Digital design fundamentals

System Design Technologies

There are four design technologies:

1. Fixed-Function IC 
2. Full Custom ASIC
3. Semi Custom ASIC
4. PLD Technology

Fixed-Function IC

In this type  the IC is designed for a fixed application. We call it as ASIC(Application Specific Integrated Circuit).

Here the cost of making a single IC  is very much high. Also time to market is high.

Full Custom ASIC

A full custom ASIC is one where mostly all the blocks(logic blocks) are customized. A microprocessor is an example of Full custom ASIC.

Semi Custom ASIC

Here all the logic cells are predesigned and some(possibly all) the mask layers are customized. Using the predesigned cells in the library makes the design easy.

PLD Technology

Programmable logic devices are special ICs that are available in market in standard configurations. They can be configured to create a part customized to a specific application and hence belong to family of ASICS

BMI Calculator using Python Tkinter module

Using Python's Tkinter module, here I have implemented a BMI calculator.

BMI introduction

BMI is a measurement of a person's leanness or corpulence based on their height and weight, and is intended to quantify tissue mass. It is widely used as a general indicator of whether a person has a healthy body weight for their height. Specifically, the value obtained from the calculation of BMI is used to categorize whether a person is underweight, normal weight, overweight, or obese depending on what range the value falls between.

BMI table for adults

This is the World Health Organization's (WHO) recommended body weight based on BMI values for adults. It is used for both men and women, age 18 or older.

Category	BMI range - kg/m2
Severe Thinness	< 16
Moderate Thinness	16 - 17
Mild Thinness	17 - 18.5
Normal	18.5 - 25
Overweight	25 - 30
Obese Class I	30 - 35
Obese Class II	35 - 40
Obese Class III	> 40

Below is the Python program and corresponding output window is shown.

from tkinter import *

def bmi_calci():
    weight = float(weight_input.get())
    height = float(height_input.get())
    res = round((weight/(height*height))*10000, 2)
    bmi_result_label.config(text=f"{res}")

window = Tk()
window.title("BMI Calculator")
window.minsize(width=250, height=150)
window.config(padx=20, pady=20)

weight = Label(text="Weight is")
weight.grid(column=0, row=0)
height = Label(text="Height is")
height.grid(column=0, row=1)
weight_input = Entry(width=12)
weight_input.grid(column=1, row=0)
height_input = Entry(width=12)
height_input.grid(column=1, row=1)

weight_label = Label(text="KG")
weight_label.grid(column=2, row=0)
height_label = Label(text="CM")
height_label.grid(column=2, row=1)

bmi_label = Label(text="Your BMI is ")
bmi_label.grid(column=0, row=2)
bmi_result_label = Label(text="0")
bmi_result_label.grid(column=1, row=2)
bmi_unit_label = Label(text="Kg/m^2")
bmi_unit_label.grid(column=2, row=2)

calculate_button = Button(text="Calculate", command = bmi_calci)
calculate_button.grid(column=1, row=3)



window.mainloop()

Output Window:

Link to Calculate BMI online: BMI Calculator

DCA September 2021: Check number is "UNO" or "NOT UNO"

Following code is to check if a given positive integer input by user is UNO number or NOT UNO

For e.g. if user input is 1234 then here the sum of digits if the given number is 1+2+3+4 = 10 and then again if we sum the digits of resulting number i.e. 10 is 1+0 = 1 hence if this kind of sum of digits of a number is 1 then the number is said UNO else NOT UNO

NOT UNO e.g. 234 here sum of digits is 2+3+4 = 9, this is not equal to 1 hence it is said NOT UNO

Python Program: 

num = int(input()) #takes user input

def check_uno(num):
    sum_d = 0
    k = 0
    while num > 0:
        k = num % 10
        sum_d = sum_d + k
        num = num // 10
    if sum_d == 1 or sum_d == 10:
        print("UNO")
    elif (sum_d > 1 and sum_d < 10):
        print("NOT UNO")
    elif sum_d > 11:
        b = check_uno(sum_d)

check_uno(num)

#Output:

Input = 1234
Output = UNO

Input = 12345
Output = NOT UNO
Input = 345345
Output = NOT UNO

IC555: Astable Multivibrator- LED blinking/Dancing

The 555 Timer IC can be connected either in its Monostable mode thereby producing a precision timer of a fixed time duration, or in its Bistable mode to produce a flip-flop type switching action. But we can also connect the 555 timer IC in an Astable mode to produce a very stable 555 Oscillator circuit for generating highly accurate free running waveforms whose output frequency can be adjusted by means of an externally connected RC tank circuit consisting of just two resistors and a capacitor.

Below video shows implemented circuit in Proteus design suite. You can see the LEDs connected to output pin are blinking continuously. 

In the 555 Oscillator above video, pin 2 and pin 6 are connected together allowing the circuit to re-trigger itself on each and every cycle allowing it to operate as a free running oscillator. During each cycle capacitor, C charges up through both timing resistors, R1 and R2 but discharges itself only through resistor, R2 as the other side of R2 is connected to the discharge terminal, pin 7.

Then the capacitor charges up to 2/3Vcc (the upper comparator limit) which is determined by the 0.693(R1+R2)C combination and discharges itself down to 1/3Vcc (the lower comparator limit) determined by the 0.693(R2*C) combination. This results in an output waveform whose voltage level is approximately equal to Vcc – 1.5V and whose output “ON” and “OFF” time periods are determined by the capacitor and resistors combinations. The individual times required to complete one charge and discharge cycle of the output is therefore given as:

Python: Program for Area of Rectangle, Circle, and Square

 Below is the program which calculates the areas of Rectangle, Circle, and Square. It takes the inputs from user such as length and width for Rectangle, radius for Circle, and side of Square for Square.

Code:

length = int(input("Enter the length of the Rectangle "))

width = int(input("Enter the width of the Rectangle "))

radius = int(input("Enter radius of Circle "))

side = int(input("Enter side of the Square "))

class Area:

    def __init__(self, length, width, radius, side,):

        self.length = length

        self.width = width

        self.radius = radius

        self.side = side

 

    def Rect_area(self):

        rect_area = self.length*self.width

        print(f"Area of the Rectangle = {rect_area} Sq.Units")

    def Cir_area(self):

        cir_area = 3.14*self.radius**2

        print(f"Area of circle = {cir_area} Sq.Units")

   

    def Squ_area(self):

        squ_area = self.side**2

        print(f"Area of Square = {squ_area} Sq.Units") 

 

rectangle = Area(length, width, radius, side)

circle = Area(length, width, radius, side)

square = Area(length, width, radius, side)

rectangle.Rect_area()

circle.Cir_area()

square.Squ_area()

Output:

Enter the length of the Rectangle 5

Enter the width of the Rectangle 6

Enter radius of Circle 4

Enter side of the Square 7

Area of the Rectangle = 30 Sq.Units

Area of circle = 50.24 Sq.Units

Area of Square = 49 Sq.Units

Python: Finding area of rectangle

The program shown below calculates the area of the rectangle for given user inputs of length and width.

#Program:

length = int(input("Enter the length of the Rectangle "))

width = int(input("Enter the width of the Rectangle "))

class Rectangle:

    def __init__(self, length, width):

        self.length = length

        self.width = width

    def area(self):

        rect_area = self.length*self.width

        print("Area of the Rectangle = ", rect_area)

 

area1 = Rectangle(length, width)

area1.area()

Output:

Enter the length of the Rectangle 7

Enter the width of the Rectangle 9

Area of the Rectangle =  63

BJT: RC coupled single stage amplifier

 

Common emitter RC coupled amplifier.

The common emitter RC coupled amplifier is one of the simplest and elementary transistor amplifier that can be made. Don’t expect much boom from this little circuit, the main purpose of this circuit is pre-amplification i.e to make weak signals strong enough for further processing or amplification. If designed properly, this amplifier can provide excellent signal characteristics. The circuit diagram of a single stage common emitter RC coupled amplifier using transistor is shown below.

Capacitor C1 is the input DC decoupling capacitor which blocks any DC component if present in the input signal from reaching the Q1 base. If any external DC voltage reaches the base of Q1, it will alter the biasing conditions and affects the performance of the amplifier.

R1 and R4 are the biasing resistors. This network provides the transistor Q1’s base with the necessary bias voltage to drive it into the active region. The region of operation where the transistor is completely switched of is called cut-off region and the region of operation where the transistor is completely switched ON (like a closed switch) is called saturation region. The region in between cut-off and saturation is called active region. For a transistor amplifier to function properly, it should operate in the active region. 

C3 is the output DC decoupling capacitor. It prevents any DC voltage from entering into the succeeding stage from the present stage. If this capacitor is not used the output of the amplifier (Vout) will be clamped by the DC level present at the transistors collector.

R2 is the collector resistor and R3 is the emitter resistor.

Python: Reminder Alerts program

 This program will give you Attention message for every time interval you set in time.sleep(time_in_seconds)

import os

import time

from plyer import notification

 

if __name__ == "__main__":

    while True:

        notification.notify(title = "ATTENTION!!!",

        message = "Take a break! It has been an hour!",

         timeout = 10)

        time.sleep(3600)

Output:

Voltage follower using Op-amp IC TL082

 What is a Voltage Follower?

A voltage follower (also known as a buffer amplifier, unity-gain amplifier, or isolation amplifier) is an op-amp circuit whose output voltage is equal to the input voltage (it “follows” the input voltage). Hence a voltage follower op-amp does not amplify the input signal and has a voltage gain of 1.

The voltage follower provides no attenuation or amplification—only buffering.

A voltage follower circuit has a very high input impedance. This characteristic makes it a popular choice in many different types of circuits that require isolation between the input and output signal.

Below figures shows implementation of Voltage follower in Proteus design suite. You can see how the output voltage is approximately equal to the given input voltages.

Python: Anagram check program

 def anagram(s1, s2):

    #s1 and s2 are two strings which are to be checked for anagram

    s1 = s1.replace(' ', '').lower() # s1 is reaasigned with removing spaces and then made all lowercase 

    s2 = s2.replace(' ', '').lower() # s2 is reaasigned with removing spaces and then made all lowercase

    return sorted(s1) == sorted(s2)  # sorted both s1 and s2 and checked, if equal then returns True else False

print(anagram('this is right', 'is this right')) #printed True for anagram and False for not anagram

Output:

>>True

Python: Finding largest continuous sum in a list/array

 Problem Statement:

Given a list of integers (both positive and negative) find the largest continuous sum.

e.g. 

Input:

list1 = [1, 2, -1, 3, 4, 10, 10, -10, -1]

Output: 29

Solution:

def largest_cont_sum(list1):

    max_sum = current_sum = 0

    

    if len(list1) == 0:

        return "There is no any element in the List"

    

    for num in list1:

        current_sum = max(current_sum + num, num)

        max_sum = max(current_sum, max_sum)

    

    return max_sum

list1 = [1,2,-1,3,4,10,10,-10,-1]

print("The Largest continuous sum is:",largest_cont_sum(list1))

Output: The Largest continuous sum is: 29

Python: Find the missing element

 Problem Statement: Consider array/list of non-negative integers. The second array/list is formed by shuffling the elements of the first array/list and deleting a random element. Given these two arrays/lists, find which element is missing in second array.

e.g.

list1 = [1, 2, 3, 4, 5, 6]

list2 = [2, 5, 4, 6, 3]

here missing element is 1.

Solution:

def missing_ele(list1, list2):

    list1.sort()

    list2.sort()

    for num1, num2 in zip(list1, list2):

        if num1 != num2:

            return num1

    return list1[-1]

list1 = [1, 2, 3, 4, 5, 6]

list2 = [2, 4, 6, 3, 5]

print("Missing element is: ", missing_ele(list1, list2))

Output: Missing element is: 1

555 Timer as Monostable Multivibrator

Here, I have simulated a Monostable Multivibrator in Proteus design suite.

Python: Addition, Subtraction, Multiplication and Division using function

Program: 

#Addition function

def addition(a,b):

    c=a+b

    print("Addition= ",c)

print("Enter two numbers")

#Subtraction function

def subtraction(a,b):

    c=a-b

    print("Subtraction= ",c)

#Multiplication function

def multiplication(a,b):

    c=a*b

    print("Multiplication= ",c)

#Division function

def division(a,b):

    c=a/b

    print("Division= ",c)

a=float(input())

b=float(input())

addition(a,b)

subtraction(a,b)

multiplication(a,b)

division(a,b)

Output:

Enter two numbers

8

4

Addition=  12.0

Subtraction=  4.0

Multiplication=  32.0

Division=  2.0

Python: Addition of two numbers using function

Below is a simple addition program demonstrated using function addition. This program shows you how to use function in Python 

def addition(a,b): #This is funtion definitation

    c=a+b

    print("Addition = {}".format(c))

print("Enter two numbers to be added")

a=int(input())

b=int(input())

addition(a,b) #call the function addition() by passing two numbers a & b

Text in green are comments

Output:

Enter two numbers to be added

341

12

Addition = 353

Program for addition of two number using Python

 This is a simple program for addition of two numbers using Python.

Program takes two numbers as input from the user and prints the sum as output.

#Simple Program for addition of two number without using function

print("Enter two numbers to be added")

#int can have numbers in the range -2147483648 through 2147483647

a=int(input()) #takes first number as input from user

b=int(input()) #takes second number as input from user

c=a+b          #adds two numbers a & b and saves to c

print("Addition of numbers {} and {} is {}".format(a,b,c))

Text in green color shows the comments

Output:

Enter two numbers to be added

123

123

Addition of numbers 123 and 123 is 246

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