help with Matlab and serial communication

Comments

• Publison Posts: 12,366

  2011-03-09 04:35 edited 2011-03-09 04:35

  You have to use the BAUDMODE number for the baud rate on BS2'. Look in the SEROUT section of the Basic Stamp manual or the Help in the Basic Stamp Editor for the table of acceptable BAUDMODE numbers. Be sure and pick the table for the BS2P.
  

  erick_2987 wrote: »

  hi all,
  i am trying to establish a serial communication with my bs2p and matlab. Here is my bs code:
  *************************************************
  ' Variables
  test VAR Word
  
  '**********************
  ' Main Program
  
  test = 6
  
  Main:
  SEROUT 16,2400,[DEC test, CR]
  
  PAUSE 250
  GOTO Main
  
  END
  ***********************************************************
  
  and my matlab code:
  ***************************************************************************************************
  s = serial('COM3','BaudRate',2400,'DataBits',8,'Parity', 'none', 'FlowControl', 'none');
  s.terminator = 'CR';
  s.ReadAsyncMode = 'manual';
  fopen(s)
  
  s_scan = fscanf(s,'%d\n');
  s_get = fgetl(s);
  s_read = fread(s);
  fclose(s);
  ********************************************************************************************************
  
  when i execute the program, the output from the matlab is:
  Warning: A timeout occurred before the read operation completed.
  Warning: A timeout occurred before the read operation completed.
  Warning: The specified amount of data was not returned within the Timeout period.
  
  meanwhile the debug window in bs2 gives me:
• erick_2987 Posts: 11

  2011-03-09 08:40 edited 2011-03-09 08:40

  hi, sorry for the above mistake.I have set the baudrate at 9600 but still unable to get the answer.
• Publison Posts: 12,366

  2011-03-09 11:15 edited 2011-03-09 11:15

  What value did you use for BAUDMODE?
  

  erick_2987 wrote: »

  hi, sorry for the above mistake.I have set the baudrate at 9600 but still unable to get the answer.
• Mike G Posts: 2,702

  2011-03-11 18:14 edited 2011-03-11 18:14

  Stamp code

  ' {$STAMP BS2p}
  ' {$PBASIC 2.5}
  
  #SELECT $STAMP
    #CASE BS2SX, BS2P
      N2400        CON     1021+$8000
    #CASE BS2PX
      N2400        CON     1646+$8000
    #CASE #ELSE
      N2400        CON     396+$8000
  #ENDSELECT
  
  test    VAR      Byte
  test = 6
  
  Main:
    SEROUT 16,N2400,[DEC test, CR]
    PAUSE 250
  GOTO Main
  

  
  MAtLab
  

  function SerialTest()
  
      % Set the port paramenter
      s=serial('COM16', 'BaudRate', 2400, 'Parity', 'none', 'DataBits', 8, 'StopBits', 1);
      s.terminator = 'CR';
      % open the port
      fopen(s);
      
      % display the com port resources
      com = instrfind;
      disp(com);
    
      % Expecting 1 byte
      out=fread(s,1);
      
      % Display the byte
      disp(out);
      
      % Clean up
      fclose(s);
      delete(s);
      clear s;
  end
  

  
  Command Window

     Serial Port Object : Serial-COM16
  
     Communication Settings 
        Port:               COM16
        BaudRate:           2400
        Terminator:         'CR'
  
     Communication State 
        Status:             open
        RecordStatus:       off
  
     Read/Write State  
        TransferStatus:     idle
        BytesAvailable:     0
        ValuesReceived:     0
        ValuesSent:         0
   
      54
  
  >> 
  

  
  The result is 54 or 0x36 which is ASCII for 6.
• erick_2987 Posts: 11

  2011-03-11 18:29 edited 2011-03-11 18:29

  my baudmode is 240
• Mike G Posts: 2,702

  2011-03-11 19:00 edited 2011-03-11 19:00

  my baudmode is 240

  
  Not following you.
  Did you try the code and it didn't work? Make sure you update the COMxx port in MatLab.
  What is 240? 2400 baud?
  
  1021 equals 2400 baud in the BS2p SEROUT command. See basic stamp help.
  

  SEROUT 16, 1021, [DEC test, CR]
  

  
  Open mode

  SEROUT 16, 1021 + $8000, [DEC test, CR]