lesson9.txt

#color 0xffc3e1fe
#coord 305 17
#title The Subframe Lessons
#title 109: NOR Logic

#font 7px
#color 0xfffbfbbb
#coord 37 46
#section 9.1 NOR Gates

A NOR gate outputs ON if neither of its inputs are ON.
You saw how to make a simple subframe NOR gate in the previous lesson.

Let's take a quick break from subframe to review
some principles of digital logic design.

#section 9.2 NOR Logic

NOR gates are universal -- any logic circuit can be constructed
entirely out of NOR gates.

A NOT gate outputs ON only if its input is OFF.
It can be constructed from a NOR gate by leaving
one input OFF.

An OR gate outputs ON if either of its inputs are ON.
It can be constructed by adding a NOT gate after a
NOR gate.

An AND gate outputs ON only if both its inputs are ON.
That is, it outputs ON only if neither input is OFF.

More schematics can be found in the Wikipedia article on NOR logic.

Warning: The NOR gate used in this lesson cannot be rotated.

#font 5px
#color 0xffbefcc4
#coord 410 48
#section Activity #9.1

An XOR gate outputs ON if exactly one,
but not both, of its inputs are ON.

Construct an XOR gate out of NOR gates.
Use the provided NOR gate design.

If you get stuck, you can consult
the Wikipedia schematics.

#answer 150 30

#section Activity #9.2

Make a subframe AND gate using
DRAY NOR gates.

For simplicity, point all your
DRAYs rightwards.

Here's a subframe OR gate,
for reference.

#space 20

#answer 150 10

Bonus: Make a subframe XOR gate.

#answer 150 10