Stream3);                                       /* Reset DMA Stream registers (for debug purpose) */
  /* Configure DMA Stream */
  DMA_InitStructure.DMA_Channel                 = DMA_Channel_4;  
  DMA_InitStructure.DMA_PeripheralBaseAddr      = (uint32_t)(&USART3->DR);
  DMA_InitStructure.DMA_Memory0BaseAddr         = (uint32_t)(OutString);
  DMA_InitStructure.DMA_DIR                     = DMA_DIR_MemoryToPeripheral;
  DMA_InitStructure.DMA_BufferSize              = (uint32_t)4;
  DMA_InitStructure.DMA_PeripheralInc           = DMA_PeripheralInc_Disable;
  DMA_InitStructure.DMA_MemoryInc               = DMA_MemoryInc_Enable;
  DMA_InitStructure.DMA_PeripheralDataSize      = DMA_PeripheralDataSize_Byte;
  DMA_InitStructure.DMA_MemoryDataSize          = DMA_MemoryDataSize_Byte;
  DMA_InitStructure.DMA_Mode                    = DMA_Mode_Normal;
  DMA_InitStructure.DMA_Priority                = DMA_Priority_High;
  DMA_InitStructure.DMA_FIFOMode                = DMA_FIFOMode_Disable;         
  DMA_InitStructure.DMA_FIFOThreshold           = DMA_FIFOThreshold_Full;
  DMA_InitStructure.DMA_MemoryBurst             = DMA_MemoryBurst_Single;
  DMA_InitStructure.DMA_PeripheralBurst         = DMA_PeripheralBurst_Single;
  DMA_Init(DMA1_Stream3, &DMA_InitStructure);
}

void main(void) {              
unsigned Seconds = 0;
  
  USART3_init(921600);
  DMA1fromUSART3_init();
  LCD_init();                  

  while (1) {
      if (++Seconds > 59) Seconds = 0;
      unsigned x = Seconds;
      OutString[0] = x / 10   + '0';    x %= 10;
      OutString[1] = x        + '0';
      OutString[2] = '\n';      
      OutString[3] = '\r';
      //USART_ClearFlag(USART3, USART_FLAG_TC);           
      USART_DMACmd(USART3, USART_DMAReq_Tx, ENABLE);    
      DMA_ClearFlag(DMA1_Stream3, DMA_FLAG_TCIF3 | DMA_FLAG_HTIF3);            
      DMA_Cmd(DMA1_Stream3, ENABLE);            // note: USART3->SR.TXE requests DMA 

      LCD_uInt16(Seconds, 0x05, 1);             // show Seconds on LCD
      for (int i = 0; i<30000000; i++) {};      // waste about 1 s
  };
}