Create the fullAdder function that implements a full adder (that is made up of t

Question

Create the fullAdder function that implements a full adder (that is made up of two half adders). Of course, you will also need to implement the program in the template to test appropriately. Make sure to use bitwise operators in your implementation of the full adder! A template is provided that will be added to to make a full adder program:

Copyable Code:

import RPi.GPIO as GPIO # bring in GPIO functionality

from random import randint # to generate random integers

# function that defines the GPIO pins for the nine output LEDs

def setGPIO():

# define the pins (change these if they are different)

gpio = [17, 18, 27, 22, 26, 12, 16, 20, 21]

# set them up as output pins

GPIO.setup(gpio, GPIO.OUT)

return gpio

# function that randomly generates an 8-bit binary number

def setNum():

# create an empty list to represent the bits

num = []

# generate eight random bits

for i in range(0, 8):

# append a random bit (0 or 1) to the end of the list

num.append(randint(0, 1))

return num

# function that displays the sum (by turning on the appropriate LEDs)

def display():

for i in range(len(sum)):

# if the i-th bit is 1, then turn the i-th LED on

if (sum[i] == 1):

GPIO.output(gpio[i], GPIO.HIGH)

# otherwise, turn it off

else:

GPIO.output(gpio[i], GPIO.LOW)

# function that implements a full adder using two half adders

# inputs are Cin, A, and B; outputs are S and Cout

# this is the function that you need to implement

def fullAdder(Cin, A, B):

###########################

# write your code here!!!!!

###########################

return S, Cout # yes, we can return more than one value!

# controls the addition of each 8-bit number to produce a sum

def calculate(num1, num2):

Cout = 0 # the initial Cout is 0

sum = [] # initialize the sum

n = len(num1) - 1 # the position of the right-most bit of num1

# step through each bit, from right-to-left

while (n >= 0):

# isolate A and B (the current bits of num1 and num2)

A = num1[n]

B = num2[n]

# set the Cin (as the previous half adder's Cout)

Cin = Cout

# call the fullAdder function that takes Cin, A, and B...

# ...and returns S and Cout

S, Cout = fullAdder(Cin, A, B)

# insert the sum bit, S, at the beginning (index 0) of sum

sum.insert(0, S)

# go to the next bit position (to the left)

n -= 1

# insert the final carry out at the beginning of the sum

sum.insert(0, Cout)

return sum

# use the Broadcom pin scheme

GPIO.setmode(GPIO.BCM)

# setup the GPIO pins

gpio = setGPIO()

# get a random num1 and display it to the console

num1 = setNum()

print " ", num1

# get a random num2 and display it to the console

num2 = setNum()

print "+ ", num2

# calculate the sum of num1 + num2 and display it to the console

sum = calculate(num1, num2)

print "= ", sum

# turn on the appropriate LEDs to "display" the sum

display()

# wait for user input before cleaning up and resetting the GPIO pins

raw_input("Press ENTER to terminate")

GPIO.cleanup()

import RPi.GPIO as GPIO from random import randint # bring in GPIO functionality # to generate random integers # function that defines the GPIO pins for the nine output LEDs def setGPIO ): # define the pins (change these if they are different) gp10= [17, 18, 27, 22, 26, 12, 16, 20, 21] # set them up as output pins GPIO.setup (gpio, GPIO. OUT) return gpio # function that randomly generates an 8-bit binary number def setNum # create an empty list to represent the bits num - # generate eight random bits for i in range (0, 8) # append a random bit (0 or 1) to the end of the list num.append (randint (0, 1)) return num # function that displays the sum (by turning on the appropriate LEDs) def display): for i in range (len (sum)) # if the i-th bit 13 1, then turn the i-th LED on if (sum[i]1): GPIO.output (gpio[i],GPIO.HIGH) otherwise, turn it off else: GPIO.output (gpio[i], GPIO.LOW) # function that implements a full adder using tw half adders # inputs are Cin, A, and B; outputs are S and Cout # this is the function that you need to implement def fullAdder (Cin, A, B) # write your code here! !! !!

Explanation / Answer

import RPi.GPIO as GPIO     # bring in GPIO functionality
from random import randint # allows us to generate random integers

# function that defines the GPIO pins for the nine output LEDs
def setGPIO():
    # define the pins
    gpio = [17, 18, 27, 22, 26, 12, 16, 20, 21]
    # set them up as output pins
    for i in gpio:
        GPIO.setup(i, GPIO.OUT)
    return gpio

# function that randomly generates an 8-bit binary number
def setNum():
    # create an empty list to represent the bits
    num = []
    # generate eight random bits
    for i in range(0, 8):
        # append a random bit (0 or 1) to the end of the list
        num.append(randint(0, 1))
    return num

# function that displays the sum (by turning on the appropriate LEDs)
def display():
    for i in range(len(sum)):
        # turns i-th LED on if i-th bit is 1
        if (sum[i] == 1):
            GPIO.output(gpio[i], GPIO.HIGH)
        # otherwise, turns it off
        else:
            GPIO.output(gpio[i], GPIO.LOW)

# function that implements a full adder using two half adders
# inputs are Cin, A, and B; outputs are S and Cout
def fullAdder(Cin, A, B):
    # first half adder
    S0 = A ^ B
    C0 = A & B
    # second half adder
    S = Cin ^ S0
    C1 = Cin & S0
    # OR statement
    Cout = C0 | C1
    return S, Cout

# controls addition of each 8-bit number; produces a sum
def calculate(num1, num2):
    Cout = 0 # the initial Cout is 0
    sum = [] # initialize the sum
    n = len(num1) - 1 # the position of the right-most bit of num1
    # step through each bit, from right-to-left
    while (n >= 0):
        # isolate A and B (the current bits of num1 and num2)
        A = num1[n]
        B = num2[n]
        # set the Cin (as the previous half adder's Cout)
        Cin = Cout
        # call the fullAdder function that takes Cin, A, and B...
        # ...and returns S and Cout
        S, Cout = fullAdder(Cin, A, B)
        # insert the sum bit, S, at the beginning (index 0) of sum
        sum.insert(0, S)
        # go to the next bit position (to the left)
        n -= 1
    # insert the final carry out at the beginning of the sum
    sum.insert(0, Cout)
    return sum

# use the Broadcom pin scheme
GPIO.setmode(GPIO.BCM)
# setup the GPIO pins
gpio = setGPIO()
# get a random num1 and display it to the console
num1 = setNum()
print "     ", num1
# get a random num2 and display it to the console
num2 = setNum()
print "+    ", num2
# calculate the sum of num1 + num2 and display it to the console
sum = calculate(num1, num2)
print "= ", sum
# turn on the appropriate LEDs to "display" the sum
display()
# wait for user input before cleaning up and resetting the GPIO pins
raw_input("Press ENTER to terminate")
GPIO.cleanup()

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