- INPUT/OUTPUT 4x8 MODULE -

                                       

This Component is a very simple Input/Output module for the PC parallel port. The schematics is simple because the parallel port is already good for I/O because it have 5 pins for input & 12 for output. The project that you can see here is only 4x8 because the module is for the Stereo MP3 project.
Here is a list of components that you need :

       - N° 4 Resistor 10K Ohm
       - N° 1 ULN2803A Module
       - N° 1 Base with holes 
       - N° 4 Light Emitter Diode
       - N° 4 Relays of 6 Volts
       - N° 4 "Socket" for the external connections

                                      

The others 4 output port are unused, you can drive also it if you need it.

This is the electric schematics :

                      

For the output leds, you must connect it to the +5 volts and with the corrects pins like the pictures below :

                            

The Scheme of ULN2803A is this :

         

                                 
                                                     - I/O CONTROLS -

Parallel Pins :

    - N° 8 Pins of OUTPUT at the DATA Address
    - N° 4 Pin of OUTPUT at the CONTROL Address (3 is inverted)
    - N° 5 Pin of INPUT at the STATUS Address (1 inverted)
    - N° 8 Pin of GROUND

   


                                          DATA PORT          
          +----+----+----+----+----+----+----+----+
     | D7 | D6 | D5 | D4 | D3 | D2 | D1 | D0 | Byte DATA Port    
          +----+----+----+----+----+----+----+----+
     |  9 |  8 |  7 |  6 |  5 |  4 |  3 |  2 | Parallel Pins   
          +----+----+----+----+----+----+----+----+


                                        CONTROL PORT          
          +----+----+----+----+----+----+----+----+
     |    |    |    |    | C3 | C2 | C1 | C0 | Byte CONTROL Port    
          +----+----+----+----+----+----+----+----+
     |    |    |    |    | 17 | 16 | 14 |  1 | Parallel Pins   
          +----+----+----+----+----+----+----+----+


                                         STATUS PORT          
          +----+----+----+----+----+----+----+----+
     | S7 | S6 | S5 | S4 | S3 |    |    |    | Byte STATUS Port    
          +----+----+----+----+----+----+----+----+
     | 11 | 10 | 12 | 13 | 15 |    |    |    | Parallel Pins   
          +----+----+----+----+----+----+----+----+

NOTA : The Black Pins is an inverted logics

This is the TURBO PASCAL Code of driving the module :

Program I-O;
uses CRT,DOS;
const  DATA         = $378;
            STATUS     = DATA + 1;
            CONTROL   = DATA + 1;
var      PIPPO : Byte;

Begin
  Port[DATA]  := PIPPO;     {for the Output at the DATA Address}  
  PIPPO := Port[STATUS];  {For The Input at the STATUS Address} 
End.



                                              LINKS FOR THIS PROJECTS :

  - parallel port info : http://www.doc.ic.au.uk/~ih/doc/par/