STM32F103串口DMA传输问题

liudingming · 发表于 2016-7-25 09:41:50

请教各位大侠一个问题：
      我现在使用STM32F103的串口2，DMA通道6进行接收固定长度的数据帧，帧长度为13个，但是每次接收的数据都有错位。例如，我通过上位机固定200ms发送一帧数据：为01 02 03 04 05 06 07 08 09 0a 0b 0c 0d，但是软件仿真的时候看DMA接收缓存里面的数据就不对了，接收到的数据有错位的现象，实际收到的为 06 07 08 09 0a 0b 0c 0d 01 02 03 04 05，数据信息还是发送的信息，就是顺序乱了，整了两天了，还是没解决，请教各位大侠是什么原因，如下是我的DMA相关代码：
void Uart2_Init(void)
{
GPIO_InitTypeDef GPIO_InitStructure;
USART_InitTypeDef USART_InitStructure;
DMA_InitTypeDef DMA_InitStructure;
/* Configure USART2 Tx  as alternate function push-pull */
    GPIO_InitStructure.GPIO_Pin = RS485_1_TX_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_AF_PP;
    GPIO_InitStructure.GPIO_Speed = GPIO_Speed_10MHz;
    GPIO_Init(RS485_1_PORT, &GPIO_InitStructure);
    /* Configure USART2 Rx as input floating */
    GPIO_InitStructure.GPIO_Pin = RS485_1_RX_PIN;
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN_FLOATING;
    GPIO_Init(RS485_1_PORT, &GPIO_InitStructure);
    GPIO_InitStructure.GPIO_Pin = RS485_1_EN_PIN;  // 控制485的收发
    GPIO_InitStructure.GPIO_Mode = GPIO_Mode_Out_PP;//推挽输出模式
    GPIO_Init(RS485_1_PORT, &GPIO_InitStructure);
    USART_InitStructure.USART_BaudRate          = RS485_1_COM_BAUD;
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(USART2, &USART_InitStructure);
USART_ITConfig(USART2, USART_IT_RXNE, DISABLE);
DMA_Cmd(DMA1_Channel6, DISABLE);
    DMA_DeInit(DMA1_Channel6);
DMA_InitStructure.DMA_PeripheralBaseAddr = (u32)(&USART2->DR);// 设置串口发送数据寄存器
DMA_InitStructure.DMA_MemoryBaseAddr = (u32)Rs485RxBuf1;
DMA_InitStructure.DMA_DIR = DMA_DIR_PeripheralSRC;
DMA_InitStructure.DMA_BufferSize = RF_DATA_PACKLEN;
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_Circular;       // 循环传输模式
DMA_InitStructure.DMA_Priority = DMA_Priority_VeryHigh;
DMA_InitStructure.DMA_M2M = DMA_M2M_Disable;  // 关闭内存到内存的DMA模式
DMA_Init(DMA1_Channel6, &DMA_InitStructure);
DMA_ITConfig(DMA1_Channel6, DMA_IT_TC, ENABLE);
USART_DMACmd(USART2, USART_DMAReq_Rx, ENABLE);
DMA_ClearFlag(DMA1_FLAG_GL6);
DMA_Cmd(DMA1_Channel6, ENABLE);
USART_Cmd(USART2, ENABLE);
RS485_1_RX_ENABLE;
}

void DMA1_Channel6_IRQHandler(void)
{
if(DMA_GetITStatus(DMA1_IT_TC6))
{
DMA_ClearITPendingBit(DMA1_IT_GL6);
Write_DataFifo(&Rs485Fifo1, &Rs485RxBuf1);
}
}

仿真的时候实时观测Rs485RxBuf1这个buf，里面的内容就是错位的数据。