VB host computer and single chip microcomputer

The speed measurement system
collects speed data through the microcontroller, sends it to the PC through the USB port, and generates a curve graph.

MCU program:
//---------------------Serial port initialization----------------------------

void initSerial()
{   
     TMOD=0x20; //Set timer 1 to mode 2
     TH1=0xfd;    
     TL1=0xfd; //Set baud rate to 9600
 SCON = 0x50; //Set serial port working mode
     PCON &= 0x00; //Baud rate does not double
     TR1=1;
     REN=1;
     SM0=0;
     SM1=1;
     EA=1;
     ES=1;
}

//---------------------------Sending program---------------------------------------------
void send_char(void)
//Send 16-bit speed data, low bit first
{
unsigned i=0;

while (i < 6)
{
SBUF =zhuansu_char[i];
while (!TI); // Waiting for special data to be transmitted
TI = 0; // Clear data transmission flag
i++;
}
}
//----------------------Main program--------------------------
void main()
  {         
         uchar receive;
         lcdrs=0;
 init(); //Interrupt initialization
         initSerial(); //Communication initialization
         lcdinit(); //LCD display initialization
 write_project_title();
     while(1)
          {
         
              write_project_data(zhuansu);
              if (RI) // Is there any data coming?
            {
     RI = 0;
     receive = SBUF;
       if (receive == 's') // Start collecting speed?
          {
         send_char(); // Send the collected speed
                        }
               }
      }
}

The VB interface is as follows:
 

The result after debugging is:
 

VB program is as follows:
'Define form-level variables
' Used in display, drawing and other processes
Dim datazhuansu(200) As Single ' Used to store speed sampling value
Dim num As Integer ' Used to store the number of sampling values
​​'-----------------------------------------------
' Speed ​​acquisition
'-----------------------------------------------
Private Sub CmdStart_Click() ' Start acquisition
    Timer1.Enabled = True
End Sub
'-----------------------------------------------
' Stop acquisition
'-----------------------------------------------
Private Sub CmdStop_Click() ' Stop acquisition
          Timer1.Enabled = False
    End Sub
'Serial port initialization
' Add the following code to the Load event of the form to initialize the serial port:
'-----------------------------------------------
' Load the form
'-----------------------------------------------
Private Sub Form_Load()
    MSComm1.CommPort = 1 ' Set the serial port
    MSComm1.InputMode = comInputModeBinary ' Binary input modeMSComm1.RThreshold
    = 1 ' Receive 1 character and trigger the OnComm eventMSComm1.SThreshold
    = 1 ' Send 1 character and trigger the OnComm eventMSComm1.Settings
    = "9600,n,8,2" ' Set the baud rateMSComm1.PortOpen
    = True ' Open the serial portCall
    ScaleSys ' Draw the coordinate systemCmdStop.Enabled
  
    = False
    End Sub
'-----------------------------------------------
' Receive trigger events
'-----------------------------------------------
' Get the speed measurement value and display it
' Each time a command is sent, the following event is triggered and the data string is returnedPrivate
Sub MSComm1_OnComm()
    Dim Inbyte() As Byte ' Temporarily store received dataDim
    buffer As String ' Speed ​​data bufferDim
    datasu2a, datasu2b As String ' Two-byte speed dataDim
    datasu2 As String ' Hexadecimal speed data
       If num > 199 Then 'Judge the number of received data
        Call renew 'Receiving completed
           End If
      'Read the data string returned by the instrument
    Select Case MSComm1.CommEvent
        Case comEvReceive
              Inbyte = MSComm1.Input 'Receive speed data
              For i = LBound(Inbyte) To UBound(Inbyte) 'Put the received data in hexadecimal format into the buffer
            buffer = buffer + Hex(Inbyte(i)) + Chr(32)
        Next i
    End Select
         'Get decimal measurement data
    If Len(Trim(Mid(buffer, 1, 2))) = 1 Then
        datazhuansu(num) = Val("&H" & Mid(buffer, 3,3) & Str("0") & Mid(buffer, 1, 2)) * 0.0625
    Else
        datazhuansu(num) = Val("&H" & Mid(buffer, 3, 3) & Mid(buffer, 1, 2)) * 0.0625
    End If
      'Get hexadecimal measurement dataIf
    Len(Trim(Mid(buffer, 1, 2))) = 1 Then
        datasu2a = Str("0") & Trim(Mid(buffer, 1, 2))
    Else
        datasu2a = Mid(buffer, 1, 2)
    End If
        If Len(Trim(Mid(buffer, 4, 2))) = 1 Then
        datasu2b = Str("0") & Trim(Mid(buffer, 3, 2))
    Else
        datasu2b = Mid(buffer, 4, 2)
    End If
    datasu2 = datasu2a & " " & datasu2b
   
   'Display the measured speed valueIf
   datazhuansu(num) <> 0 Then
        zhuansuText = datasu2
        Call draw ' Call the curve drawing process
          End If
   End Sub
'-----------------------------------------------
' Speed ​​curve drawing
'-----------------------------------------------
' Draw the real-time speed change curve
Private Sub draw()
    Picture1.DrawWidth = 2 ' Set the line width
    Picture1.DrawStyle = vbSolid
       For i = 1 To num - 1
        X1 = (i - 1): Y1 = datazhuansu(i - 1)
        X2 = i: Y2 = datazhuansu(i)
        Picture1.Line (X1, Y1)-(X2, Y2), QBColor(0) ' Draw the speed curve
    Next i
    End Sub
'-----------------------------------------------
' Refresh the drawing area
'-----------------------------------------------
Private Sub renew()
    If num = 0 Then Exit Sub
        zhuansuText.Text = "":
    Picture1.Cls
    Call ScaleSys
    For i = 0 To num - 1
        datazhuansu(i) = 0
    Next i
    num = 0
    Counter = 0
 
End Sub
'-----------------------------------------------
' Send collection flag periodically
'-----------------------------------------------
' Send a read data command string to the instrument every x ms
' Each instrument has an instrument number, and the PC uses the instrument number to identify multiple instruments on the Internet
' The instrument number (i.e. address code) in the program must be consistent with the instrument setting value, otherwise no data can be returned.

Private Sub Timer1_Timer()
    MSComm1.Output = "s" ' Send start flag
    End Sub
'-----------------------------------------------
' Unload the form
'-----------------------------------------------
Private Sub Cmdquit_Click()
    Unload Me ' Unload the form
    End Sub
'-----------------------------------------------
' Establish image coordinate system
'-----------------------------------------------
Sub ScaleSys() ' Coordinate systemPicture1.AutoRedraw
    = True ' Automatically redraw validPicture1.DrawWidth
    = 1 ' Line width 1
    pixelPicture1.ScaleMode = vbPixels ' Pixels as unitPicture1.Scale
    (0, 125)-(200, -50) ' Coordinate systemPicture1.DrawStyle
    = vbDot ' Dot line
    ' Horizontal
    coordinatePicture1.Line (0, 0)-(200, 0), RGB(130, 130, 130)
    Picture1.Line (0, 25)-(200, 25), RGB(130, 130, 130)
    Picture1.Line (0, 50)-(200, 50), RGB(130, 130, 130)
    Picture1.Line (0, 75)-(200, 75), RGB(130, 13 0, 130)
    Picture1.Line (0, 100)-(200, 100), RGB(130, 130, 130)
    Picture1.Line (0, -25)-(200, -25), RGB(130, 130, 130)
    ' Vertical coordinate
    Picture1.Line (25, 125)-(25, -50), RGB(130 , 130, 130)
    Picture1.Line (50, 125)-(50, -50), RGB(130, 130, 130)
    Picture1.Line (75, 125)-(75, -50), RGB(130, 130, 130)
    Picture1.Line (100, 125)-(100, -50), RGB(130, 13 0, 130)
    Picture1.Line (125, 125)-(125, -50), RGB(130, 130, 130)
    Picture1.Line (150, 125)-(150, -50), RGB(130, 130, 130)
    Picture1.Line (175, 125)-(175, -50), RGB(13 0,130, 130)
   
End Sub