在pb中用Api函数与多个串口通讯

Fancy_Free 2005-04-12 02:55:53

现在可以与一个串口通讯，要实现同时与多个串口通讯，即同时打开，同时发送和同时接收怎么写，求助！

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hwh88888 2005-07-15

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首先定义外部函数：
Function Boolean CloseHandle(ulong hObject ) Library "kernel32.dll"

在窗口中定义如下函数
FUNCTION boolean ReadFile(ulong fhand, &
ref string lpbuffer, &
ulong numbyte, &
ref ulong bytesread, &
ulong lpover) LIBRARY "kernel32.dll"

FUNCTION ulong CreateFileA(ref string fname, &
ulong f_access, &
ulong f_share, &
ulong f_sec, &
ulong f_create, &
ulong f_flag, &
ulong f_attrib) LIBRARY "kernel32.dll"

Function Boolean WriteFile(uLong handle,&
ref string lpbuffer, &
ulong numbytes, &
ref ulong bytesread, &
ulong lpOverLaped) Library "Kernel32.dll"

Function Boolean GetCommProperties(ulong hFile,&
ref COMMPROP lpCommProp ) Library "Kernel32.dll"

Function Boolean BuildCommDCBA(ref string lpDef,&
ref DCB lpDCB ) Library "Kernel32.dll"

Function Boolean SetCommState(ulong hCommDev,&
ref DCB lpdcb ) Library "Kernel32.dll"

Function Boolean GetCommState(ulong hCommDev,&
ref DCB lpdcb ) Library "Kernel32.dll"

Function ulong GetLastError() Library "Kernel32.dll"

Function Boolean SetCommTimeouts(ulong hCommDev,&
ref COMMTIMEOUTS lpctmo ) Library "Kernel32.dll"

Function Boolean PurgeComm(ulong hCommDev, &
ulong fdwAction ) Library "Kernel32.dll"
实例变量定义：
ulong iu_file
string is_buffer//数据缓冲
string is_valid_num = "123" //有效数据

第二是初始设置
string ls_com,ls_commset
dcb lst_dcb

ls_com = "COM1"
//ib_reading = true

//打开串口
iu_file = CreateFileA(ls_com,3221225472,0,0,3,128,0)
if (iu_file < 0) then
messagebox("错误","无法打开" + ls_com + " #" + string(getlasterror (
)),StopSign!)
end if

//初始化DCB
ls_commset = "4800,N,8,1"
if (Not BuildCommDcbA ( ls_commset, lst_dcb )) then
messagebox("错误","无法创建DCB" + " #" + string(getlasterror ( )),StopSign!)
end if

//设置串口
if (Not setcommstate ( iu_file, lst_dcb )) then
messagebox("错误","无法设置串口"+ ls_com + " #" + string(getlasterror (
)),StopSign!)
end if

//设置超时
commtimeouts lst_to
lst_to.readintervaltimeout = 4294967295 //MAXDWORD
//lst_to.readtotaltimeoutconstant = 60000
//lst_to.readtotaltimeoutmultiplier = 10
SetCommTimeouts(iu_file, lst_to)

第三步：读或写（例子中的是读，写可用writefile）
ulong lu_bytesread, lu_numbytes
string ls_buff
ulong lstr_locstruct //注意！这是ULONG 而不是STRUCT

ls_buff = space(100)
setnull(lstr_locstruct)
lu_numbytes = 100

if (not readfile ( iu_file, ls_buff, lu_numbytes, &
lu_bytesread, lstr_locstruct)) then
messagebox("错误","无法读取 #" + string(getlasterror ( )),StopSign!)
timer(0)
else
if( lu_bytesread > 0) then
is_buffer += trim(ls_buff)
mle_1.text += trim(ls_buff)
//处理数据
this.wf_is_valid_receieve ( ) //检验函数
end if
end if

第四步：完成后释放端口
closehandle ( iu_file )

其中有几个结构,如不知道可以查查其他的文档

hwh88888 2005-07-15