Parallel Port Debug
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	   Version:  1.1
          Coded by:  Anders Petersson  Gothenburg,Sweden
 Last changes made:  98-08-11


Send comments and ideas to: e6petson@hem.passagen.se


INTRODUCTION

This program should be used for examining and debugging parallel ports
and devices which uses the parallel port. So far it just handles standard
mode (printer mode), but it will probably be extended in the future.

FUNCTION

At startup, the program gets the adresses for LPT1. I do not find it
meaningful to be able to choose printer port, since almost every pc
only has one port. If someone send me a good reason to change it, I will.
The "diodes" and the hex byte shows the register at the current adress,
not whats on the pin. I think that the registers is the most important.
By a simple click in the area around each diode in the data and control
registers, the diode will shift state. (Green=Hi  Blue=Low). The reserved
bytes in the control register won't be affected.
The small window in the upper left corner indicates interrupt requests.
The program automaticly unmasks interrupt, so interrupts can easily be
turned on/off in the control register. In some cases the interrupt
won't work, because the computer needs an End of Interrupt (E.o.I.).
To get rid of this problem (if it should be a problem) the button in the
upper rigth corner labled "E.o.I." will generate a manual e.o.i.
To continue after an interrupt, just click with the mouse anywhere or press
any key.
To choose port, use key F9, F10, F11 or click with the mouse in the right port
info box. If the adress for the chosen port is out of range [200,400] hex, the 
computer will generate a warning. To continue press "Y" or use the mouse.
The last thing to worry about is the EGAVGA.BGI file from Borland, which
must be in the same directory.
