                   CHECKERBOARD 

This pattern shows all the visible pixels in an
alternating white and black grid array. 

You can toggle the pattern with the #GR#G trigger, or
turn on auto-toggle each frame with the #GA#G button.

When auto-toggle is set, you should see it
alternating rapidly. On some setups, the pattern
doesn't change at all. This means that the signal
is being treated as 480i/576i and odd or even 
frames are being discarded completely.

A frame counter can be displayed on screen by 
pressing the #GX#G button.
