MATLAB串口开关问题

xiannvjiejie

先描述下问题现象：
        正常打开关闭一次串口后，再次打开串口提示：
       打开失败: Cannot connect to the COM31port. Possible reasons are another application is connected to the port or the port does not exist. 出错 MSerialV1>pbOpenAndClose_Callback(line 122)    fopen(s);

3 @4 p( u7 r, ?. K确认该串口没有在其它程序中使用！

以下是程序代码
, x" y. |, h6 u! ^& Y
7 ^/ ]! |1 k) E1 ^, ^. j/ x8 Bset(handles.pmComPort,'String',seriallist);
! m+ N' f2 q3 B. L; R# xindexCom = get(handles.pmComPort,'Value');
strCom = get(handles.pmComPort,'String');
if indexCom > 1
; h. B) H: O7 F; l, p: @/ g. o    comPort = strCom(indexCom);
else
/ B8 p0 g6 N+ D0 j/ c( c    comPort = strCom;   
) H" [; r. }8 u1 l' @6 n& W& Rend
3 T, `5 p- [# A) ^: v% ~s = serial(comPort);
if handles.pbOpenAndClose.String == "打开"
' [) ~6 @4 ?0 e' K7 i. @    handles.pbOpenAndClose.String = "关闭";
+ y: V  ^9 o0 u% W6 m4 g1 q6 I    handles.pbOpenAndClose.BackgroundColor = 'g';
7 z* @8 @2 B5 o+ D2 z+ N    fopen(s);   
else
  G' y% K% w: _9 U    handles.pbOpenAndClose.String = "打开";
+ Y0 y9 U6 m/ ?* F9 n    handles.pbOpenAndClose.BackgroundColor = 'r';
    fclose(s);
    delete(s);
: A( ]4 u- ?2 G- ~. E    clear s;
end

finishedabc

试试过程中用指令能否正常退出串口，关闭串口