Question

TASK: Your task is as follows:

(1) Place SN74LS42N (4 to 10 decoder) on a breadboard;

(2) Connect IC pin 8 to GND and IC pin 16 to +5 V for IC to get powered;

(3) Connect GPIO pins to BCD inputs, as follows:

- connect GPIO pin 12 to IC pin 12 (8’s column),

- connect GPIO pin 16 to IC pin 13 (4’s column),

- connect GPIO pin 20 to IC pin 14 (2’s column) and

- connect GPIO pin 21 to IC pin 15 (1’s column).

(4) Connect GPIO pins to DEC Outputs, as follows:

- connect GPIO pin 25 to IC pin 9,

- connect GPIO pin 8 to IC pin 10,

- connect GPIO pin 7 to IC pin 11,

- connect GPIO pin 26 to IC pin 1,

- connect GPIO pin 19 to IC pin 2,

- connect GPIO pin 13 to IC pin 3,

- connect GPIO pin 6 to IC pin 4,

- connect GPIO pin 5 to IC pin 5,

- connect GPIO pin 11 (SCLK) to IC pin 6 and

- connect GPIO pin 9 (MISO) to IC pin 7.

(5) Connect LEDs and resisters, as follows:

- connect LEDs’ anode (+) to GPIO pins 12, 16, 20 and 21,

- connect LEDs’ cathode (-) to one end of resisters and

- connect the other end of resisters to GND.

(6) Develop a python program to generate a random number using random.randint(0,9) (you need import random) and assign this generated number to DEC, instead of manual input. Convert the random number DEC to a 4-bit binary number and generate the binary signal based on the binary number. Check which decimal outputs D0 – D9 are true/false (on/off).

Answer 1

PROGRAM :

import random
import RPi.GPIO as GPIO # import RPi.GPIO module
GPIO.setmode(GPIO.BCM) # choose BCM or BOARD
GPIO.setup(12, GPIO.OUT) # set a port/pin as an output
GPIO.setup(16, GPIO.OUT) # set a port/pin as an output
GPIO.setup(20, GPIO.OUT) # set a port/pin as an output
GPIO.setup(21, GPIO.OUT) # set a port/pin as an output
GPIO.setup(25, GPIO.IN) # set a port/pin as an Input
GPIO.setup(8, GPIO.IN) # set a port/pin as an Input
GPIO.setup(7, GPIO.IN) # set a port/pin as an Input
GPIO.setup(26, GPIO.IN) # set a port/pin as an Input
GPIO.setup(19, GPIO.IN) # set a port/pin as an Input
GPIO.setup(13, GPIO.IN) # set a port/pin as an Input
GPIO.setup(6, GPIO.IN) # set a port/pin as an Input
GPIO.setup(5, GPIO.IN) # set a port/pin as an Input
GPIO.setup(11, GPIO.IN) # set a port/pin as an Input
GPIO.setup(9, GPIO.IN) # set a port/pin as an Input

  

DEC=random.randint(0,9)

binary= [int(i) for i in bin(DEC)[2:]] # Decimal to binary number conversion

while(len(binary)<4): #adding bit 0 in left to make it 4 bit
  
binary.insert(0,0)

lst=[12,16,20,21]
j=0
for i in binary: #Loading Binary value to DEC input pins
if i==0:
GPIO.output(lst[j], 0) # set port/pin value to 0/GPIO.LOW/False

else:
GPIO.output(lst[j], 1) # set port/pin value to 1/GPIO.HIGH/True

print("The Decimal outputs are (25,8,7,26,19,13,6,5,11,9)respctively ")
print GPIO.input(25)
print GPIO.input(8)
print GPIO.input(7)
print GPIO.input(26)
print GPIO.input(19)
print GPIO.input(13)
print GPIO.input(6)
print GPIO.input(5)
print GPIO.input(11)
print GPIO.input(9)

Note :This programm use gpio pins hence i have imported raspberry pi 's GPIO library as a model but you can import library of your board if yor not using raspberry pi.