User`s manual

Figure 6: User Interface
When pressed, button 0 triggers the audio system, which announces the
percentage of screen pixels currently used for the corrected image. LEDs 7-1
show the binary representation of this value. Buttons 2 and 3 adjust the volume
of the audio system up or down. The first four digits on the hex display show the
current x acceleration value, the next four show the current y acceleration value,
the next four show the x coordinate of the corner of the quadrilateral selected
by switches 0 and 1, and the last four show the y coordinate of this corner.
If switch 7 is high, we are in manual correction mode, and the accelerometer
readings are ignored. In this mode, we can manually adjust the corner of the
quadrilateral selected by switches 0 and 1 by pressing the up and down buttons
(to adjust the x coordinate) and the left and right buttons (to adjust the y
coordinate). When switch 5 is high, we display a checkerboard on the screen
instead of the NTSC camera input.
7 Testing And Debugging
Testing and debugging Verilog-defined hardware is complicated due to the large
synthesis times. Unlike software, where one can change a single line of code, and
23