嵌入式|STM32F072从零配置工程-基于HAL库的串口UART中断配置嵌入式|c

先上一个采用串口直接传输的Demo；
此处的思路是完全采用HAL库来实现的，核心是运用HAL_UART_Transmit_IT和HAL_UART_Receive_IT两个函数来实现的，可以作为一个Demo来测试使用；
直接上代码，其串口的配置和上一章完全一致，因此忽略不计：
思路大致是将aTxStartMessage字符串发送出去，接收一个总长度为15个字符的数据到aRxBuffer中，等待接收完毕；
将接收到的aRxBuffer发送出去，等待发送完成，最后将aTxEndMessage发送出去；

uint8_t aTxStartMessage[] = "\r\n ****UART-Hyperterminal communication based on IT ****\r\n Enter 9 characters using keyboard :\r\n"; uint8_t aTxEndMessage[] = "\r\n Example Finished\r\n"; /* Buffer used for reception */ uint8_t aRxBuffer[18]; while (1) { if(HAL_UART_Transmit_IT(&huart2, (uint8_t*)aTxStartMessage, sizeof(aTxStartMessage)) != HAL_OK) { while(1); } if(HAL_UART_Receive_IT(&huart2, (uint8_t*)aRxBuffer, 15) != HAL_OK) { while(1); } while(HAL_UART_GetState(&huart2) != HAL_UART_STATE_READY); if(HAL_UART_Transmit_IT(&huart2, (uint8_t*)aRxBuffer, 15) != HAL_OK) { while(1); } while(HAL_UART_GetState(&huart2) != HAL_UART_STATE_READY); if(HAL_UART_Transmit_IT(&huart2, (uint8_t*)aTxEndMessage, sizeof(aTxEndMessage)) != HAL_OK) { while(1); } while(HAL_UART_GetState(&huart2) != HAL_UART_STATE_READY); }

【嵌入式|STM32F072从零配置工程-基于HAL库的串口UART中断配置】

接下来是也是一个Demo，采用HAL库来实现串口收发中断，思路和C一个一个接收字符然后发送出去是相似的，只不过是采用串口IT中断来实现；
串口的配置不变，因此在此忽略不计；

uint8_t aRxBuffer; int main(void) { HAL_Init(); SystemClock_Config(); MX_GPIO_Init(); MX_USART2_UART_Init(); HAL_UART_Receive_IT(&huart3, &aRxBuffer, 1); while (1) {} }void USART2_IRQHandler(void) { HAL_UART_IRQHandler(&huart2); }void HAL_UART_RxCpltCallback(UART_HandleTypeDef *UartHandler) { HAL_UART_Transmit(&huart3, &aRxBuffer, 1, 0); HAL_UART_Receive_IT(&huart3, &aRxBuffer, 1); }

简要分析以下这个程序的思路：
开头采用HAL_UART_Receive_IT()这个函数和目的不是为了接收数据，而是通过里面的配置开启中断，核心在SET_BIT()这两句话中（开启EIE、PEIE和RXNEIE这三个中断）；

HAL_StatusTypeDef HAL_UART_Receive_IT(UART_HandleTypeDef *huart, uint8_t *pData, uint16_t Size) { /* Check that a Rx process is not already ongoing */ if(huart->RxState == HAL_UART_STATE_READY) { if((pData =https://www.it610.com/article/= NULL ) || (Size == 0U)) { return HAL_ERROR; } /* In case of 9bits/No Parity transfer, pData buffer provided as input paramter should be aligned on a u16 frontier, as data to be received from RDR will be handled through a u16 cast. */ if ((huart->Init.WordLength == UART_WORDLENGTH_9B) && (huart->Init.Parity == UART_PARITY_NONE)) { if((((uint32_t)pData)&1U) != 0U) { returnHAL_ERROR; } }/* Process Locked */ __HAL_LOCK(huart); huart->pRxBuffPtr = pData; huart->RxXferSize = Size; huart->RxXferCount = Size; /* Computation of UART mask to apply to RDR register */ UART_MASK_COMPUTATION(huart); huart->ErrorCode = HAL_UART_ERROR_NONE; huart->RxState = HAL_UART_STATE_BUSY_RX; /* Process Unlocked */ __HAL_UNLOCK(huart); /* Enable the UART Error Interrupt: (Frame error, noise error, overrun error) */ SET_BIT(huart->Instance->CR3, USART_CR3_EIE); /* Enable the UART Parity Error and Data Register not empty Interrupts */ SET_BIT(huart->Instance->CR1, USART_CR1_PEIE | USART_CR1_RXNEIE); return HAL_OK; } else { return HAL_BUSY; } }

接收数据的过程可以从中断中了解：
当接收到数据后判断ISR寄存器中RXNE中断标志是否置位和CR1寄存器中RXNE中断使能是否开启，然后进入到接收处理函数UART_Receive_IT()中；
在UART_Receive_IT()中，关闭EIE、PEIE和RXNE中断，同时调用回调函数HAL_UART_RxCpltCallback()；

void USART2_IRQHandler(void) { HAL_UART_IRQHandler(&huart2); }void HAL_UART_IRQHandler(UART_HandleTypeDef *huart) {/* If some errors occur */ cr3its = READ_REG(huart->Instance->CR3); if((errorflags != RESET) && (((cr3its & USART_CR3_EIE) != RESET) || ((cr1its & (USART_CR1_RXNEIE | USART_CR1_PEIE)) != RESET)) ) {/* Call UART Error Call back function if need be --------------------------*/ if(huart->ErrorCode != HAL_UART_ERROR_NONE) { /* UART in mode Receiver ---------------------------------------------------*/ if(((isrflags & USART_ISR_RXNE) != RESET) && ((cr1its & USART_CR1_RXNEIE) != RESET)) { UART_Receive_IT(huart); } } return; } /* End if some error occurs */ }HAL_StatusTypeDef UART_Receive_IT(UART_HandleTypeDef *huart) { /* Check that a Rx process is ongoing */ if(huart->RxState == HAL_UART_STATE_BUSY_RX) { if(--huart->RxXferCount == 0U) { /* Disable the UART Parity Error Interrupt and RXNE interrupt*/ CLEAR_BIT(huart->Instance->CR1, (USART_CR1_RXNEIE | USART_CR1_PEIE)); /* Disable the UART Error Interrupt: (Frame error, noise error, overrun error) */ CLEAR_BIT(huart->Instance->CR3, USART_CR3_EIE); /* Rx process is completed, restore huart->RxState to Ready */ huart->RxState = HAL_UART_STATE_READY; HAL_UART_RxCpltCallback(huart); return HAL_OK; } } }

在主函数中执行重写的回调函数：
将接收到的一个字符发送出去，同时开启接收中断准备接收下一个字符；

void HAL_UART_RxCpltCallback(UART_HandleTypeDef *UartHandler) { HAL_UART_Transmit(&huart3, &aRxBuffer, 1, 0); HAL_UART_Receive_IT(&huart3, &aRxBuffer, 1); }

其实现的功能可以和以下C语言实现的相似：