STM32CubeMX

2024-07-08 14:41| 来源: 网络整理| 查看: 265

CubeMx中HAL库函数的调用不同于库函数调用，在学习CubeMx串口通信时，不理解HAL库中的回调函数是怎么被调用的，于是查看每个的定义，参考其他人写的博客，总算弄明白了HAL库中断调用与库函数不同之处。写下这篇博客一是加深自己的理解，二是希望对不理解HAL库中回调函数调用机制的朋友有所帮助。

工程代码参考：【STM32】-CubeMX-HAL库-UART-串口通信-STM32F103C8T6-收发测试

在库函数中，UART串口发生中断时，我们直接将业务代码写在void USART1_IRQHandler(void)中，如下图：

void USART1_IRQHandler(void) //串口1中断服务程序 { u8 Res; if(USART_GetITStatus(USART1, USART_IT_RXNE) != RESET) //接收中断(接收到的数据必须是0x0d 0x0a结尾) { Res =USART_ReceiveData(USART1); //读取接收到的数据 if((USART_RX_STA&0x8000)==0)//接收未完成 { if(USART_RX_STA&0x4000)//接收到了0x0d { if(Res!=0x0a)USART_RX_STA=0;//接收错误,重新开始 else USART_RX_STA|=0x8000; //接收完成了 } else //还没收到0X0D { if(Res==0x0d)USART_RX_STA|=0x4000; else { USART_RX_BUF[USART_RX_STA&0X3FFF]=Res ; USART_RX_STA++; if(USART_RX_STA>(USART_REC_LEN-1))USART_RX_STA=0;//接收数据错误,重新开始接收 } } } } } 对于CubeMX生成的代码，USART1_IRQHandler(void)函数为了提高中断效率采用了回调机制。（业务代码可以等中断关闭了再去处理，这样中断处理不会占用太多时间影响程序的执行效率）

USART1_IRQHandler(void)函数中只调用了HAL_UART_IRQHandler(&huart1)（可以在STM32f1xx_it.c中找到），参数为uart1的句柄huart1，句柄可以理解为通过huart1访问到uart1的各种寄存器和数据类型，不理解的话，可以去看UART_HandleTypeDef结构体的定义。

在HAL_UART_IRQHandler(UART_HandleTypeDef *huart)函数内又调用了UART_Receive_IT(huart);（回调函数在这个函数中被调用）看注释理解该函数的作用

static HAL_StatusTypeDef UART_Receive_IT(UART_HandleTypeDef *huart) { //用这个指针指向我们用于接收数据的变量或数组，在收发测试例程中定义的是char Res uint8_t *pdata8bits; uint16_t *pdata16bits; /* Check that a Rx process is ongoing */ if (huart->RxState == HAL_UART_STATE_BUSY_RX) { if ((huart->Init.WordLength == UART_WORDLENGTH_9B) && (huart->Init.Parity == UART_PARITY_NONE)) { pdata8bits = NULL; pdata16bits = (uint16_t *) huart->pRxBuffPtr;//指向Res,相当于pdata16bits=&Res //具体原因参考HAL_UART_Receive_IT(&huart1, &Res, 1); *pdata16bits = (uint16_t)(huart->Instance->DR & (uint16_t)0x01FF); huart->pRxBuffPtr += 2U; } else { pdata8bits = (uint8_t *) huart->pRxBuffPtr;//指向Res,相当于pdata8bits=&Res pdata16bits = NULL; if ((huart->Init.WordLength == UART_WORDLENGTH_9B) || ((huart->Init.WordLength == UART_WORDLENGTH_8B) && (huart->Init.Parity == UART_PARITY_NONE))) { //指针操作相当于Res= (uint8_t)(huart->Instance->DR & (uint8_t)0x00FF); *pdata8bits = (uint8_t)(huart->Instance->DR & (uint8_t)0x00FF); } else { //指针操作相当于Res= (uint8_t)(huart->Instance->DR & (uint8_t)0x00FF); *pdata8bits = (uint8_t)(huart->Instance->DR & (uint8_t)0x007F); } huart->pRxBuffPtr += 1U; } if (--huart->RxXferCount == 0U)//关闭中断，准备回调，对串口接收到的数据保存 { /* Disable the UART Data Register not empty Interrupt */ __HAL_UART_DISABLE_IT(huart, UART_IT_RXNE); /* Disable the UART Parity Error Interrupt */ __HAL_UART_DISABLE_IT(huart, UART_IT_PE); /* Disable the UART Error Interrupt: (Frame error, noise error, overrun error) */ __HAL_UART_DISABLE_IT(huart, UART_IT_ERR); /* Rx process is completed, restore huart->RxState to Ready */ huart->RxState = HAL_UART_STATE_READY; /* Check current reception Mode : If Reception till IDLE event has been selected : */ if (huart->ReceptionType == HAL_UART_RECEPTION_TOIDLE) { /* Set reception type to Standard */ huart->ReceptionType = HAL_UART_RECEPTION_STANDARD; /* Disable IDLE interrupt */ CLEAR_BIT(huart->Instance->CR1, USART_CR1_IDLEIE); /* Check if IDLE flag is set */ if (__HAL_UART_GET_FLAG(huart, UART_FLAG_IDLE)) { /* Clear IDLE flag in ISR */ __HAL_UART_CLEAR_IDLEFLAG(huart); } #if (USE_HAL_UART_REGISTER_CALLBACKS == 1) /*Call registered Rx Event callback*/ huart->RxEventCallback(huart, huart->RxXferSize); #else /*Call legacy weak Rx Event callback*/ HAL_UARTEx_RxEventCallback(huart, huart->RxXferSize); #endif } else { /* Standard reception API called */ #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);//正常情况下会执行这一条语句 //我们可以自己定义这个函数内部的具体操作 #endif /* USE_HAL_UART_REGISTER_CALLBACKS */ } return HAL_OK; } return HAL_OK; } else { return HAL_BUSY; } } 表格中左右两边的操作为什么等价呢？ pdata8bits = (uint8_t *) huart->pRxBuffPtr;pdata8bits=&Res *pdata8bits = (uint8_t)(huart->Instance->DR & (uint8_t)0x00FF);Res= (uint8_t)(huart->Instance->DR & (uint8_t)0x00FF); 可以从UART_Start_Receive_IT函数中找到答案（UART_Start_Receive_IT被main函数中的HAL_UART_Receive_IT调用） //函数参数相当于（&huart1, &Res, 1） HAL_StatusTypeDef UART_Start_Receive_IT(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size) { //函数参数相当于（&huart1, &Res, 1） huart->pRxBuffPtr = pData;//pData==&Res //在UART_Receive_IT函数中 pdata8bits = (uint8_t *) huart->pRxBuffPtr; //pdata8bits=&Res，其他都是同理，如果不理解，需要回顾一下指针操作。 huart->RxXferSize = Size;//Size==1 huart->RxXferCount = Size; huart->ErrorCode = HAL_UART_ERROR_NONE; huart->RxState = HAL_UART_STATE_BUSY_RX; /* Process Unlocked */ __HAL_UNLOCK(huart); /* Enable the UART Parity Error Interrupt */ __HAL_UART_ENABLE_IT(huart, UART_IT_PE); /* Enable the UART Error Interrupt: (Frame error, noise error, overrun error) */ __HAL_UART_ENABLE_IT(huart, UART_IT_ERR); /* Enable the UART Data Register not empty Interrupt */ __HAL_UART_ENABLE_IT(huart, UART_IT_RXNE); return HAL_OK; } 回调函数： void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart)//自定义回调函数在UART_Receive_IT()中调用 { //判断是哪个串口触发的中断 huart1.Instance = USART1;定义在MX_USART1_UART_Init中 if(huart==&huart1)//huart ->Instance == USART1两种判断条件等价 { if((UART1_RX_STA & 0x8000)==0)//接收未完成&位运算符 &&短路与判断 { if(UART1_RX_STA & 0x4000)//接收到 \r { if(Res==0x0a)//下一个必须是接收 \n UART1_RX_STA|=0x8000; else UART1_RX_STA=0; } else //未接收到\r { if(Res==0x0d)//Receive \r { UART1_RX_STA|=0x4000; } else { UART1_RX_Buffer[UART1_RX_STA&0X3FFF]=Res; UART1_RX_STA++; if(UART1_RX_STA>UART1_REC_LEN-1) UART1_RX_STA=0;//如果接收数据大于200Byte 重新开始接收 } } } HAL_UART_Receive_IT(&huart1, &Res, 1);//完成一次接受，再此开启中断 } } 如果我们自己没有定义回调函数的话，系统会调用自带的回调函数，函数类型为__weak，表示弱定义如果用户自己定义了函数就优先调用用户定义的回调函数 __weak void HAL_UART_RxCpltCallback(UART_HandleTypeDef *huart) { /* 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 */ } 如果对你有帮助，请点个赞再走，Respect！

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