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/**
******************************************************************************
* @file Examples_LL/USART/USART_Communication_Rx_IT_Continuous/Src/main.c
* @author MCD Application Team
* @brief This example describes how to send bytes over USART IP using
* the STM32F4xx USART LL API.
* Peripheral initialization done using LL unitary services functions.
******************************************************************************
* @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 STM32F4xx_LL_Examples
* @{
*/
/** @addtogroup USART_Communication_Rx_IT_Continuous
* @{
*/
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#define RX_BUFFER_SIZE 12
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
__IO uint8_t ubButtonPress = 0;
/**
* @brief Text strings printed on PC Com port for user information
*/
uint8_t aTextInfoStart[] = "\r\nUSART Example : Enter characters to fill reception buffers.\r\n";
uint8_t aTextInfoSwap1[] = "\r\n- Current RX buffer is full : ";
uint8_t aTextInfoSwap2[] = "\r\n- Reception will go on in alternate buffer\r\n";
/**
* @brief RX buffers for storing received data
*/
uint8_t aRXBufferA[RX_BUFFER_SIZE];
uint8_t aRXBufferB[RX_BUFFER_SIZE];
__IO uint32_t uwNbReceivedChars;
__IO uint32_t uwBufferReadyIndication;
uint8_t *pBufferReadyForUser;
uint8_t *pBufferReadyForReception;
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
void Configure_USART(void);
void StartReception(void);
void HandleContinuousReception(void);
void LED_Init(void);
void LED_Off(void);
void LED_Blinking(uint32_t Period);
void UserButton_Init(void);
void WaitForUserButtonPress(void);
void PrintInfo(uint8_t *String, uint32_t Size);
void UserDataTreatment(uint8_t *DataBuffer, uint32_t Size);
/* Private functions ---------------------------------------------------------*/
/**
* @brief Main program
* @param None
* @retval None
*/
int main(void)
{
/* Configure the system clock to 100 MHz */
SystemClock_Config();
/* Initialize LED2 */
LED_Init();
/* Set LED2 Off */
LED_Off();
/* Initialize User push-button in EXTI mode */
UserButton_Init();
/* Configure USARTx (USART IP configuration and related GPIO initialization) */
Configure_USART();
/* Wait for User push-button press to start transfer */
WaitForUserButtonPress();
/* Initiate Continuous reception */
StartReception();
/* Infinite loop */
while (1)
{
/* Handle Continuous reception */
HandleContinuousReception();
}
}
/**
* @brief This function configures USARTx Instance.
* @note This function is used to :
* -1- Enable GPIO clock and configures the USART pins.
* -2- NVIC Configuration for USART interrupts.
* -3- Enable the USART peripheral clock and clock source.
* -4- Configure USART functional parameters.
* -5- 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();
/* 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);
USARTx_SET_TX_GPIO_AF();
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 : Alternate function, High Speed, Push pull, Pull up */
LL_GPIO_SetPinMode(USARTx_RX_GPIO_PORT, USARTx_RX_PIN, LL_GPIO_MODE_ALTERNATE);
USARTx_SET_RX_GPIO_AF();
LL_GPIO_SetPinSpeed(USARTx_RX_GPIO_PORT, USARTx_RX_PIN, LL_GPIO_SPEED_FREQ_HIGH);
LL_GPIO_SetPinOutputType(USARTx_RX_GPIO_PORT, USARTx_RX_PIN, LL_GPIO_OUTPUT_PUSHPULL);
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) Enable USART peripheral clock and clock source ***********************/
USARTx_CLK_ENABLE();
/* (4) 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);
/* Oversampling by 16 */
/* Reset value is LL_USART_OVERSAMPLING_16 */
// LL_USART_SetOverSampling(USARTx_INSTANCE, LL_USART_OVERSAMPLING_16);
/* Set Baudrate to 115200 using APB frequency set to 100000000/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 100000000/APB_Div Hz => equal to SystemCoreClock/APB_Div
*/
LL_USART_SetBaudRate(USARTx_INSTANCE, SystemCoreClock/APB_Div, LL_USART_OVERSAMPLING_16, 115200);
/* (5) Enable USART *********************************************************/
LL_USART_Enable(USARTx_INSTANCE);
}
/**
* @brief This function prints user info on PC com port and initiates RX transfer
* @param None
* @retval None
*/
void StartReception(void)
{
/* Initializes Buffer swap mechanism :
- 2 physical buffers aRXBufferA and aRXBufferB (RX_BUFFER_SIZE length)
*/
pBufferReadyForReception = aRXBufferA;
pBufferReadyForUser = aRXBufferB;
uwNbReceivedChars = 0;
uwBufferReadyIndication = 0;
/* Print user info on PC com port */
PrintInfo(aTextInfoStart, sizeof(aTextInfoStart));
/* Clear Overrun flag, in case characters have already been sent to USART */
LL_USART_ClearFlag_ORE(USARTx_INSTANCE);
/* Enable RXNE and Error interrupts */
LL_USART_EnableIT_RXNE(USARTx_INSTANCE);
LL_USART_EnableIT_ERROR(USARTx_INSTANCE);
}
/**
* @brief This function monitors buffer filling indication and calls User callbacks when a buffer is full
* @param None
* @retval None
*/
void HandleContinuousReception(void)
{
/* Checks if Buffer full indication has been set */
if (uwBufferReadyIndication != 0)
{
/* Reset indication */
uwBufferReadyIndication = 0;
/* Call user Callback in charge of consuming data from filled buffer */
UserDataTreatment(pBufferReadyForUser, RX_BUFFER_SIZE);
}
}
/**
* @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-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 EXTI13 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 Send Txt information message on USART Tx line (to PC Com port).
* @param None
* @retval None
*/
void PrintInfo(uint8_t *String, uint32_t Size)
{
uint32_t index = 0;
uint8_t *pchar = String;
/* Send characters one per one, until last char to be sent */
for (index = 0; index < Size; index++)
{
/* Wait for TXE flag to be raised */
while (!LL_USART_IsActiveFlag_TXE(USARTx_INSTANCE))
{
}
/* Write character in Transmit Data register.
TXE flag is cleared by writing data in DR register */
LL_USART_TransmitData8(USARTx_INSTANCE, *pchar++);
}
/* Wait for TC flag to be raised for last char */
while (!LL_USART_IsActiveFlag_TC(USARTx_INSTANCE))
{
}
}
/**
* @brief Example of User callback in charge of consuming received data.
* @param None
* @retval None
*/
void UserDataTreatment(uint8_t *DataBuffer, uint32_t Size)
{
/* Display info message + buffer content on PC com port */
PrintInfo(aTextInfoSwap1, sizeof(aTextInfoSwap1));
PrintInfo(DataBuffer, Size);
PrintInfo(aTextInfoSwap2, sizeof(aTextInfoSwap2));
/* Toggle LED */
LL_GPIO_TogglePin(LED2_GPIO_PORT, LED2_PIN);
}
/**
* @brief System Clock Configuration
* The system Clock is configured as follow :
* System Clock source = PLL (HSE)
* SYSCLK(Hz) = 100000000
* HCLK(Hz) = 100000000
* AHB Prescaler = 1
* APB1 Prescaler = 2
* APB2 Prescaler = 1
* HSE Frequency(Hz) = 8000000
* PLL_M = 8
* PLL_N = 400
* PLL_P = 4
* VDD(V) = 3.3
* Main regulator output voltage = Scale1 mode
* Flash Latency(WS) = 3
* @param None
* @retval None
*/
void SystemClock_Config(void)
{
/* Enable HSE oscillator */
LL_RCC_HSE_EnableBypass();
LL_RCC_HSE_Enable();
while(LL_RCC_HSE_IsReady() != 1)
{
};
/* Set FLASH latency */
LL_FLASH_SetLatency(LL_FLASH_LATENCY_3);
/* Main PLL configuration and activation */
LL_RCC_PLL_ConfigDomain_SYS(LL_RCC_PLLSOURCE_HSE, LL_RCC_PLLM_DIV_8, 400, LL_RCC_PLLP_DIV_4);
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 */
SysTick_Config(100000000 / 1000);
/* Update CMSIS variable (which can be updated also through SystemCoreClockUpdate function) */
SystemCoreClock = 100000000;
}
/******************************************************************************/
/* 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 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)
{
uint8_t *ptemp;
/* Read Received character. RXNE flag is cleared by reading of DR register */
pBufferReadyForReception[uwNbReceivedChars++] = LL_USART_ReceiveData8(USARTx_INSTANCE);
/* Checks if Buffer full indication has been set */
if (uwNbReceivedChars >= RX_BUFFER_SIZE)
{
/* Set Buffer swap indication */
uwBufferReadyIndication = 1;
/* Swap buffers for next bytes to be received */
ptemp = pBufferReadyForUser;
pBufferReadyForUser = pBufferReadyForReception;
pBufferReadyForReception = ptemp;
uwNbReceivedChars = 0;
}
}
/**
* @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 : Clear NF Flag */
LL_USART_ClearFlag_NE(USARTx_INSTANCE);
}
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
/**
* @}
*/
/**
* @}
*/