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This assignment contains two parts: binary puzzles and a binary counter. In this assignment you will: a) use bitwise and Boolean operators to solve basic logical operations on numbers and b) use finite-state machines to model a binary counter. These logic puzzles will help you better understand how binary fits into the day-to-day mechanics of computing. In other words, this assignment will help you think about how computers actually look at and understand data that they interact with.
By the end of this assignment, you should know:
delay()
It’s hard to talk about numbers at all without talking about operators. You should be familiar with many of them already: +
, -
, *
, etc. They take one or two numbers and operate on them, changing them. We introduce two new groups of operators: bitwise operators and Booleans ones.
Bitwise operators are operators that act directly on the individual bits of a binary number, whereas Boolean operators (also known as logical operators) operate on the “logical values” that the complete number represents: in Arduino, 0
is a logical false
, and anything else is true
(even -1
).
In a sense, these two groups of operators are very closely related: both operate only on two values (Boolean operators treat everything as either true
or false
, and bitwise operators operate on the underlying bits of numbers which can each only be 0
or 1
), and as you’ll see in a bit, they perform very similar operations on these values. Their main difference is their scope: bitwise operations work on each bit individually, whereas Boolean operations work on the numbers as a whole.
c = a & b
), c
has 1
s in the places where both of the corresponding bits in a
and b
are 1
.c = a | b
), c
has 1
s wherever at least one of the corresponding bits in a
and b
is 1
.c = a ^ b
), c
has 1
s wherever one and only one of the corresponding bits in a and b is 1
.c = ~a
), c
is a
with each bit inverted.c = a >> b
), c
is a
, with each bit moved lower b
places.c = a << b
), c
is a
, with each bit moved higher b
places.c = a && b
), c
is 1
if both a
and b
are non-zero.c = a || b
), c
is 1
if either a
and b
are non-zero.c = !a
), c
is 1
only if a
is 0
.Not all numbers are the same length. Because of this it is useful to have several different data types that we can choose from for storing differently sized numbers. In this way we don’t waste space storing small numbers in large spaces. The three data types we will use in this lab are characters (char
: 1 byte), integers (int
: 2 bytes), and longs (long
: 4 bytes), each of which store whole numbers.
By default, all of these values are signed
and can store both positive and negative numbers. Their possible values range from and , where n
is the number of bits in the data type. unsigned
numbers range from 0 to . e.g. unsigned char
, unsigned int
and unsigned long
.
Two’s complement is used here to store signed
numbers. If you still have confusions about signed
and unsigned
numbers, please read Introduction to Information Representation guide for detailed explanations.
char
) : Smallest addressable unit that can contain integer data. They are 1 byte (8 bits) in length. Signed characters range between -128
and +127
.int
) : Standard unit to contain integer data. In Arduino C, they contain 2 bytes—16 bits. Signed integers range between -32,768
and 32,767
.long
or long int
) : In Arduino C, they contain 4 bytes or 32 bits. Signed longs range between -2,147,483,648
and 2,147,483,647
.Note: Data types in Java or C have different lengths than in Arduino C.
Open the Arduino sketch called binaryPuzzles
.
Complete the functions shiftRight
and shiftLeft
.
unsigned shiftRight(unsigned num, int n)
: Shift num
to the right n
bits.int shiftLeft(int num, int n)
: Shift num
to the left n
bits.For each function below, use only the bitwise and Boolean operators listed above (i.e., no if-then
tests, comparisons (e.g., ==, !=, >, <, >=, <=), arithmetic operators (e.g., *, +, -, /, %) or for/while
loops are allowed) to write functions that return 1
if the input matches the condition given and 0
otherwise. You may use constant values (e.g., 0
, 1
, 255
, etc.) in your operations. You should be able to solve each in one line.
int hasAOne(int num)
: At least one bit in num
is a one (Binary Representation).
int hasAZero(int num)
: At least one bit in num
is a zero.int leastSigByteHasAOne(int num)
: At least one bit in the least significant byte(the last byte) of num
is a one. (This is NOT just testing whether the lest significant bit is a one.int isNegativeInt(int num)
: the integer num
is negative. int isNegativeLong(long num)
: the long num
is negative. Remember, in Arduino C long
s are 4 bytes (32 bits) in length.int isNegativeChar(char num)
: the char num
is negative. Remember, in Arduino C char
s are 1 byte (8 bits) in length.int negate(int num)
: Return the two’s complement negation of num
. This function should return a number instead of 1
or 0
(true or false). This part has two components: drawing a FSM, and modeling said FSM on your Arduino.
FSM / FSM.ino
The Studio has useful information for this lab. If you were unable to finish the studio last class we recommend you look it over before starting on the assignment.
Here is the drawing of the Studio 1 FSM:
For more information on how to create effective FSMs, watch a short video here.
FSM
directory.FSM.ino
determineNextState()
with a FSM to determine the next state of the machine.
enum
.Here is an Example of an Enum in Arduino C:
enum Direction {
North, // North = 0
East, // East = 1
South, // South = 2
West // West = 3
} direction = North;
switch
statements to switch between your states using cases
if
statements will also be acceptedHere is some pseudocode to demonstrate switch
:
month = 2
switch (month) {
case 1:
print 'January'
break
case 2: // switch to case 2 because month == 2
print 'February'
break // break so other cases won't run
case 3:
print 'March'
break
...
}
checkReverse()
, which reverses the direction of the counter if a key on the keyboard has been pressed.
checkReverse()
should update the state to reflect this. (Be sure the serial monitor has No line ending
selected. Other options, like Newline
will send one or more additional characters and may cause it to reverse multiple times.)**Your Output should look close to this:
We also accept reversing after the next state change, as shown in this older video. Note that it also showed state bits in the incorrect order (least significant bit leftmost rather than rightmost).
shiftRight(int num, int n)
shiftLeft(int num, int n)
hasAOne(int num)
hasAZero(int num)
leastSigHasAOne(int num)
isNegativeInt(int num)
isNegativeLong(long num)
isNegativeChar(char num)
negate(int num)
0 : 000 1 : 001 2 : 010 3 : 011 4 : 100 --Reverse-- 3 : 011 2 : 010 1 : 001 --Reverse-- 2 : 010 3 : 011 --Reverse-- 2 : 010 1 : 001 0 : 000 7 : 111 6 : 110 5 : 101 --Reverse-- 6 : 110 7 : 111 0 : 000 --Reverse-- 7 : 111 6 : 110 5 : 101 4 : 100
Generated at 2023-04-12 18:28:04 +0000.
Page written by Sean Schaffer, Claire Heuckeroth, Ben Stolovitz and Shuya Ma.