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Since an 8-bii: output port can only display values between<br />
and 255, what happens when you try to output a value that is ()<br />
side of this range VVould you expect to see a "portion" of the val<br />
say the eight least-significant bits Try running the program Vi<br />
the value 256. What happens<br />
The Apple displays<br />
ILLEGAL QUANT ITY ERROR IN 20<br />
which indicates that the value was not within the proper range<br />
the function that was requested. The line number for the "err<br />
is provided in the error message. Negative numbers are also "caugh<br />
in this way.<br />
Step 6<br />
Restart the program and enter a value of 90. You should observe<br />
a display of 01011010 on the lamp monitors. Now try and enter a<br />
value of -24. When the error is detected, and the<br />
displayed, does the displayed value change<br />
No. Error conditions are detected prior to any attempted use of<br />
POKE function. How do you think the Apple will handle<br />
numbers Enter a decimal fraction, such as 6.01. What is<br />
The Apple will "strip off" the decimal portion of the number.<br />
may wish to experiment with some other numbers, too.<br />
£tep 7<br />
Can you write a short program that could be used to increment<br />
a value from 0 to 255, displaying each new value on the LEDs<br />
Write your program in the space below, and test it. What do you<br />
observe Can you make the program loop back on itself so that the<br />
incrementing counting is displayed again and again
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