如何制作脚踏开关 (四个按钮)

利用RS232的DTR(4脚,输出)、DSR(6脚,输入)和CTS(8脚,输入)

注：这里还可以用RTS(7脚)来代替DTR，而作为输入的还可以用DCD(1脚,输入)和Ring(9脚,输入)

下面的例子运行后，用一导线短接4脚和1脚、4脚和6脚、4脚和8脚、4脚和9脚。
VB脚本：


Option Explicit




Private Sub Form_Load()


MSComm1.PortOpen = True


MSComm1.DTREnable = True


End Sub




Private Sub MSComm1_OnComm()


Select Case MSComm1.CommEvent


Case comEvCD ' Change in the CD line.


Debug.Print "CD"


Case comEvCTS ' Change in the CTS line.


Debug.Print "CTS"


Case comEvDSR ' Change in the DSR line.


Debug.Print "DSR"


Case comEvRing ' Change in the Ring Indicator.


Debug.Print "Ring"


End Select


End Sub



C++脚本:(用的victor 控件)

AnsiString __fastcall Victor_CommDevice::CommDeviceCommNotify(int SBtn, bool Test)
{
//动态结构体赋值
stcom->CTS = CurCommDevice->CTS;
stcom->DCD = CurCommDevice->DCD;
stcom->DSR = CurCommDevice->DSR;
stcom->Ring = CurCommDevice->Ring;
if ((stcom->CTS || stcom->DCD || stcom->DSR || stcom->Ring) && !down)
{ //每次按下只处理一次事件
down = true;
try
{
if (SBtn == 1)
{
ComFlag = "CTS+DCD+DSR+RLSD";
Process();
}
else if (SBtn > 1)
{
if (stcom->CTS)
{
ComFlag = "CTS";
CTS_Process();
}
if (stcom->DCD)
{
ComFlag = "DCD";
DCD_Process();
}
if (stcom->DSR)
{
ComFlag = "DSR";
DSR_Process();
}
if (stcom->Ring)
{
ComFlag = "Ring";
RLSD_Process();
}
if(Test)
{
return ComFlag;
}
}
}
catch (Exception& e)
{
PMSGDLG->ShowErrorMsg("无法指定的重载函数! 错误原因： " + e.Message);
if(Test)
{
return "";
}
Abort();
}
}
else if (!stcom->CTS && !stcom->DCD && !stcom->DSR && !stcom->Ring)
{ //弹开或者其它自动还原数据
down = false;
if(Test)
{
return "";
}
}
}