static void MX_USART1_UART_Init(void)
{
huart1.Instance = USART1;
huart1.Init.BaudRate = 115200;
huart1.Init.WordLength = UART_WORDLENGTH_8B;
huart1.Init.StopBits = UART_STOPBITS_1;
huart1.Init.Parity = UART_PARITY_NONE;
huart1.Init.Mode = UART_MODE_TX_RX;
huart1.Init.HwFlowCtl = UART_HWCONTROL_NONE;
huart1.Init.OverSampling = UART_OVERSAMPLING_16;
if (HAL_UART_Init(&huart1) != HAL_OK)
{
Error_Handler();
}
}
前面是串口的一些配置。
HAL_UART_Init(&huart1)是真正的初始化函数。
初始化函数定义在\Drivers\Stm32F1xx_HAL_Drivers\Src\stm32f1xx_hal_uart.c 中。
HAL_StatusTypeDef HAL_UART_Init(UART_HandleTypeDef *huart)
{
/* Check the UART handle allocation */
if (huart == NULL)
{
return HAL_ERROR;
}
/* Check the parameters */
if (huart->Init.HwFlowCtl != UART_HWCONTROL_NONE) //硬件流控制吗
{
/* The hardware flow control is available only for USART1, USART2 and USART3 */
assert_param(IS_UART_HWFLOW_INSTANCE(huart->Instance));
assert_param(IS_UART_HARDWARE_FLOW_CONTROL(huart->Init.HwFlowCtl));
}
else
{
assert_param(IS_UART_INSTANCE(huart->Instance));
}
assert_param(IS_UART_WORD_LENGTH(huart->Init.WordLength)); //检查数据位
#if defined(USART_CR1_OVER8)
assert_param(IS_UART_OVERSAMPLING(huart->Init.OverSampling));
#endif /* USART_CR1_OVER8 */
if (huart->gState == HAL_UART_STATE_RESET)
{
/* Allocate lock resource and initialize it */
huart->Lock = HAL_UNLOCKED;
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
UART_InitCallbacksToDefault(huart);
if (huart->MspInitCallback == NULL)
{
huart->MspInitCallback = HAL_UART_MspInit;
}
/* Init the low level hardware */
huart->MspInitCallback(huart);
#else
/* Init the low level hardware : GPIO, CLOCK */
HAL_UART_MspInit(huart); //--->>>跳转到\Src\stm32f1xx_hal_msp.c
//在这个函数中初始化了时钟、GPIO、中断
#endif /* (USE_HAL_UART_REGISTER_CALLBACKS) */
}
huart->gState = HAL_UART_STATE_BUSY;
/* Disable the peripheral */
__HAL_UART_DISABLE(huart);
/* Set the UART Communication parameters */
UART_SetConfig(huart); //真正配置寄存器
/* In asynchronous mode, the following bits must be kept cleared:
- LINEN and CLKEN bits in the USART_CR2 register,
- SCEN, HDSEL and IREN bits in the USART_CR3 register.*/
CLEAR_BIT(huart->Instance->CR2, (USART_CR2_LINEN | USART_CR2_CLKEN));
CLEAR_BIT(huart->Instance->CR3, (USART_CR3_SCEN | USART_CR3_HDSEL | USART_CR3_IREN));
/* Enable the peripheral */
__HAL_UART_ENABLE(huart); //使能串口
/* Initialize the UART state */
huart->ErrorCode = HAL_UART_ERROR_NONE;
huart->gState = HAL_UART_STATE_READY;
huart->RxState = HAL_UART_STATE_READY;
return HAL_OK;
}
//中断服务函数，在\Src\stm32f1xx_it.c中定义
void USART1_IRQHandler(void)
{
/* USER CODE BEGIN USART1_IRQn 0 */
/* USER CODE END USART1_IRQn 0 */
HAL_UART_IRQHandler(&huart1);
/* USER CODE BEGIN USART1_IRQn 1 */
/* USER CODE END USART1_IRQn 1 */
}
//中断服务函数，在\Drivers\Stm32F1xx_HAL_Drivers\Src\stm32f1xx_hal_uart.c中给定义好了
void HAL_UART_IRQHandler(UART_HandleTypeDef *huart)
{
uint32_t isrflags = READ_REG(huart->Instance->SR); //读取SR寄存器
uint32_t cr1its = READ_REG(huart->Instance->CR1); //读取CR1寄存器
uint32_t cr3its = READ_REG(huart->Instance->CR3); //读取CR3寄存器
uint32_t errorflags = 0x00U;
uint32_t dmarequest = 0x00U;
/* If no error occurs */
errorflags = (isrflags & (uint32_t)(USART_SR_PE | USART_SR_FE | USART_SR_ORE | USART_SR_NE));
//如果出现错误:PE校验错误;FE: 帧错误;ORE：过载错误;NE: 噪声错误
if (errorflags == RESET) //RESET=0 ;如果没错误
{
/* UART in mode Receiver -------------------------------------------------*/
if (((isrflags & USART_SR_RXNE) != RESET) && ((cr1its & USART_CR1_RXNEIE) != RESET))
//RXNE：读数据寄存器非空 ,0：数据没有收到；1：收到数据，可以读出。
//RXNEIE：接收缓冲区非空中断使能 (RXNE interrupt enable) 该位由软件设置或清除。
//0：禁止产生中断；
//1：当USART_SR中的ORE或者RXNE为’1’时，产生USART中断。
{
UART_Receive_IT(huart); //处理函数
return;
}
}
/* If some errors occur */
/*如果有错误发生*/
if ((errorflags != RESET) && (((cr3its & USART_CR3_EIE) != RESET) || ((cr1its & (USART_CR1_RXNEIE | USART_CR1_PEIE)) != RESET)))
//EIE：错误中断使能 (Error interrupt enable)
//在多缓冲区通信模式下，当有帧错误、过载或者噪声错误时(USART_SR中的FE=1，或者
//ORE=1，或者NE=1)产生中断。
//0：禁止中断；
//1：只要USART_CR3中的DMAR=1，并且USART_SR中的FE=1，或者ORE=1，或者NE=1，
//则产生中断
//RXNEIE：接收缓冲区非空中断使能 (RXNE interrupt enable)
//该位由软件设置或清除。
//0：禁止产生中断；
//1：当USART_SR中的ORE或者RXNE为’1’时，产生USART中断。
// PEIE： PE中断使能 (PE interrupt enable)
//该位由软件设置或清除。
//0：禁止产生中断；
//1：当USART_SR中的PE为’1’时，产生USART中断
{
/* UART parity error interrupt occurred ----------------------------------*/
if (((isrflags & USART_SR_PE) != RESET) && ((cr1its & USART_CR1_PEIE) != RESET))
{
huart->ErrorCode |= HAL_UART_ERROR_PE;
}
/* UART noise error interrupt occurred -----------------------------------*/
if (((isrflags & USART_SR_NE) != RESET) && ((cr3its & USART_CR3_EIE) != RESET))
{
huart->ErrorCode |= HAL_UART_ERROR_NE;
}
/* UART frame error interrupt occurred -----------------------------------*/
if (((isrflags & USART_SR_FE) != RESET) && ((cr3its & USART_CR3_EIE) != RESET))
{
huart->ErrorCode |= HAL_UART_ERROR_FE;
}
/* UART Over-Run interrupt occurred --------------------------------------*/
if (((isrflags & USART_SR_ORE) != RESET) && ((cr3its & USART_CR3_EIE) != RESET))
{
huart->ErrorCode |= HAL_UART_ERROR_ORE;
}
/* Call UART Error Call back function if need be --------------------------*/
if (huart->ErrorCode != HAL_UART_ERROR_NONE)
{
/* UART in mode Receiver -----------------------------------------------*/
if (((isrflags & USART_SR_RXNE) != RESET) && ((cr1its & USART_CR1_RXNEIE) != RESET))
{
UART_Receive_IT(huart);
}
/* If Overrun error occurs, or if any error occurs in DMA mode reception,
consider error as blocking */
dmarequest = HAL_IS_BIT_SET(huart->Instance->CR3, USART_CR3_DMAR);
if (((huart->ErrorCode & HAL_UART_ERROR_ORE) != RESET) || dmarequest)
{
/* Blocking error : transfer is aborted
Set the UART state ready to be able to start again the process,
Disable Rx Interrupts, and disable Rx DMA request, if ongoing */
UART_EndRxTransfer(huart);
/* Disable the UART DMA Rx request if enabled */
if (HAL_IS_BIT_SET(huart->Instance->CR3, USART_CR3_DMAR))
{
CLEAR_BIT(huart->Instance->CR3, USART_CR3_DMAR);
/* Abort the UART DMA Rx channel */
if (huart->hdmarx != NULL)
{
/* Set the UART DMA Abort callback :
will lead to call HAL_UART_ErrorCallback() at end of DMA abort procedure */
huart->hdmarx->XferAbortCallback = UART_DMAAbortOnError;
if (HAL_DMA_Abort_IT(huart->hdmarx) != HAL_OK)
{
/* Call Directly XferAbortCallback function in case of error */
huart->hdmarx->XferAbortCallback(huart->hdmarx);
}
}
else
{
/* Call user error callback */
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
/*Call registered error callback*/
huart->ErrorCallback(huart);
#else
/*Call legacy weak error callback*/
HAL_UART_ErrorCallback(huart);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */
}
}
else
{
/* Call user error callback */
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
/*Call registered error callback*/
huart->ErrorCallback(huart);
#else
/*Call legacy weak error callback*/
HAL_UART_ErrorCallback(huart);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */
}
}
else
{
/* Non Blocking error : transfer could go on.
Error is notified to user through user error callback */
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
/*Call registered error callback*/
huart->ErrorCallback(huart);
#else
/*Call legacy weak error callback*/
HAL_UART_ErrorCallback(huart);
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */
huart->ErrorCode = HAL_UART_ERROR_NONE;
}
}
return;
} /* End if some error occurs */
/* UART in mode Transmitter ------------------------------------------------*/
if (((isrflags & USART_SR_TXE) != RESET) && ((cr1its & USART_CR1_TXEIE) != RESET))
{
UART_Transmit_IT(huart);
return;
}
/* UART in mode Transmitter end --------------------------------------------*/
if (((isrflags & USART_SR_TC) != RESET) && ((cr1its & USART_CR1_TCIE) != RESET))
{
UART_EndTransmit_IT(huart);
return;
}
}
//中断接收
/**
* @brief Receives an amount of data in non blocking mode
* @param huart Pointer to a UART_HandleTypeDef structure that contains
* the configuration information for the specified UART module.
* @retval HAL status
*/
static HAL_StatusTypeDef UART_Receive_IT(UART_HandleTypeDef *huart)
{
uint16_t *tmp;
/* Check that a Rx process is ongoing */
if (huart->RxState == HAL_UART_STATE_BUSY_RX) //如果忙
{
if (huart->Init.WordLength == UART_WORDLENGTH_9B) // 1：一个起始位， 9个数据位， n个停止位。
{
tmp = (uint16_t *) huart->pRxBuffPtr; //tmp =pRxBuffPtr,接收缓冲器
if (huart->Init.Parity == UART_PARITY_NONE)//无奇偶校验
{
*tmp = (uint16_t)(huart->Instance->DR & (uint16_t)0x01FF);
huart->pRxBuffPtr += 2U;
}
else
{
*tmp = (uint16_t)(huart->Instance->DR & (uint16_t)0x00FF);
huart->pRxBuffPtr += 1U;
}
}
else //数据位8位7位小于等于8位....
{
if (huart->Init.Parity == UART_PARITY_NONE)
{
*huart->pRxBuffPtr++ = (uint8_t)(huart->Instance->DR & (uint8_t)0x00FF);//没有奇偶校验，全部为数据
}
else
{
*huart->pRxBuffPtr++ = (uint8_t)(huart->Instance->DR & (uint8_t)0x007F);//有奇偶校验，除掉第8位，取得7位数据
}
}
if (--huart->RxXferCount == 0U)
{
/* Disable the UART Data Register not empty Interrupt */
__HAL_UART_DISABLE_IT(huart, UART_IT_RXNE); //关闭中断
/* Disable the UART Parity Error Interrupt */
__HAL_UART_DISABLE_IT(huart, UART_IT_PE); //关闭中断
/* Disable the UART Error Interrupt: (Frame error, noise error, overrun error) */
__HAL_UART_DISABLE_IT(huart, UART_IT_ERR); //关闭中断
/* Rx process is completed, restore huart->RxState to Ready */
huart->RxState = HAL_UART_STATE_READY; //接收完成
#if (USE_HAL_UART_REGISTER_CALLBACKS == 1)
/*Call registered Rx complete callback*/
huart->RxCpltCallback(huart);
#else
/*Call legacy weak Rx complete callback*/
HAL_UART_RxCpltCallback(huart); //中断服务函数
#endif /* USE_HAL_UART_REGISTER_CALLBACKS */
return HAL_OK;
}
return HAL_OK;
}
else
{
return HAL_BUSY;
}
}
__weak void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart) //本函数是__weak ，需要重写。
{
/* Prevent unused argument(s) compilation warning */
UNUSED(huart);
/* NOTE: This function should not be modified, when the callback is needed,
the HAL_UART_RxCpltCallback could be implemented in the user file
*/
}
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