串口多字节接收

/* 数据发送格式：
 *   0       1          2             3        4   ...   DataLenth-1  DataLenth
 * HEAD1 - HEAD2 - DataLenth(n+1) - data_1 - data_2 - ... - data_n - CheckSum
 * CheckSum = HEAD1 + HEAD2 + DataLenth + data_1 + data_2 + ... + data_n
 */

#define FRAME_HEADER1 0xFA    // 定义帧头 1
#define FRAME_HEADER2 0xFA    // 定义帧头 2
unsigned char ReceiveDataBuffer[16] = {FRAME_HEADER1, FRAME_HEADER2, 0x00};
unsigned char DataBufferCnt = 0x02;
unsigned char CheckSum = FRAME_HEADER1 + FRAME_HEADER2;
// 串口接收中断程序
void USART_IRQHandler(void)
{
    static unsigned char headBufCnt = 0x00;
    unsigned char buf;

    buf = ReadRegisterReceiveBuffer();    // 读接收寄存器数据到缓冲区

#if (FRAME_HEADER1 != FRAME_HEADER2)    // 检测帧头，两字节帧头不同
    if(FRAME_HEADER1 == buf) { headBufCnt = 0x01;}
    else if(0x00 != headBufCnt)
    {
        headBufCnt = 0x00;
        if(FRAME_HEADER2 == buf)
        {
            DataBufferCnt = 0x02;
            CheckSum = FRAME_HEADER1 + FRAME_HEADER2;
            return;
        }
    }
#else    // 检测帧头，两字节帧头相同
    if(FRAME_HEADER1 == buf) { headBufCnt ++;}
    else if(headBufCnt >= 2)
    {
        headBufCnt = 0x00;
        DataBufferCnt = 0x02;
        CheckSum = FRAME_HEADER1 + FRAME_HEADER2;
    }
    else { headBufCnt = 0x00;}
#endif /* FRAME_HEADER1 != FRAME_HEADER2 */
    
    ReceiveDataBuffer[DataBufferCnt] = buf;
    if((DataBufferCnt-2) < ReceiveDataBuffer[2])
    {
        CheckSum += ReceiveDataBuffer[DataBufferCnt];    // 计算校验和
        DataBufferCnt ++;
    }
    else    // 数据接收完毕
    {
        if(CheckSum == ReceiveDataBuffer[DataBufferCnt])    // 数据校验成功
        {
            // 数据校验完毕且正确
        }
        DataBufferCnt = 0x02;
    }
}