9位通讯格式,该如何设置?大哥大姐来帮帮忙好么?

[yyxa82326]

通讯协议是:采用8051异步主从9位通讯协议,起始 D0,D1,D2,D3,D4,D5,D6,D7,D8 停止(说明:起始位1位,D0-D8数据或地址位,D8为数据/地址位的区别位,D8=0表示数据，D8=1表示地址。),请问各位大哥要满足这种通讯协议该如何设置
mscom485.Settings = "4800,m,8,1"
buffer = arr
mscom485.Output = buffer

Select Case m_CmdTmp.CmdType
Case "00", "02", "03", "04", "05"

ReDim arr(2)
arr(0) = Val("&H" & m_CmdTmp.CmdType) '命令号
arr(1) = 0 '传送字节数
arr(2) = Val("&H" & m_CmdTmp.PlantAddr) + arr(0) + arr(1) '校验和

mscom485.Settings = "4800,s,8,1"
buffer = arr
mscom485.Output = buffer

timer485.Enabled = True
m_b485Busy = True '端口忙 ,正在通讯

以上是别人写的程序,但是我不是很懂,为什么mscom485.Settings = "4800,m,8,1"后,还要设置mscom485.Settings = "4800,S,8,1",M(标志位)怎么处理呢?

[yyxa82326]

自己顶起来,我就不相信没人知道回答这个问题!

[yyxa82326]

自己顶一下

[yyxa82326]

没人进来看看吗?

[yyxa82326]

谁来顶一下啊

[guyehanxinlei]

无能为力啊！

[yyxa82326]

不要这样嘛,555,肯定有人知道的!完整的代码是这样的:
ReDim arr(0)
arr(0) = Val("&H" &m_CmdTmp.PlantAddr)

mscom485.Settings = "4800,m,8,1"
buffer = arr
mscom485.Output = buffer

Select Case m_CmdTmp.CmdType
Case "00", "02", "03", "04", "05"

ReDim arr(2)
arr(0) = Val("&H" & m_CmdTmp.CmdType) '命令号
arr(1) = 0 '传送字节数
arr(2) = Val("&H" & m_CmdTmp.PlantAddr) + arr(0) + arr(1) '校验和

mscom485.Settings = "4800,s,8,1"
buffer = arr
mscom485.Output = buffer

timer485.Enabled = True
m_b485Busy = True

[yyxa82326]

555

[akunkeji]

这是典型的Mark/Space校验方式,使用这种校验方式用户可自定义校验位的状态(Mark/Space)即是(1/0),在通讯过程中该校验位可能会根据和下位机的约定进行变换.

如:
MSComm1.Settings="9600,M,8,1" 。其中M为Mark,是把字符校验位置1.
MSComm1.Settings="9600,S,8,1" 。其中S为Space,是把字符校验位置0.