/**
  ******************************************************************************
  * @file    Templates/Src/main.c 
  * @author  MCD Application Team
  * @brief   Main program body
  ******************************************************************************
  * @attention
  *
  * Copyright (c) 2017 STMicroelectronics.
  * All rights reserved.
  *
  * This software is licensed under terms that can be found in the LICENSE file
  * in the root directory of this software component.
  * If no LICENSE file comes with this software, it is provided AS-IS.
  *
  ******************************************************************************
  */

/* Includes ------------------------------------------------------------------*/
#include "main.h"

/** @addtogroup STM32L4xx_HAL_Examples
  * @{
  */

/** @addtogroup Templates
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
/* Private function prototypes -----------------------------------------------*/
static void SystemClock_Config(void);
void led_on(void);
void uart_init(void);
USART_HandleTypeDef UsartHandle;
static void Error_Handler(void);
void SwithToExti(void);
uint8_t aTxBuffer[] = " ****UART_TwoBoards communication based on DMA****  ****UART_TwoBoards communication based on DMA****  ****UART_TwoBoards communication based on DMA**** ";
/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{

  /* STM32L4xx HAL library initialization:
       - Configure the Flash prefetch and Buffer caches
       - Systick timer is configured by default as source of time base, but user 
             can eventually implement his proper time base source (a general purpose 
             timer for example or other time source), keeping in mind that Time base 
             duration should be kept 1ms since PPP_TIMEOUT_VALUEs are defined and 
             handled in milliseconds basis.
       - Low Level Initialization
     */
  HAL_Init();

  /* Configure the System clock to have a frequency of 80 MHz */
  SystemClock_Config();

  /* Add your application code here
     */
  GPIO_InitTypeDef GPIO_InitStruct = {0};  
  __HAL_RCC_GPIOB_CLK_ENABLE();
  
  /* Configure the GPIO_LED pin */
  GPIO_InitStruct.Pin   = GPIO_PIN_13;
  GPIO_InitStruct.Mode  = GPIO_MODE_OUTPUT_PP;
  GPIO_InitStruct.Pull  = GPIO_NOPULL;
  GPIO_InitStruct.Speed = GPIO_SPEED_FREQ_HIGH;
  HAL_GPIO_Init(GPIOB, &GPIO_InitStruct);
  
  uart_init();
  
  if(HAL_USART_Transmit(&UsartHandle, (uint8_t*)aTxBuffer, 10,500)!= HAL_OK)
  {
    Error_Handler();
  } 
  
  SwithToExti();
    
  HAL_SuspendTick();

  HAL_PWREx_EnterSTOP2Mode(PWR_STOPENTRY_WFI); 

  HAL_ResumeTick();
  
  while (1)
  {

  }
}
void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
{
  led_on();
  HAL_NVIC_DisableIRQ(EXTI3_IRQn);
  uart_init();
  
  if(HAL_USART_Transmit(&UsartHandle, (uint8_t*)aTxBuffer, 10,500)!= HAL_OK)
  {
    Error_Handler();
  } 
}

void uart_init(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};
    /* Enable GPIO TX/RX clock */
  __HAL_RCC_GPIOA_CLK_ENABLE();


  __HAL_RCC_USART2_CLK_ENABLE();

  GPIO_InitStruct.Pin       = GPIO_PIN_3;
  GPIO_InitStruct.Mode      = GPIO_MODE_AF_PP;
  GPIO_InitStruct.Pull      = GPIO_PULLUP;
  GPIO_InitStruct.Speed     = GPIO_SPEED_FREQ_HIGH;
  GPIO_InitStruct.Alternate = GPIO_AF7_USART2;

  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
  
  GPIO_InitStruct.Pin       = GPIO_PIN_3;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);
  
  UsartHandle.Instance             = USART2;
  UsartHandle.Init.BaudRate        = 9600;
  UsartHandle.Init.WordLength      = USART_WORDLENGTH_8B;
  UsartHandle.Init.StopBits        = USART_STOPBITS_1;
  UsartHandle.Init.Parity          = USART_PARITY_NONE;
  UsartHandle.Init.Mode            = USART_MODE_TX_RX;
  UsartHandle.Init.CLKPolarity     = USART_POLARITY_LOW;
  UsartHandle.Init.CLKPhase        = USART_PHASE_1EDGE;
  UsartHandle.Init.CLKLastBit      = USART_LASTBIT_ENABLE;

  if(HAL_USART_Init(&UsartHandle) != HAL_OK)
  {
    /* Initialization Error */
    Error_Handler();
  }
}

void SwithToExti(void)
{
  GPIO_InitTypeDef GPIO_InitStruct = {0};

  /* GPIO Ports Clock Enable */
  __HAL_RCC_GPIOA_CLK_ENABLE();
  
  /*Configure GPIO pin : PA3 */
  GPIO_InitStruct.Pin = GPIO_PIN_3;
  GPIO_InitStruct.Mode = GPIO_MODE_IT_RISING;
  GPIO_InitStruct.Pull = GPIO_NOPULL;
  HAL_GPIO_Init(GPIOA, &GPIO_InitStruct);

  /* EXTI interrupt init*/
  HAL_NVIC_SetPriority(EXTI3_IRQn, 0, 0);
  HAL_NVIC_EnableIRQ(EXTI3_IRQn);
}

void led_on(void)
{
  HAL_GPIO_WritePin(GPIOB, GPIO_PIN_13, GPIO_PIN_SET);

}
/**
  * @brief  System Clock Configuration
  *         The system Clock is configured as follow : 
  *            System Clock source            = PLL (MSI)
  *            SYSCLK(Hz)                     = 80000000
  *            HCLK(Hz)                       = 80000000
  *            AHB Prescaler                  = 1
  *            APB1 Prescaler                 = 1
  *            APB2 Prescaler                 = 1
  *            MSI Frequency(Hz)              = 4000000
  *            PLL_M                          = 1
  *            PLL_N                          = 40
  *            PLL_R                          = 2
  *            PLL_P                          = 7
  *            PLL_Q                          = 4
  *            Flash Latency(WS)              = 4
  * @param  None
  * @retval None
  */
static void SystemClock_Config(void)
{
  RCC_ClkInitTypeDef RCC_ClkInitStruct;
  RCC_OscInitTypeDef RCC_OscInitStruct;

  /* MSI is enabled after System reset, activate PLL with MSI as source */
  RCC_OscInitStruct.OscillatorType = RCC_OSCILLATORTYPE_MSI;
  RCC_OscInitStruct.MSIState = RCC_MSI_ON;
  RCC_OscInitStruct.MSIClockRange = RCC_MSIRANGE_6;
  RCC_OscInitStruct.MSICalibrationValue = RCC_MSICALIBRATION_DEFAULT;
  RCC_OscInitStruct.PLL.PLLState = RCC_PLL_ON;
  RCC_OscInitStruct.PLL.PLLSource = RCC_PLLSOURCE_MSI;
  RCC_OscInitStruct.PLL.PLLM = 1;
  RCC_OscInitStruct.PLL.PLLN = 40;
  RCC_OscInitStruct.PLL.PLLR = 2;
  RCC_OscInitStruct.PLL.PLLP = 7;
  RCC_OscInitStruct.PLL.PLLQ = 4;
  if(HAL_RCC_OscConfig(&RCC_OscInitStruct) != HAL_OK)
  {
    /* Initialization Error */
    while(1);
  }
  
  /* Select PLL as system clock source and configure the HCLK, PCLK1 and PCLK2 
     clocks dividers */
  RCC_ClkInitStruct.ClockType = (RCC_CLOCKTYPE_SYSCLK | RCC_CLOCKTYPE_HCLK | RCC_CLOCKTYPE_PCLK1 | RCC_CLOCKTYPE_PCLK2);
  RCC_ClkInitStruct.SYSCLKSource = RCC_SYSCLKSOURCE_PLLCLK;
  RCC_ClkInitStruct.AHBCLKDivider = RCC_SYSCLK_DIV1;
  RCC_ClkInitStruct.APB1CLKDivider = RCC_HCLK_DIV1;  
  RCC_ClkInitStruct.APB2CLKDivider = RCC_HCLK_DIV1;  
  if(HAL_RCC_ClockConfig(&RCC_ClkInitStruct, FLASH_LATENCY_4) != HAL_OK)
  {
    /* Initialization Error */
    while(1);
  }
}

static void Error_Handler(void)
{
  while(1); 
}
#ifdef  USE_FULL_ASSERT

/**
  * @brief  Reports the name of the source file and the source line number
  *         where the assert_param error has occurred.
  * @param  file: pointer to the source file name
  * @param  line: assert_param error line source number
  * @retval None
  */
void assert_failed(uint8_t *file, uint32_t line)
{ 
  /* User can add his own implementation to report the file name and line number,
     ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */

  /* Infinite loop */
  while (1)
  {
  }
}
#endif

/**
  * @}
  */ 

/**
  * @}
  */