串口取电问题

只看该作者 · 2007-11-7 08:56

我量了一下,串口的,4脚和7脚,对地都是-10V,,,管子都不通,如何会得到5V,想不通.....
各位赐教了....................

2万 · 2007-11-7 10:57

串口4、7脚可以通过PC程序控制输出得到+10V左右电压。

2万 · 2007-11-7 11:02

int CVICALLBACK DTR_CHECKBOX (int panel, int control, int event,
        void *callbackData, int eventData1, int eventData2)
{
    int val;
    int openmode;
    switch (event)
    {
        case EVENT_COMMIT:
            GetCtrlVal (panelHandle, PANEL_COMMCTRLSEL, &openmode);
            if (CommPort) {
              GetCtrlVal (panelHandle, PANEL_CHECKBOX_1, &val);
              if (val == 0)
              {
                  if (openmode == 0)
                  {
                      ComSetEscape (CommPort, CLRDTR);
                  }
                  else
                  {
                    HotComm_SetEscape (CommPort, CLRDTR);
                    SetCtrlVal (panelHandle, PANEL_RILED, HotComm_GetRINGPin (CommPort));
                  }
              }
              else
              {
                  if (openmode == 0)
                  {
                      ComSetEscape (CommPort, SETDTR);
                  }
                  else
                  {
                    HotComm_SetEscape (CommPort, SETDTR);
                    SetCtrlVal (panelHandle, PANEL_RILED, HotComm_GetRINGPin (CommPort));
                  }
              }
              SetCtrlVal (panelHandle, PANEL_DTRLED, val);
              SetCtrlVal (panelHandle, PANEL_COMMERROR, "");
            }
            else {
              SetCtrlVal (panelHandle, PANEL_DTRLED, 0);
              SetCtrlVal (panelHandle, PANEL_CHECKBOX_1, 0);
            }
            break;
    }
    return 0;
}

int CVICALLBACK RTS_CHECKBOX (int panel, int control, int event,
        void *callbackData, int eventData1, int eventData2)
{
    int val;
    int openmode;
    switch (event)
    {
        case EVENT_COMMIT:
            GetCtrlVal (panelHandle, PANEL_COMMCTRLSEL, &openmode);
            if (CommPort) {
              GetCtrlVal (panelHandle, PANEL_CHECKBOX_2, &val);
              if (val == 0)
              {
                  if (openmode == 0)
                  {
                      ComSetEscape (CommPort, CLRRTS);
                  }
                  else
                  {
                    HotComm_SetEscape (CommPort, CLRRTS);
                  }
              }
              else
              {
                  if (openmode == 0)
                  {
                      ComSetEscape (CommPort, SETRTS);
                  }
                  else
                  {
                    HotComm_SetEscape (CommPort, SETRTS);
                  }
              }
              SetCtrlVal (panelHandle, PANEL_RTSLED, val);
            }
            else {
              SetCtrlVal (panelHandle, PANEL_RTSLED, 0);
              SetCtrlVal (panelHandle, PANEL_CHECKBOX_2, 0);
            }
            break;
    }
    return 0;
}