Contents of the IOVIEW.DOC file
IOVIEW: A utility to view an IBM-PC's memory mapped I/O ports
Written by J. Ashley Roeckelein. Copyright (c) 1990 Ad Infinitum Software.
This program allows one to view the activity on an IBM-PC (or compatible)
memory mapped I/O ports. The program displays one page (256 bytes) of port
activity at once, and is constantly updated. The full I/O space (256 pages,
or 64K) is accessible via the arrow keys.
To start the program, simply type IOVIEW at the DOS prompt. The arrow
keys will page through the I/O space. To exit the program, press ESC.
Although you won't need this program very often, it can be useful once in
a while. For instance, I wanted to know where the joystick port was, and I
did not have any documentation on the joystick adapter. By using this program,
I was able to determine the port address (201 hex) and the values returned by
the joystick buttons (f0 hex for no button pressed, d0 hex for the left button,
and e0 hex for the right button). Enjoy! (and look for other A.I.S. products!)
This program may be freely distributed as long as: (1) no charge is made
for the program (except for a small disk handling charge not to exceed $15),
and (2) all files remain in their original, unmodified state.