本人想用STM32的DMA和串口1 的ILDE模式接收不定长数据帧，遇到一个奇怪的现象，当串口助手V2.0（正点原子的）手动发送所需要的数据包时，误包率很高，而改为60ms自动发送就几乎没有出现误包的问题，所谓的误包问题要不出现功能码出错，要不帧长度出现错误了。- void Configuration_GPIO()
- {
- GPIO_InitTypeDef GPIO_InitStructure;
- // USART1_TX:PA9
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_9;
- GPIO_InitStructure.GPIO_Speed = GPIO_Speed_50MHz;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
- GPIO_Init(GPIOA, &GPIO_InitStructure);
- // USART1_RX:PA10
- GPIO_InitStructure.GPIO_Pin = GPIO_Pin_10;
- GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
- GPIO_Init(GPIOA, &GPIO_InitStructure);
- }
- #include "Configuration_DMA.h"
- u8 RecBuffer[RecLength] = {0};
- u8 Usart1_Rec_Cnt = 0;
- void Configuration_DMA_USART()
- {
- DMA_InitTypeDef DMA_InitStructure;
-
- /* 该DMA用于USART快速传输一帧数据，单字节时不需要 */
- DMA_DeInit(DMA1_Channel5);
- DMA_InitStructure.DMA_PeripheralBaseAddr = (u32) &USART1->DR;
- DMA_InitStructure.DMA_MemoryBaseAddr = (u32) &RecBuffer;//这是初始化时候配置，可以根据程序运行重新设置。
- DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
- DMA_InitStructure.DMA_BufferSize = RecLength;
- DMA_InitStructure.DMA_PeripheralInc = DMA_PeripheralInc_Disable;
- DMA_InitStructure.DMA_MemoryInc = DMA_MemoryInc_Enable;
- DMA_InitStructure.DMA_PeripheralDataSize = DMA_PeripheralDataSize_Byte;
- DMA_InitStructure.DMA_MemoryDataSize = DMA_MemoryDataSize_Byte;
- DMA_InitStructure.DMA_Mode = DMA_Mode_Normal;
- DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
- DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;
- DMA_Init(DMA1_Channel5, &DMA_InitStructure);
- DMA_Cmd(DMA1_Channel5, ENABLE);
- }
- void Control_NVIC_USART1(FunctionalState NewStatus)
- {
- NVIC_InitTypeDef NVIC_InitStructure;
- // 设置NVIC中断分组4:4位抢占优先级，0位响应优先级
- NVIC_PriorityGroupConfig(NVIC_PriorityGroup_4);
-
- NVIC_InitStructure.NVIC_IRQChannel = USART1_IRQn;
- NVIC_InitStructure.NVIC_IRQChannelCmd = NewStatus;
- NVIC_InitStructure.NVIC_IRQChannelPreemptionPriority = 0;
- NVIC_InitStructure.NVIC_IRQChannelSubPriority = 0;
- NVIC_Init(&NVIC_InitStructure);
- }
- void Configuration_USART(u32 baudrate)
- {
- USART_InitTypeDef USART_InitStructure;
- USART_InitStructure.USART_BaudRate = baudrate;
- USART_InitStructure.USART_WordLength = USART_WordLength_8b;
- USART_InitStructure.USART_StopBits = USART_StopBits_1;
- USART_InitStructure.USART_Parity = USART_Parity_No;
- USART_InitStructure.USART_HardwareFlowControl = USART_HardwareFlowControl_None;
- USART_InitStructure.USART_Mode = USART_Mode_Rx | USART_Mode_Tx;
- USART_Init(USART1, &USART_InitStructure);
- USART_ITConfig(USART1, USART_IT_RXNE, DISABLE); // 不使能接收中断
- USART_ITConfig(USART1, USART_IT_TC, DISABLE); // 不使能发送中断
- USART_ITConfig(USART1, USART_IT_IDLE, ENABLE); // 使能空闲中断
- USART_ClearFlag(USART1, USART_FLAG_TC);
- USART_DMACmd(USART1, USART_DMAReq_Rx, ENABLE);
- USART_Cmd(USART1, ENABLE);
- // 防止首字节丢失
- while(USART_GetFlagStatus(USART1,USART_FLAG_TC) == RESET);
- }
- void USART1_SendByte(uint8_t c)
- {
- USART_SendData(USART1, (uint8_t)c);
- while(USART_GetFlagStatus(USART1,USART_FLAG_TC) == RESET);
- }
- void USART1_SendNByte(u8 *pData,u8 Length)
- {
- while(Length--)
- {
- USART1_SendByte(*pData);
- pData++;
- }
- }
- void USART1_IRQHandler(void)
- {
- u8 i;
- if(USART_GetITStatus(USART1, USART_IT_IDLE) != RESET)
- {
- // 关闭USART1 TX DMA1 所指示的通道
- DMA_Cmd(DMA1_Channel5, DISABLE);
- // 读取数据 注意：这句必须要，否则不能够清除中断标志位。我也不知道为啥！
- USART_ReceiveData(USART1);
- // 算出接本帧数据长度
- Usart1_Rec_Cnt = RecLength - DMA_GetCurrDataCounter(DMA1_Channel5);
- if(Usart1_Rec_Cnt != 8)
- Usart1_Rec_Cnt = 0;
- /*------------------------串口测试段--------------------------------*/
- for(i = 0;i < Usart1_Rec_Cnt;i++)
- RecBuffer1[i] = RecBuffer[i];
- //***********帧数据处理函数************//
- // printf ("The lenght:%d\r\n",Usart1_Rec_Cnt);
- // printf ("The data:\r\n");
- // USART1_SendNByte(RecBuffer, Usart1_Rec_Cnt);
- // printf ("\r\nOver! \r\n");
- //*************************************//
-
- // 清除中断标志
- USART_ClearITPendingBit(USART1, USART_IT_IDLE);
- // DMA通道的DMA缓存的大小
- DMA_SetCurrDataCounter(DMA1_Channel5, RecLength);
- // 使能USART1 TX DMA1 所指示的通道
- DMA_Cmd(DMA1_Channel5, ENABLE);
- }
- }
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