图片与matlab gui之间的UART

Question

我在使用MATLAB GUI将pic微控制器与pc连接时遇到了麻烦 Matlab给了我这个错误＆＃34;警告：在达到终结者之前发生超时＆＃34;

这是mikroc代码：

void main() 
{
    char x,send;
    TRISD = 0x00;
    TRISB = 1;
    while(1)
    {
        if (PORTB.f0==1)
        {
            UART1_Init(9600);
            Delay_ms(100);
            UART_Write('s');
            x = 0;
            while(x==0)
            {
                x = UART1_Read();
                if (x=='y')
                {
                    PORTD.f0=1; Delay_ms(1000); PORTD.f0=0;  
                }
                else if (x=='n')
                { 
                    PORTD.f1 = 1;  
                    Delay_ms(1000);  
                    PORTD.f1 = 0;
                }
            } 
       }
  }

}

这是matlab代码：

function pushno_Callback(hObject, eventdata, handles)

delete(instrfind);
s = serial('COM4');
set(s,'BaudRate',9600,'DataBits', 8, 'Parity', 'none','StopBits', 1, 'FlowControl',   none','Terminator','CR');

s.BytesAvailableFcnCount = 1;
s.BytesAvailableFcnMode = 'byte';
s.BytesAvailableFcn=@mycallback;
handles.pushno=s;
fopen(s);

function mycallback(hObject, event, handles)
s=handles.pushno;
out=fscanf(s);
if (out=='s')
pause(1);
fprintf(s,'y');
end 
fclose(s);
delete(s);
clear s;