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/**
******************************************************************************
* @file Examples_LL/USART/USART_Communication_Tx/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_Tx
* @{
*/
/* Private typedef -----------------------------------------------------------*/
/* Private define ------------------------------------------------------------*/
#if (USE_TIMEOUT == 1)
#define USART_SEND_TIMEOUT_TXE_MS 10
#define USART_SEND_TIMEOUT_TC_MS 20
#endif /* USE_TIMEOUT */
/* Private macro -------------------------------------------------------------*/
/* Private variables ---------------------------------------------------------*/
#if (USE_TIMEOUT == 1)
uint32_t Timeout = 0; /* Variable used for Timeout management */
#endif /* USE_TIMEOUT */
__IO uint8_t ubButtonPress = 0;
uint8_t ubSend = 0;
const uint8_t aStringToSend[] = "STM32F4xx USART LL API Example : TX in Polling mode\r\nConfiguration UART 115200 bps, 8 data bit/1 stop bit/No parity/No HW flow control\r\n";
/* Private function prototypes -----------------------------------------------*/
void SystemClock_Config(void);
void Configure_USART(void);
void LED_Init(void);
void LED_On(void);
void LED_Off(void);
#if (USE_TIMEOUT == 1)
void LED_Blinking(uint32_t Period);
#endif /* USE_TIMEOUT */
void UserButton_Init(void);
void WaitForUserButtonPress(void);
void BufferTransfer(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 button in EXTI mode */
UserButton_Init();
/* Configure USARTx (USART IP configuration and related GPIO initialization) */
Configure_USART();
/* Infinite loop */
while (1)
{
/* Wait for user push button press to start transfer */
WaitForUserButtonPress();
/* transfer Tx buffer to PC application */
BufferTransfer();
}
}
/**
* @brief This function configures USARTx Instance.
* @note This function is used to :
* -1- Enable GPIO clock and configures the USART pins.
* -2- Enable the USART peripheral clock and clock source.
* -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();
/* 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) Enable USART peripheral clock and clock source ***********************/
USARTx_CLK_ENABLE();
/* (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);
/* 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);
/* (4) Enable USART *********************************************************/
LL_USART_Enable(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);
}
#if (USE_TIMEOUT == 1)
/**
* @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 IO in an infinite loop */
while (1)
{
LL_GPIO_TogglePin(LED2_GPIO_PORT, LED2_PIN);
LL_mDelay(Period);
}
}
#endif /* USE_TIMEOUT */
/**
* @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)
{
}
ubSend = 0;
}
/**
* @brief Function called for achieving TX buffer sending
* @param None
* @retval None
*/
void BufferTransfer(void)
{
/* Send characters one per one, until last char to be sent */
while (ubSend < sizeof(aStringToSend))
{
#if (USE_TIMEOUT == 1)
Timeout = USART_SEND_TIMEOUT_TXE_MS;
#endif /* USE_TIMEOUT */
/* Wait for TXE flag to be raised */
while (!LL_USART_IsActiveFlag_TXE(USARTx_INSTANCE))
{
#if (USE_TIMEOUT == 1)
/* Check Systick counter flag to decrement the time-out value */
if (LL_SYSTICK_IsActiveCounterFlag())
{
if(Timeout-- == 0)
{
/* Time-out occurred. Set LED to blinking mode */
LED_Blinking(LED_BLINK_SLOW);
}
}
#endif /* USE_TIMEOUT */
}
/* If last char to be sent, clear TC flag */
if (ubSend == (sizeof(aStringToSend) - 1))
{
LL_USART_ClearFlag_TC(USARTx_INSTANCE);
}
/* Write character in Transmit Data register.
TXE flag is cleared by writing data in DR register */
LL_USART_TransmitData8(USARTx_INSTANCE, aStringToSend[ubSend++]);
}
#if (USE_TIMEOUT == 1)
Timeout = USART_SEND_TIMEOUT_TC_MS;
#endif /* USE_TIMEOUT */
/* Wait for TC flag to be raised for last char */
while (!LL_USART_IsActiveFlag_TC(USARTx_INSTANCE))
{
#if (USE_TIMEOUT == 1)
/* Check Systick counter flag to decrement the time-out value */
if (LL_SYSTICK_IsActiveCounterFlag())
{
if(Timeout-- == 0)
{
/* Time-out occurred. Set LED to blinking mode */
LED_Blinking(LED_BLINK_SLOW);
}
}
#endif /* USE_TIMEOUT */
}
ubButtonPress =0;
/* Turn LED2 On at end of transfer : Tx sequence completed successfully */
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;
}
/******************************************************************************/
/* IRQ HANDLER TREATMENT Functions */
/******************************************************************************/
/**
* @brief Function to manage Button push
* @param None
* @retval None
*/
void UserButton_Callback(void)
{
/* Update button press variable : to be checked in waiting loop in main program */
ubButtonPress = 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", file, line) */
/* Infinite loop */
while (1)
{
}
}
#endif
/**
* @}
*/
/**
* @}
*/
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