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/**
******************************************************************************
* @file Examples_LL/USART/USART_HardwareFlowControl/Src/main.c
* @author MCD Application Team
* @brief This example describes how to transfer bytes from/to an USART peripheral
* to/from a PC UART with HW FLow Control enabled,
* through 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_HardwareFlowControl
* @{
*/
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
__IO uint8_t ubButtonPress = 0;
/**
* @brief Variables used for character transmission to PC Com port
*/
__IO uint8_t ubSend = 0;
const uint8_t aStringToSend[] = "STM32F4xx USART LL API Example : TX/RX in IT mode\r\nConfiguration UART 115200 bps, 8 data bit/1 stop bit/No parity/HW flow control enabled.\r\nEnter any character (S or s will end program).\r\n";
uint8_t ubSizeToSend = sizeof(aStringToSend);
/**
* @brief Variables used for character reception from PC Com port
*/
__IO uint8_t ubFinalCharReceived = 0;
__IO uint32_t ubReceivedChar;
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
void Configure_USART1(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);
/* 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 USART1 (USART IP configuration and related GPIO initialization) */
Configure_USART1();
/* 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 USART1.
* @note This function is used to :
* -1- Enable GPIO clock and configures the USART1 pins.
* -2- NVIC Configuration for USART1 interrupts.
* -3- Enable the USART1 peripheral clock and clock source.
* -4- Configure USART1 functional parameters.
* -5- Enable USART1.
* @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_USART1(void)
{
/* (1) Enable GPIO clock and configures the USART1 pins *********************/
/* (TX on PA.9, RX on PA.10) *********************/
/* (CTS on PA.11, RTS on PA.12) *********************/
/* Enable the peripheral clock of GPIOA */
LL_AHB1_GRP1_EnableClock(LL_AHB1_GRP1_PERIPH_GPIOA);
/* Configure TX Pin as : Alternate function, High Speed, PushPull, Pull up */
LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_9, LL_GPIO_MODE_ALTERNATE);
LL_GPIO_SetAFPin_8_15(GPIOA, LL_GPIO_PIN_9, LL_GPIO_AF_7);
LL_GPIO_SetPinSpeed(GPIOA, LL_GPIO_PIN_9, LL_GPIO_SPEED_FREQ_HIGH);
LL_GPIO_SetPinOutputType(GPIOA, LL_GPIO_PIN_9, LL_GPIO_OUTPUT_PUSHPULL);
LL_GPIO_SetPinPull(GPIOA, LL_GPIO_PIN_9, LL_GPIO_PULL_UP);
/* Configure RX Pin as : Alternate function, High Speed, PushPull, Pull up */
LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_10, LL_GPIO_MODE_ALTERNATE);
LL_GPIO_SetAFPin_8_15(GPIOA, LL_GPIO_PIN_10, LL_GPIO_AF_7);
LL_GPIO_SetPinSpeed(GPIOA, LL_GPIO_PIN_10, LL_GPIO_SPEED_FREQ_HIGH);
LL_GPIO_SetPinOutputType(GPIOA, LL_GPIO_PIN_10, LL_GPIO_OUTPUT_PUSHPULL);
LL_GPIO_SetPinPull(GPIOA, LL_GPIO_PIN_10, LL_GPIO_PULL_UP);
/* Configure CTS Pin as : Alternate function, High Speed, OpenDrain, Pull up */
LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_11, LL_GPIO_MODE_ALTERNATE);
LL_GPIO_SetAFPin_8_15(GPIOA, LL_GPIO_PIN_11, LL_GPIO_AF_7);
LL_GPIO_SetPinSpeed(GPIOA, LL_GPIO_PIN_11, LL_GPIO_SPEED_FREQ_HIGH);
LL_GPIO_SetPinOutputType(GPIOA, LL_GPIO_PIN_11, LL_GPIO_OUTPUT_OPENDRAIN);
LL_GPIO_SetPinPull(GPIOA, LL_GPIO_PIN_11, LL_GPIO_PULL_UP);
/* Configure RTS Pin as : Alternate function, High Speed, OpenDrain, Pull up */
LL_GPIO_SetPinMode(GPIOA, LL_GPIO_PIN_12, LL_GPIO_MODE_ALTERNATE);
LL_GPIO_SetAFPin_8_15(GPIOA, LL_GPIO_PIN_12, LL_GPIO_AF_7);
LL_GPIO_SetPinSpeed(GPIOA, LL_GPIO_PIN_12, LL_GPIO_SPEED_FREQ_HIGH);
LL_GPIO_SetPinOutputType(GPIOA, LL_GPIO_PIN_12, LL_GPIO_OUTPUT_OPENDRAIN);
LL_GPIO_SetPinPull(GPIOA, LL_GPIO_PIN_12, LL_GPIO_PULL_UP);
/* (2) NVIC Configuration for USART1 interrupts */
/* - Set priority for USART1_IRQn */
/* - Enable USART1_IRQn */
NVIC_SetPriority(USART1_IRQn, 0);
NVIC_EnableIRQ(USART1_IRQn);
/* (3) Enable the USART1 peripheral clock and clock source ****************/
LL_APB2_GRP1_EnableClock(LL_APB2_GRP1_PERIPH_USART1);
/* (4) Configure USART1 functional parameters ********************************/
/* Disable USART1 prior modifying configuration registers */
/* Note: Commented as corresponding to Reset value */
// LL_USART_Disable(USART1);
/* TX/RX direction */
LL_USART_SetTransferDirection(USART1, LL_USART_DIRECTION_TX_RX);
/* 8 data bit, 1 start bit, 1 stop bit, no parity */
LL_USART_ConfigCharacter(USART1, LL_USART_DATAWIDTH_8B, LL_USART_PARITY_NONE, LL_USART_STOPBITS_1);
/* Enable CTS/RTS Hardware Flow Control */
LL_USART_SetHWFlowCtrl(USART1, LL_USART_HWCONTROL_RTS_CTS);
/* Oversampling by 16 */
/* Reset value is LL_USART_OVERSAMPLING_16 */
// LL_USART_SetOverSampling(USART1, LL_USART_OVERSAMPLING_16);
/* Set Baudrate to 115200 using APB frequency set to 100000000 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 Hz => equal to SystemCoreClock
*/
LL_USART_SetBaudRate(USART1, SystemCoreClock, LL_USART_OVERSAMPLING_16, 115200);
/* (5) Enable USART *********************************************************/
LL_USART_Enable(USART1);
/* Enable RXNE and Error interrupts */
LL_USART_EnableIT_RXNE(USART1);
LL_USART_EnableIT_ERROR(USART1);
}
/**
* @brief This function initiates TX transfer
* @param None
* @retval None
*/
void StartTransfers(void)
{
/* Start transfer only if not already ongoing */
if (ubSend == 0)
{
/* Start USART transmission : Will initiate TXE interrupt after DR register is empty */
LL_USART_TransmitData8(USART1, aStringToSend[ubSend++]);
/* Enable TXE interrupt */
LL_USART_EnableIT_TXE(USART1);
}
}
/**
* @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 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 Wait end of transfer and check if received Data are well.
* @param None
* @retval None
*/
void WaitAndCheckEndOfTransfer(void)
{
/* Wait end of reception from USART1 */
while (ubFinalCharReceived != 1)
{
}
/* Turn On Led indicating final character has been received */
LED_On();
}
/**
* @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 for achieving next TX Byte sending
* @param None
* @retval None
*/
void USART_TXEmpty_Callback(void)
{
if(ubSend == (ubSizeToSend - 1))
{
/* Disable TXE interrupt */
LL_USART_DisableIT_TXE(USART1);
/* Enable TC interrupt */
LL_USART_EnableIT_TC(USART1);
}
/* Fill DR with a new char */
LL_USART_TransmitData8(USART1, aStringToSend[ubSend++]);
}
/**
* @brief Function called at completion of last byte transmission
* @param None
* @retval None
*/
void USART_CharTransmitComplete_Callback(void)
{
if(ubSend == sizeof(aStringToSend))
{
ubSend = 0;
/* Disable TC interrupt */
LL_USART_DisableIT_TC(USART1);
}
}
/**
* @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(USART1);
/* Check if received value is corresponding to specific one : S or s */
if ((received_char == 'S') || (received_char == 's'))
{
ubFinalCharReceived = 1;
/* Disable RXNE interrupt */
LL_USART_DisableIT_RXNE(USART1);
}
/* Echo received character on TX */
LL_USART_TransmitData8(USART1, 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 USART1_IRQn */
NVIC_DisableIRQ(USART1_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(USART1, SR);
if (sr_reg & LL_USART_SR_NE)
{
/* case Noise Error flag is raised : Clear NF Flag */
LL_USART_ClearFlag_NE(USART1);
}
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
/**
* @}
*/
/**
* @}
*/