Wednesday, December 02, 2009 3:27 AM,

I have gotten about a dozen messages from students about the screen shots.
Some have gotten only screen shot 2, most have gotten only screen shot 1.
Each of the emails seems troubled by the fact that only one of the two has 
been observed.

The reason you are seeing only one screen shot curiously depends on how much 
delay is in the subroutine DELAY and exactly when it is called.  Those who 
call DELAY after every line of the UT checkerboard get almost always screen 
shot 1, although occasionally, if they type the key at exactly the right 
moment, they will get screen shot 2.  Those who call DELAY after every "UT" 
is output will almost always get screen shot 2, unless they happen to type the 
key at exactly the right time.

These results ars due to the fact that most of the time, the LC-3 is executing 
the subroutine DELAY.  

If the subroutine is called at the end of a line, then most of the time the 
key is typed when the checkerboard is displaying the last full line.  
Therefore, screen shot 1.

If the subroutine is called after each UT is typed, then most of the time the 
key is typed when the checkerboard is displaying an incomplete last line.  
Therefore screen shot 2.

The only reason we put the delay in there in the first place was to slow down 
the scrolling of the UT checkerboard long enough for you to see the ten 
characters caused by your typing.  The delay is pretty incidental to the 
learning experience of interrupts.

Bottom line: Don't worry about it.  If you are only getting one of the two 
screen shots, it is probably because of when the LC-3 is processing the DELAY 
subroutine.  If you are doing what the specification asks, you will receive 
full credit for prog5.