/**
  ******************************************************************************
  * @file    Examples_LL/USART/USART_Communication_Rx_IT/Src/main.c
  * @author  MCD Application Team
  * @version V1.0.0
  * @date    14-April-2017
  * @brief   This example describes how to send bytes over USART IP using
  *          the STM32F1xx USART LL API.
  *          Peripheral initialization done using LL unitary services functions.
  ******************************************************************************
  * @attention
  *
  * <h2><center>&copy; COPYRIGHT(c) 2016 STMicroelectronics</center></h2>
  *
  * Redistribution and use in source and binary forms, with or without modification,
  * are permitted provided that the following conditions are met:
  *   1. Redistributions of source code must retain the above copyright notice,
  *      this list of conditions and the following disclaimer.
  *   2. Redistributions in binary form must reproduce the above copyright notice,
  *      this list of conditions and the following disclaimer in the documentation
  *      and/or other materials provided with the distribution.
  *   3. Neither the name of STMicroelectronics nor the names of its contributors
  *      may be used to endorse or promote products derived from this software
  *      without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
  * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE
  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
  * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
  * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  *
  ******************************************************************************
  */

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

/** @addtogroup STM32F1xx_LL_Examples
  * @{
  */

/** @addtogroup USART_Communication_Rx_IT
  * @{
  */

/* Private typedef -----------------------------------------------------------*/

/* Private define ------------------------------------------------------------*/

/* Private macro -------------------------------------------------------------*/

/* Private variables ---------------------------------------------------------*/

/* Private function prototypes -----------------------------------------------*/
void     SystemClock_Config(void);
void     Configure_USART(void);
void     LED_Init(void);
void     LED_On(void);
void     LED_Off(void);
void     LED_Blinking(uint32_t Period);
void     UserButton_Init(void);

/* Private functions ---------------------------------------------------------*/

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /* Configure the system clock to 72 MHz */
  SystemClock_Config();

  /* Initialize LED2 */
  LED_Init();

  /* Set LED2 Off */
  LED_Off();

  /* Initialize button in EXTI mode */
  UserButton_Init();

  /* Configure USARTx (USART IP configuration and related GPIO initialization) */
  Configure_USART();

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

/**
  * @brief  This function configures USARTx Instance.
  * @note   This function is used to :
  *         -1- Enable GPIO clock, USART clock and configures the USART pins.
  *         -2- NVIC Configuration for USART interrupts.
  *         -3- Configure USART functional parameters.
  *         -4- Enable USART.
  * @note   Peripheral configuration is minimal configuration from reset values.
  *         Thus, some useless LL unitary functions calls below are provided as
  *         commented examples - setting is default configuration from reset.
  * @param  None
  * @retval None
  */
void Configure_USART(void)
{

  /* (1) Enable GPIO clock and configures the USART pins *********************/

  /* Enable the peripheral clock of GPIO Port */
  USARTx_GPIO_CLK_ENABLE();

  /* Enable USART peripheral clock *******************************************/
  USARTx_CLK_ENABLE();

  /* Configure Tx Pin as : Alternate function, High Speed, Push pull, Pull up */
  LL_GPIO_SetPinMode(USARTx_TX_GPIO_PORT, USARTx_TX_PIN, LL_GPIO_MODE_ALTERNATE);
  LL_GPIO_SetPinSpeed(USARTx_TX_GPIO_PORT, USARTx_TX_PIN, LL_GPIO_SPEED_FREQ_HIGH);
  LL_GPIO_SetPinOutputType(USARTx_TX_GPIO_PORT, USARTx_TX_PIN, LL_GPIO_OUTPUT_PUSHPULL);
  LL_GPIO_SetPinPull(USARTx_TX_GPIO_PORT, USARTx_TX_PIN, LL_GPIO_PULL_UP);

  /* Configure Rx Pin as : Input Floating function, High Speed, Pull up */
  LL_GPIO_SetPinMode(USARTx_RX_GPIO_PORT, USARTx_RX_PIN, LL_GPIO_MODE_FLOATING);
  LL_GPIO_SetPinSpeed(USARTx_RX_GPIO_PORT, USARTx_RX_PIN, LL_GPIO_SPEED_FREQ_HIGH);
  LL_GPIO_SetPinPull(USARTx_RX_GPIO_PORT, USARTx_RX_PIN, LL_GPIO_PULL_UP);

  /* (2) NVIC Configuration for USART interrupts */
  /*  - Set priority for USARTx_IRQn */
  /*  - Enable USARTx_IRQn */
  NVIC_SetPriority(USARTx_IRQn, 0);  
  NVIC_EnableIRQ(USARTx_IRQn);

  /* (3) Configure USART functional parameters ********************************/
  
  /* Disable USART prior modifying configuration registers */
  /* Note: Commented as corresponding to Reset value */
  // LL_USART_Disable(USARTx_INSTANCE);

  /* TX/RX direction */
  LL_USART_SetTransferDirection(USARTx_INSTANCE, LL_USART_DIRECTION_TX_RX);

  /* 8 data bit, 1 start bit, 1 stop bit, no parity */
  LL_USART_ConfigCharacter(USARTx_INSTANCE, LL_USART_DATAWIDTH_8B, LL_USART_PARITY_NONE, LL_USART_STOPBITS_1);

  /* No Hardware Flow control */
  /* Reset value is LL_USART_HWCONTROL_NONE */
  // LL_USART_SetHWFlowCtrl(USARTx_INSTANCE, LL_USART_HWCONTROL_NONE);

  /* Set Baudrate to 115200 using APB frequency set to 72000000/APB_Div Hz */
  /* Frequency available for USART peripheral can also be calculated through LL RCC macro */
  /* Ex :
      Periphclk = LL_RCC_GetUSARTClockFreq(Instance); or LL_RCC_GetUARTClockFreq(Instance); depending on USART/UART instance
  
      In this example, Peripheral Clock is expected to be equal to 72000000/APB_Div Hz => equal to SystemCoreClock/APB_Div
  */
  LL_USART_SetBaudRate(USARTx_INSTANCE, SystemCoreClock/APB_Div, 115200); 

  /* (4) Enable USART *********************************************************/
  LL_USART_Enable(USARTx_INSTANCE);

  /* Enable RXNE and Error interrupts */
  LL_USART_EnableIT_RXNE(USARTx_INSTANCE);
  LL_USART_EnableIT_ERROR(USARTx_INSTANCE);
}

/**
  * @brief  Initialize LED2.
  * @param  None
  * @retval None
  */
void LED_Init(void)
{
  /* Enable the LED2 Clock */
  LED2_GPIO_CLK_ENABLE();

  /* Configure IO in output push-pull mode to drive external LED2 */
  LL_GPIO_SetPinMode(LED2_GPIO_PORT, LED2_PIN, LL_GPIO_MODE_OUTPUT);
  /* Reset value is LL_GPIO_OUTPUT_PUSHPULL */
  //LL_GPIO_SetPinOutputType(LED2_GPIO_PORT, LED2_PIN, LL_GPIO_OUTPUT_PUSHPULL);
  /* Reset value is LL_GPIO_SPEED_FREQ_LOW */
  //LL_GPIO_SetPinSpeed(LED2_GPIO_PORT, LED2_PIN, LL_GPIO_SPEED_FREQ_LOW);
  /* Reset value is LL_GPIO_PULL_NO */
  //LL_GPIO_SetPinPull(LED2_GPIO_PORT, LED2_PIN, LL_GPIO_PULL_NO);
}

/**
  * @brief  Turn-on LED2.
  * @param  None
  * @retval None
  */
void LED_On(void)
{
  /* Turn LED2 on */
  LL_GPIO_SetOutputPin(LED2_GPIO_PORT, LED2_PIN);
}

/**
  * @brief  Turn-off LED2.
  * @param  None
  * @retval None
  */
void LED_Off(void)
{
  /* Turn LED2 off */
  LL_GPIO_ResetOutputPin(LED2_GPIO_PORT, LED2_PIN);
}

/**
  * @brief  Set LED2 to Blinking mode for an infinite loop (toggle period based on value provided as input parameter).
  * @param  Period : Period of time (in ms) between each toggling of LED
  *   This parameter can be user defined values. Pre-defined values used in that example are :
  *     @arg LED_BLINK_FAST : Fast Blinking
  *     @arg LED_BLINK_SLOW : Slow Blinking
  *     @arg LED_BLINK_ERROR : Error specific Blinking
  * @retval None
  */
void LED_Blinking(uint32_t Period)
{
  /* Toggle LED2 in an infinite loop */
  while (1)
  {
    LL_GPIO_TogglePin(LED2_GPIO_PORT, LED2_PIN);  
    LL_mDelay(Period);
  }
}

/**
  * @brief  Configures User push-button in GPIO or EXTI Line Mode.
  * @param  None 
  * @retval None
  */
void UserButton_Init(void)
{
  /* Enable the BUTTON Clock */
  USER_BUTTON_GPIO_CLK_ENABLE();
  
  /* Configure GPIO for BUTTON */
  LL_GPIO_SetPinMode(USER_BUTTON_GPIO_PORT, USER_BUTTON_PIN, LL_GPIO_MODE_INPUT);

  /* Connect External Line to the GPIO*/
  USER_BUTTON_SYSCFG_SET_EXTI();

  /* Enable a rising trigger External lines 10 to 15 Interrupt */
  USER_BUTTON_EXTI_LINE_ENABLE();
  USER_BUTTON_EXTI_FALLING_TRIG_ENABLE();

  /* Configure NVIC for USER_BUTTON_EXTI_IRQn */
  NVIC_SetPriority(USER_BUTTON_EXTI_IRQn, 3);  
  NVIC_EnableIRQ(USER_BUTTON_EXTI_IRQn); 
}

/**
  * @brief  System Clock Configuration
  *         The system Clock is configured as follow :
  *            System Clock source            = PLL (HSE)
  *            SYSCLK(Hz)                     = 72000000
  *            HCLK(Hz)                       = 72000000
  *            AHB Prescaler                  = 1
  *            APB1 Prescaler                 = 2
  *            APB2 Prescaler                 = 1
  *            HSE Frequency(Hz)              = 8000000
  *            PLLMUL                         = 9
  *            Flash Latency(WS)              = 2
  * @param  None
  * @retval None
  */
void SystemClock_Config(void)
{
  /* Set FLASH latency */
  LL_FLASH_SetLatency(LL_FLASH_LATENCY_2);

  /* Enable HSE oscillator */
  LL_RCC_HSE_EnableBypass();
  LL_RCC_HSE_Enable();
  while(LL_RCC_HSE_IsReady() != 1)
  {
  };

  /* Main PLL configuration and activation */
  LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSE_DIV_1, LL_RCC_PLL_MUL_9);

  LL_RCC_PLL_Enable();
  while(LL_RCC_PLL_IsReady() != 1)
  {
  };

  /* Sysclk activation on the main PLL */
  LL_RCC_SetAHBPrescaler(LL_RCC_SYSCLK_DIV_1);
  LL_RCC_SetSysClkSource(LL_RCC_SYS_CLKSOURCE_PLL);
  while(LL_RCC_GetSysClkSource() != LL_RCC_SYS_CLKSOURCE_STATUS_PLL)
  {
  };

  /* Set APB1 & APB2 prescaler*/
  LL_RCC_SetAPB1Prescaler(LL_RCC_APB1_DIV_2);
  LL_RCC_SetAPB2Prescaler(LL_RCC_APB2_DIV_1);

  /* Set systick to 1ms in using frequency set to 72MHz */
  LL_Init1msTick(72000000);

  /* Update CMSIS variable (which can be updated also through SystemCoreClockUpdate function) */
  LL_SetSystemCoreClock(72000000);
}

/******************************************************************************/
/*   IRQ HANDLER TREATMENT Functions                                          */
/******************************************************************************/
/**
  * @brief  Function to manage Button push
  * @param  None
  * @retval None
  */
void UserButton_Callback(void)
{
  /* Turn LED2 Off on User button press (allow to restart sequence) */
  LED_Off();
}

/**
  * @brief  Function called from USART IRQ Handler when RXNE flag is set
  *         Function is in charge of reading character received on USART RX line.
  * @param  None
  * @retval None
  */
void USART_CharReception_Callback(void)
{
__IO uint32_t received_char;

  /* Read Received character. RXNE flag is cleared by reading of DR register */
  received_char = LL_USART_ReceiveData8(USARTx_INSTANCE);

  /* Check if received value is corresponding to specific one : S or s */
  if ((received_char == 'S') || (received_char == 's'))
  {
    /* Turn LED2 On : Expected character has been received */
    LED_On();
  }

  /* Echo received character on TX */
  LL_USART_TransmitData8(USARTx_INSTANCE, received_char);
}

/**
  * @brief  Function called in case of error detected in USART IT Handler
  * @param  None
  * @retval None
  */
void Error_Callback(void)
{
  __IO uint32_t sr_reg;

  /* Disable USARTx_IRQn */
  NVIC_DisableIRQ(USARTx_IRQn);
  
  /* Error handling example :
    - Read USART SR register to identify flag that leads to IT raising
    - Perform corresponding error handling treatment according to flag
  */
  sr_reg = LL_USART_ReadReg(USARTx_INSTANCE, SR);
  if (sr_reg & LL_USART_SR_NE)
  {
    /* case Noise Error flag is raised : ... */
    LED_Blinking(LED_BLINK_FAST);
  }
  else
  {
    /* Unexpected IT source : Set LED to Blinking mode to indicate error occurs */
    LED_Blinking(LED_BLINK_ERROR);
  }
}

#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", file, line) */

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

/**
  * @}
  */

/**
  * @}
  */

/************************ (C) COPYRIGHT STMicroelectronics *****END OF FILE****/
