#include "usart3.h" uint8_t Usart3_RxPacket[10]; //定义接收数据包数组 uint8_t Usart3_RxFlag; //定义接收数据包标志位 uint8_t Usart3_seshig; void Uart3_Init(void) { //GPIO端口设置 GPIO_InitTypeDef GPIO_InitStructure; USART_InitTypeDef USART_InitStructure; NVIC_InitTypeDef NVIC_InitStructure; RCC_APB1PeriphClockCmd(RCC_APB1Periph_USART3, ENABLE); //使能Usart3，GPIOA时钟 RCC_APB2PeriphClockCmd(RCC_APB2Periph_GPIOB, ENABLE); //使能GPIOA时钟 //Usart3_TX GPIOB.10 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10; //PA2 GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz; GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP; //复用推挽输出 GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化GPIOB.10 //Usart3_RX GPIOB.11初始化 GPIO_InitStructure.GPIO_Pin = GPIO_Pin_11;//PA3 GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;//浮空输入 GPIO_Init(GPIOB, &GPIO_InitStructure);//初始化GPIOB.11 //Usart3 NVIC 配置 NVIC_InitStructure.NVIC_IRQChannel = USART3_IRQn; NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;//抢占优先级 NVIC_InitStructure.NVIC_IRQChannelSubPriority = 2; //子优先级4 NVIC_InitStructure.NVIC_IRQChannelCmd = ENABLE; //IRQ通道使能 NVIC_Init(&NVIC_InitStructure); //根据指定的参数初始化VIC寄存器 //USART 初始化设置 USART_InitStructure.USART_BaudRate = 9600;//串口波特率 USART_InitStructure.USART_WordLength = USART_WordLength_8b;//字长为8位数据格式 USART_InitStructure.USART_StopBits = USART_StopBits_1;//一个停止位 USART_InitStructure.USART_Parity = USART_Parity_No;//无奇偶校验位 USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;//无硬件数据流控制 USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx; //收发模式 USART_Init(USART3, &USART_InitStructure); //初始化串口3 USART_ITConfig(USART3, USART_IT_RXNE, ENABLE);//开启串口接受中断 USART_Cmd(USART3, ENABLE); //使能串口3 } /** *********************************************************** * @brief 对数据进行异或运算 * @param data, 存储数组的首地址 * @param len, 要计算的元素的个数 * @return 异或运算结果 *********************************************************** */ uint8_t CalXorSum(const uint8_t *data, uint32_t len) { uint8_t xorSum = 0; for (uint32_t i = 0; i < len; i++) { xorSum ^= data[i]; } return xorSum; } /** *********************************************************************** 包格式：帧头0 帧头1 数据长度 功能字 指令 异或校验数据 0x55 0xAA 0x02 0x01 0x01 0xFD *********************************************************************** */ void USART3_IRQHandler(void) //串口2中断服务程序 { uint8_t Res; static uint8_t RxState = 0; //当前状态机状态 static uint8_t pRxPacket = 0; //当前接收数据位置 if(USART_GetITStatus(USART3, USART_IT_RXNE) != RESET) //接收中断(接收到的数据必须是0x0d 0x0a结尾) { Res =USART_ReceiveData(USART3); //读取接收到的数据 switch (RxState) { case 0: if (Res == 0x55) { Usart3_RxPacket[pRxPacket] = Res; //将数据存入数组 pRxPacket++; RxState = 1; } else { pRxPacket = 0; RxState = 0; } break; case 1: if (Res == 0xAA) { Usart3_RxPacket[pRxPacket] = Res; //将数据存入数组 pRxPacket++; RxState = 2; } else { pRxPacket = 0; RxState = 0; } break; case 2: Usart3_RxPacket[pRxPacket] = Res; //将数据存入数组 pRxPacket++; if(pRxPacket >= 6) { if ((uint8_t)CalXorSum(Usart3_RxPacket, 5) != (uint8_t)Usart3_RxPacket[5]) { pRxPacket = 0; RxState = 0; } else { RxState = 0; pRxPacket = 0; Usart3_seshig = 66; Usart3_RxFlag = 1; //接收数据包标志位置1，成功接收一个数据包 } } break; default: break; } USART_ClearITPendingBit(USART3, USART_IT_RXNE); //清除标志位 } } 这里void USART3_IRQHandler(void) 函数是干嘛用的，含义是什么？