This project is one I have
      wanted to do for years, to be able to send serial micro controller
      data directly to the PC into a terminal program. The heart of
      this board is the Maxim 232 chip, which by use of 1uF capacitors
      will generate double the input voltage to a level of +/- 10v
      to send to the serial port on my laptop. As you may remember,
      micro controllers put out a TTL level signal which is 0 to 5v
      and this must be converted to +/- 10v inverted to put into the
      computer. The board works great, and can be easily tested by
      connecting pins 2 and 3 of the output connector to feed the serial
      data back in and be recieved by the terminal program. As you
      type, it appears on the display as it comes in from the loop
      through.
Click images for a larger more detailed view
 

      

Here
      is the board, with its own 5v regulator, the DB9-F connector
      to connect to the PC, and a 110v/12v dc power supply.


      

Here
      the Cbot is connected to the PC and sending it data! The screen
      is at least 80 charecters wide, depending on the font used, and
      infinitely long. A perfect application is data logging of temperatures,
      lighting conditions and analog data to be imported into the chart
      wizard in Excel for graphing.
 

      

Schematic
      (click to enlarge). many of the data books I consulted confuse
      pins 2 and 3 on the PC for xmit or recieve. I finally took an
      oscilloscope and looked for the data as I pressed the keyboard.

      
 Sample code to
      send text and various types of numbers to the PC screen:

      
 //for LCD
      / Terminal:

      #use rs232(baud=9600, xmit=Pin_B1, bits=8, parity=N,stream=TERMINAL)

      
   int8 n = 255;

         int16 x = 50000;

         float y = 65000.123;  //only 7 digit precision will truncate
      last digit

         float z = 3.14159;

         

         //----------------------------------------------------------------

      
//MAIN PROGRAM:

      
while (true)  
      {

      
   //First flash
      lamp

         

         output_high(Pin_B0);

         delay_ms(250);

         output_low(Pin_B0);

         delay_ms(250);

         

         //Now send messages to Terminal:

         

         delay_ms(1000);

         

         fprintf(TERMINAL,"Hello World");  //text plus integer8
      (Byte)

         fprintf(TERMINAL,"\n\r");              //New line,
      Carrige Return

        

         delay_ms(250);

         

         //Displays: ROBOT BOARD= 255

         fprintf(TERMINAL,"ROBOT BOARD= %u"n);  //text plus
      integer8 (Byte)

         fprintf(TERMINAL,"\n\r");              //New line,
      Carrige Return

        

         delay_ms(250);

         

         //Displays: Value= 50000

         fprintf(TERMINAL,"Value= %Lu"x);  //text plus Integer
      16 (word)

         fprintf(TERMINAL,"\n\r");         //New line, Carrige
      Return

        

         delay_ms(250);

         

         //Displays: floating= 65000.120

         fprintf(TERMINAL,"floating= %8.3f"y);  //text plus
      floating point

         fprintf(TERMINAL,"\n\r");              //New line,
      Carrige Return

        

         delay_ms(250);

         

         //Displays: floating= 65000.12

         fprintf(TERMINAL,"floating= %f"y);  //text plus
      floating point DEFAULT float

         fprintf(TERMINAL,"\n\r");              //New line,
      Carrige Return

        

         delay_ms(250);

         

         //Displays: floating= 3.14159

         fprintf(TERMINAL,"floating= %6.5f"z);  //text plus
      floating point

         fprintf(TERMINAL,"\n\r");              //New line,
      Carrige Return

        

         delay_ms(250);

           }  //elihw

        

      }  //niam
 

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