analog line clipping

Zonn said:

"You set the clipping levels to clip just outside the screen. As a vector is
drawn off the edge of the screen it hits the clip edge and moves no farther.
Moving it to 0,0 at this point would cause a line to be drawn to the 0,0."

My idea was to use the "watchdog" hardware on the input of the DACs, which
return the DACs to mid-point if there is no vector activity, to drive any
clipped line to the center of the screen if any of the four boundary comparitors
would fire while a line was being drawn. The fact that the line was clipped
is latched until the "set initial DAC value" signal is asserted again, signaling
the start of the next line draw.

The one thing I forgot to say was that the beam is blanked as soon as clipping
occurs.

The one thing I wonder, though, is if the deflection is fast enough to get from
the center back to the screen edge when the line comes back into range.
Received on Tue Aug 19 16:43:03 1997