/**
  ******************************************************************************
  * @file    Examples_LL/USART/USART_Communication_TxRx_DMA/Src/main.c
  * @author  MCD Application Team
  * @brief   This example describes how to send/receive bytes over USART IP using
  *          the STM32F0xx USART LL API in DMA mode.
  *          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 STM32F0xx_LL_Examples
  * @{
  */

/** @addtogroup USART_Communication_TxRx_DMA
  * @{
  */

/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/

/* Private variables ---------------------------------------------------------*/
__IO uint8_t ubButtonPress = 0;
__IO uint8_t ubSend = 0;
/* Buffer used for transmission */
const uint8_t aTxBuffer[] = "STM32F0xx USART LL API Example : TX/RX in DMA mode\r\nConfiguration UART 115200 bps, 8 data bit/1 stop bit/No parity/No HW flow control\r\nPlease enter 'END' string ...\r\n";
uint8_t ubNbDataToTransmit = sizeof(aTxBuffer);
__IO uint8_t ubTransmissionComplete = 0;

/* Buffer used for reception */
const uint8_t aStringToReceive[] = "END";
uint8_t ubNbDataToReceive = sizeof(aStringToReceive) - 1;
uint8_t aRxBuffer[sizeof(aStringToReceive) - 1];
__IO uint8_t ubReceptionComplete = 0;

/* Private function prototypes -----------------------------------------------*/
void     SystemClock_Config(void);
void     Configure_DMA(void);
void     Configure_USART(void);
void     StartTransfers(void);
void     LED_Init(void);
void     LED_On(void);
void     LED_Blinking(uint32_t Period);
void     LED_Off(void);
void     UserButton_Init(void);
void     WaitForUserButtonPress(void);
void     WaitAndCheckEndOfTransfer(void);
uint8_t  Buffercmp8(uint8_t* pBuffer1, uint8_t* pBuffer2, uint8_t BufferLength);

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

/**
  * @brief  Main program
  * @param  None
  * @retval None
  */
int main(void)
{
  /* Configure the system clock to 48 MHz */
  SystemClock_Config();

  /* Initialize LED2 */
  LED_Init();

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

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

  /* Configure DMA channels for USART instance */
  Configure_DMA();

  /* Wait for User push-button press to start transfer */
  WaitForUserButtonPress();
  
  /* Initiate DMA transfers */
  StartTransfers();
  
  /* Wait for the end of the transfer and check received data */
  WaitAndCheckEndOfTransfer();

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

/**
  * @brief  This function configures the DMA Channels for TX and RX transfers
  * @note   This function is used to :
  *         -1- Enable DMA1 clock
  *         -2- Configure NVIC for DMA transfer complete/error interrupts 
  *         -3- Configure DMA TX channel functional parameters
  *         -4- Configure DMA RX channel functional parameters
  *         -5- Enable transfer complete/error interrupts
  * @param  None
  * @retval None
  */
void Configure_DMA(void)
{
  /* DMA1 used for USART2 Transmission and Reception
   */
  /* (1) Enable the clock of DMA1 */
  LL_AHB1_GRP1_EnableClock(LL_AHB1_GRP1_PERIPH_DMA1);

  /* (2) Configure NVIC for DMA transfer complete/error interrupts */
  NVIC_SetPriority(DMA1_Channel4_5_6_7_IRQn, 0);
  NVIC_EnableIRQ(DMA1_Channel4_5_6_7_IRQn);

  /* (3) Configure the DMA functional parameters for transmission */
  LL_DMA_ConfigTransfer(DMA1, LL_DMA_CHANNEL_4, 
                        LL_DMA_DIRECTION_MEMORY_TO_PERIPH | 
                        LL_DMA_PRIORITY_HIGH              | 
                        LL_DMA_MODE_NORMAL                | 
                        LL_DMA_PERIPH_NOINCREMENT         | 
                        LL_DMA_MEMORY_INCREMENT           | 
                        LL_DMA_PDATAALIGN_BYTE            | 
                        LL_DMA_MDATAALIGN_BYTE);
  LL_DMA_ConfigAddresses(DMA1, LL_DMA_CHANNEL_4,
                         (uint32_t)aTxBuffer,
                         LL_USART_DMA_GetRegAddr(USART2, LL_USART_DMA_REG_DATA_TRANSMIT),
                         LL_DMA_GetDataTransferDirection(DMA1, LL_DMA_CHANNEL_4));
  LL_DMA_SetDataLength(DMA1, LL_DMA_CHANNEL_4, ubNbDataToTransmit);

  /* (4) Configure the DMA functional parameters for reception */
  LL_DMA_ConfigTransfer(DMA1, LL_DMA_CHANNEL_5, 
                        LL_DMA_DIRECTION_PERIPH_TO_MEMORY | 
                        LL_DMA_PRIORITY_HIGH              | 
                        LL_DMA_MODE_NORMAL                | 
                        LL_DMA_PERIPH_NOINCREMENT         | 
                        LL_DMA_MEMORY_INCREMENT           | 
                        LL_DMA_PDATAALIGN_BYTE            | 
                        LL_DMA_MDATAALIGN_BYTE);
  LL_DMA_ConfigAddresses(DMA1, LL_DMA_CHANNEL_5,
                         LL_USART_DMA_GetRegAddr(USART2, LL_USART_DMA_REG_DATA_RECEIVE),
                         (uint32_t)aRxBuffer,
                         LL_DMA_GetDataTransferDirection(DMA1, LL_DMA_CHANNEL_5));
  LL_DMA_SetDataLength(DMA1, LL_DMA_CHANNEL_5, ubNbDataToReceive);

  /* (5) Enable DMA transfer complete/error interrupts  */
  LL_DMA_EnableIT_TC(DMA1, LL_DMA_CHANNEL_4);
  LL_DMA_EnableIT_TE(DMA1, LL_DMA_CHANNEL_4);
  LL_DMA_EnableIT_TC(DMA1, LL_DMA_CHANNEL_5);
  LL_DMA_EnableIT_TE(DMA1, LL_DMA_CHANNEL_5);
}

/**
  * @brief  This function configures USARTx Instance.
  * @note   This function is used to :
  *         -1- Enable GPIO clock and configures the USART2 pins.
  *         -2- Enable the USART2 peripheral clock and clock source.
  *         -3- Configure USART2 functional parameters.
  *         -4- Enable USART2.
  * @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 */
  LL_AHB1_GRP1_EnableClock(LL_AHB1_GRP1_PERIPH_GPIOA);

  /* Configure Tx Pin as : Alternate function, High Speed, Push pull, Pull up */
  LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_2, LL_GPIO_MODE_ALTERNATE);
  LL_GPIO_SetAFPin_0_7(GPIOA, LL_GPIO_PIN_2, LL_GPIO_AF_1);
  LL_GPIO_SetPinSpeed(GPIOA, LL_GPIO_PIN_2, LL_GPIO_SPEED_FREQ_HIGH);
  LL_GPIO_SetPinOutputType(GPIOA, LL_GPIO_PIN_2, LL_GPIO_OUTPUT_PUSHPULL);
  LL_GPIO_SetPinPull(GPIOA, LL_GPIO_PIN_2, LL_GPIO_PULL_UP);

  /* Configure Rx Pin as : Alternate function, High Speed, Push pull, Pull up */
  LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_3, LL_GPIO_MODE_ALTERNATE);
  LL_GPIO_SetAFPin_0_7(GPIOA, LL_GPIO_PIN_3, LL_GPIO_AF_1);
  LL_GPIO_SetPinSpeed(GPIOA, LL_GPIO_PIN_3, LL_GPIO_SPEED_FREQ_HIGH);
  LL_GPIO_SetPinOutputType(GPIOA, LL_GPIO_PIN_3, LL_GPIO_OUTPUT_PUSHPULL);
  LL_GPIO_SetPinPull(GPIOA, LL_GPIO_PIN_3, LL_GPIO_PULL_UP);

  /* (2) Enable USART2 peripheral clock and clock source ****************/
  LL_APB1_GRP1_EnableClock(LL_APB1_GRP1_PERIPH_USART2);

  /* Set clock source */
  LL_RCC_SetUSARTClockSource(LL_RCC_USART2_CLKSOURCE_PCLK1);

  /* (3) Configure USART2 functional parameters ********************************/
  
  /* Disable USART prior modifying configuration registers */
  /* Note: Commented as corresponding to Reset value */
  // LL_USART_Disable(USART2);

  /* TX/RX direction */
  LL_USART_SetTransferDirection(USART2, LL_USART_DIRECTION_TX_RX);

  /* 8 data bit, 1 start bit, 1 stop bit, no parity */
  LL_USART_ConfigCharacter(USART2, 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(USART2, LL_USART_HWCONTROL_NONE);

  /* Oversampling by 16 */
  /* Reset value is LL_USART_OVERSAMPLING_16 */
  // LL_USART_SetOverSampling(USART2, LL_USART_OVERSAMPLING_16);

  /* Set Baudrate to 115200 using APB frequency set to 48000000 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 48000000 Hz => equal to SystemCoreClock
  */
  LL_USART_SetBaudRate(USART2, SystemCoreClock, LL_USART_OVERSAMPLING_16, 115200); 

  /* (4) Enable USART2 **********************************************************/
  LL_USART_Enable(USART2);

  /* Polling USART initialisation */
  while((!(LL_USART_IsActiveFlag_TEACK(USART2))) || (!(LL_USART_IsActiveFlag_REACK(USART2))))
  { 
  }
}

/**
  * @brief  This function initiates TX and RX DMA transfers by enabling DMA channels
  * @param  None
  * @retval None
  */
void StartTransfers(void)
{
  /* Enable DMA RX Interrupt */
  LL_USART_EnableDMAReq_RX(USART2);

  /* Enable DMA TX Interrupt */
  LL_USART_EnableDMAReq_TX(USART2);

  /* Enable DMA Channel Rx */
  LL_DMA_EnableChannel(DMA1, LL_DMA_CHANNEL_5);

  /* Enable DMA Channel Tx */
  LL_DMA_EnableChannel(DMA1, LL_DMA_CHANNEL_4);
}

/**
  * @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);
  LL_GPIO_SetPinPull(USER_BUTTON_GPIO_PORT, USER_BUTTON_PIN, LL_GPIO_PULL_NO);

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

  /* Enable a rising trigger EXTI_Line4_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  Wait for User push-button press to start transfer.
  * @param  None 
  * @retval None
  */
  /*  */
void WaitForUserButtonPress(void)
{
  while (ubButtonPress == 0)
  {
    LL_GPIO_TogglePin(LED2_GPIO_PORT, LED2_PIN);
    LL_mDelay(LED_BLINK_FAST);
  }
  /* Ensure that LED2 is turned Off */
  LED_Off();
}

/**
  * @brief  Wait end of transfer and check if received Data are well.
  * @param  None 
  * @retval None
  */
void WaitAndCheckEndOfTransfer(void)
{
  /* 1 - Wait end of transmission */
  while (ubTransmissionComplete != 1)
  {
  }
  /* Disable DMA1 Tx Channel */
  LL_DMA_DisableChannel(DMA1, LL_DMA_CHANNEL_4);

  /* 2 - Wait end of reception */
  while (ubReceptionComplete != 1)
  {
  }
  /* Disable DMA1 Rx Channel */
  LL_DMA_DisableChannel(DMA1, LL_DMA_CHANNEL_5);

  /* 3 - Compare received string to expected one */
  if(Buffercmp8((uint8_t*)aStringToReceive, (uint8_t*)aRxBuffer, ubNbDataToReceive))
  {
    /* Processing Error */
    LED_Blinking(LED_BLINK_ERROR);    
  }
  else
  {
    /* Turn On Led if data are well received */
    LED_On();
  }
}

/**
* @brief Compares two 8-bit buffers and returns the comparison result.
* @param pBuffer1: pointer to the source buffer to be compared to.
* @param pBuffer2: pointer to the second source buffer to be compared to the first.
* @param BufferLength: buffer's length.
* @retval   0: Comparison is OK (the two Buffers are identical)
*           Value different from 0: Comparison is NOK (Buffers are different)
*/
uint8_t Buffercmp8(uint8_t* pBuffer1, uint8_t* pBuffer2, uint8_t BufferLength)
{
  while (BufferLength--)
  {
    if (*pBuffer1 != *pBuffer2)
    {
      return 1;
    }

    pBuffer1++;
    pBuffer2++;
  }

  return 0;
}

/**
  * @brief  System Clock Configuration
  *         The system Clock is configured as follow : 
  *            System Clock source            = PLL (HSI48)
  *            SYSCLK(Hz)                     = 48000000
  *            HCLK(Hz)                       = 48000000
  *            AHB Prescaler                  = 1
  *            APB1 Prescaler                 = 1
  *            HSI Frequency(Hz)              = 48000000
  *            PREDIV                         = 2
  *            PLLMUL                         = 2
  *            Flash Latency(WS)              = 1
  * @param  None
  * @retval None
  */
void SystemClock_Config(void)
{
  /* Set FLASH latency */ 
  LL_FLASH_SetLatency(LL_FLASH_LATENCY_1);

  /* Enable HSI48 and wait for activation*/
  LL_RCC_HSI48_Enable(); 
  while(LL_RCC_HSI48_IsReady() != 1) 
  {
  };
  
  /* Main PLL configuration and activation */
  LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSI48, LL_RCC_PLL_MUL_2, LL_RCC_PREDIV_DIV_2);
  
  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 prescaler */
  LL_RCC_SetAPB1Prescaler(LL_RCC_APB1_DIV_1);
  
  /* Set systick to 1ms in using frequency set to 48MHz */
  /* This frequency can be calculated through LL RCC macro */
  /* ex: __LL_RCC_CALC_PLLCLK_FREQ (HSI48_VALUE, LL_RCC_PLL_MUL_2, LL_RCC_PREDIV_DIV_2) */
  LL_Init1msTick(48000000);
  
  /* Update CMSIS variable (which can be updated also through SystemCoreClockUpdate function) */
  LL_SetSystemCoreClock(48000000);
}

/******************************************************************************/
/*   USER IRQ HANDLER TREATMENT Functions                                     */
/******************************************************************************/
/**
  * @brief  Function to manage User push-button
  * @param  None
  * @retval None
  */
void UserButton_Callback(void)
{
  /* Update User push-button variable : to be checked in waiting loop in main program */
  ubButtonPress = 1;
}

/**
  * @brief  Function called from DMA1 IRQ Handler when Tx transfer is completed 
  * @param  None
  * @retval None
  */
void DMA1_TransmitComplete_Callback(void)
{
  /* DMA Tx transfer completed */
  ubTransmissionComplete = 1;
}

/**
  * @brief  Function called from DMA1 IRQ Handler when Rx transfer is completed 
  * @param  None
  * @retval None
  */
void DMA1_ReceiveComplete_Callback(void)
{
  /* DMA Rx transfer completed */
  ubReceptionComplete = 1;
}

/**
  * @brief  Function called in case of error detected in USART IT Handler
  * @param  None
  * @retval None
  */
void USART_TransferError_Callback(void)
{
  /* Disable DMA1 Tx Channel */
  LL_DMA_DisableChannel(DMA1, LL_DMA_CHANNEL_4);

  /* Disable DMA1 Rx Channel */
  LL_DMA_DisableChannel(DMA1, LL_DMA_CHANNEL_5);

  /* Set LED2 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****/
