

                        Parallel Port Debug Tool  V1.0 

                         Copyright 1997 Craig Peacock


Distribution
_____________________________________________________________________________

    This program can be freely distributed provided that this file is
    distributed with the program. No modifications can be made to the
    software.


Disclaimer
_____________________________________________________________________________

    The author can not be liable for damages relating from the use of this
    program or accompanying material. This includes losses relating to
    hardware, software, data or otherwise.

    ***  Use it at your own risk.  ***



General Description
_____________________________________________________________________________

    The parallel port debug tool is a handy utility when debugging devices
    connected to the parallel port. It gives a visual display of the status
    of the three software registers used by the Standard Parallel Port.
    
Ķ
 Base Address     278  Hex     632  Decimal        LPT 1 [ ]  LPT 2 [ ]     
Ķ

    The parallel port base address can be entered in one of two boxes. If
    you wish to enter it as a Hexadecimal number then it would be placed in
    the box labeled Hex, otherwise if it is in decimal form it can be entered
    in the box labeled Decimal.

    There is another option by selecting either LPT 1 Or LPT 2. As stated in
    the authors text found at "http://www.senet.com.au/~cpeacock/parallel.htm"
    BIOS will search for the first port at 3BCh. If a parallel port is found
    there, it will be labeled LPT1, then BIOS will search for the next port,
    when found it will be labeled with the next unused label, thus LPT 1 may
    not be at 378h but rather at 3BCh.

    The Parallel Port Debug Tool will assume that LPT 1 is at base address
    378h or 888 dec and that LPT 2 is at 278h or 632 dec.

    Please Note : The Parallel Port Debug Tool is not very selective about
    which addresses it allows and which addresses it doesn't. Therefore
    entering certain addresses and then performing alterations to their
    registers can crash the computer or result in Data Loss.

    *** Use with Caution. ***


Ķ
 Printer Port     Pin 2  Pin 3  Pin 4  Pin 5  Pin 6  Pin 7  Pin 8  Pin 9    
 Bit Number         0      1      2      3      4      5      6      7      
 Status            [ ]    [ ]    [ ]    [ ]    [ ]    [ ]    [ ]    [ ]     
Ķ

    The next window you will confront is the status of the data port. This
    register has read and write capabilities. If your port is not
    bi-directional you should see the status of the last byte written to this
    port.

    To write to the port you have two choices. You can use the mouse to turn
    each bit on and off. Simply click in side of the [ ]. Another method is
    to use the function keys. F1 toggles Bit 0, F2 toggles Bit 1, . . . .
    & F8 toggles Bit 7.

                     
                      Base + 1   Status Port  (Input)  
                                                       
                      Bit 7 [ ]  Busy        (Pin 11)  
                      Bit 6 [ ]  ACK         (Pin 10)  
                      Bit 5 [ ]  Paper Out   (Pin 12)  
                      Bit 4 [ ]  Select In   (Pin 13)  
                      Bit 3 [ ]  Error       (Pin 15)  
                      Bit 2 [ ]  IRQ (NOT)             
                      Bit 1 [ ]  Reserved              
                      Bit 0 [ ]  Reserved              
                     

    The above window shows the status of the Status Port. The Status port
    is read only, thus you cannot write to this port using this debug tool.
                     
                 Ķ
                   Base + 2   Control Port (Open Collector) 
                                                            
                   Bit 7 [ ]   Reserved                     
                   Bit 6 [ ]   Reserved                     
                   Bit 5 [ ]   Enable Bidirectional Port    
                   Bit 4 [ ]   Enable IRQ via ACK (Pin 10)  
                   Bit 3 [ ]   Select Printer     (Pin 17)  
                   Bit 2 [ ]   Initialize Printer (Pin 16)  
                   Bit 1 [ ]   Auto Linefeed      (Pin 14)  
                   Bit 0 [ ]   Strobe             (Pin 1)   
                 ͼ

    The above window represents the Control Port. This port/register is
    read and write capable. You can use the mouse to turn on and off the
    individual bits and watch the status of the inputs at the same time.
    
    To exit the program at any time, press ESC. 
                                                 
_____________________________________________________________________________

                This Document is Copyright 1997 Craig Peacock
             
        The author can be contacted via Email - cpeacock@senet.com.au

          For more information - http://www.senet.com.au/~cpeacock

