网上流传两个版本的DCB,经过验证有一个有问题

最新推荐文章于 2021-05-24 14:24:42 发布

Pangdaoren

最新推荐文章于 2021-05-24 14:24:42 发布

阅读量1.5k

点赞数

CC 4.0 BY-SA版权

文章标签： integer byte output vb null 测试

本文链接：https://blog.youkuaiyun.com/Pangdaoren/article/details/6649275

本文详细解析了两种DCB结构在串口通信中的应用差异，并针对Windows XP和VB6环境下的具体实现进行了说明。通过对比，文章指出了不同DCB结构在设置波特率、校验方式等参数的有效性及局限性。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

补充:

测试了一下使用左面的结构定义, 使用字符串(baud=1111 parity=E data=8 stop=1)构造DCB只能改变波特率,对校验方式无效

可以用构造后用xDCB.parity=E来解决

右面的结构上面的对校验位有效,但是操作errorchar之类的比较麻烦

----------------------------------------------------------------------------------------------------------------------------------

下面两个DCB结构网上流传很广

其实在XP + VB6环境下右边这个才是准确的

虽然左边这个可以用于设置某些串口参数,但是要进行一些更深入的设置就会出问题,不报错但是设置不起作用

fBitFields:

' The fourteen actual DCB bit-sized data fields within the four bytes of fBitFields can be manipulated by bitwise logical And/Or operations.
' FieldName             Bit #     Description
' -----------------     -----     ------------------------------
' fBinary                 1    1   binary mode, no EOF check
' fParity                 2    1   enable parity checking
' fOutxCtsFlow            3    0   CTS output flow control
' fOutxDsrFlow            4    0   DSR output flow control
' fDtrControl             5    0   DTR flow control type (2 bits)
' fDsrSensitivity         7    0   DSR sensitivity
' fTXContinueOnXoff       8    0   XOFF continues Tx
' fOutX                   9    0   XON/XOFF out flow control
' fInX                   10    0   XON/XOFF in flow control
' fErrorChar             11    1   enable error replacement
' fNull                  12    1   enable null stripping
' fRtsControl            13    0   RTS flow control (2 bits)
' fAbortOnError          15    1   abort reads/writes on error
' fDummy2                16    0   reserved

Type DCB                                        Type DCB
        DCBlength As Long                                DCBlength As Long
        BaudRate As Long                                 BaudRate As Long
        fBinary As Long                                  fBitFields As Long
        fParity As Long                                  wReserved As Integer
        fOutxCtsFlow As Long                             XonLim As Integer
        fOutxDsrFlow As Long                             XoffLim As Integer
        fDtrControl As Long                              ByteSize As Byte
        fDsrSensitivity As Long                          Parity As Byte
        fTXContinueOnXoff As Long                        StopBits As Byte
        fOutX As Long                                    XonChar As Byte
        fInX As Long                                     XoffChar As Byte
        fErrorChar As Long                               ErrorChar As Byte
        fNull As Long                                    EofChar As Byte
        fRtsControl As Long                              EvtChar As Byte
        fAbortOnError As Long                            wReserved1 As Integer 'Reserved; Do Not Use
        fDummy2 As Long                          End Type
        wReserved As Integer
        XonLim As Integer
        XoffLim As Integer
        ByteSize As Byte
        Parity As Byte
        StopBits As Byte
        XonChar As Byte
        XoffChar As Byte
        ErrorChar As Byte
        EofChar As Byte
        EvtChar As Byte
    End Type