ECE380-Lab 5 Adders/Subtractor Solved

In this lab, you will use the Quartus II software package to design and simulate behavioral adder, ripple carry adder, and LPM_ADD_SUB implementation. You are required to print the Megafunction schematic or VHDL files for Designs A, B, and C.  

 

In the three designs, view the compilation report file (*.rpt) when you compile each design for the DE1 device. In the DEVICE SUMMARY section, note the number of logic cells (LCs) required for each design. Write the number you noted in your report.

 

1. Implement Design A  
 

Create the test vectors in the prelab to verify the correctness of the circuit in functional simulations.

 

Download your design to the Cyclone® V 5CSEMA5F31C6 device on the DE1 board. Use inputs SW[9..6] (SW[6] is the LSB) for the X input and SW[5..2] (SW[2] is the LSB)  for the Y input. Use SW[0] for Cin. Use LEDs LEDG[3..0] (LEDG[0] is the LSB) for the circuit output S. Use LEDs LEDR[9] and LEDR[8] for Cout and Over, respectively.

 

By using the created test vectors, verify that Design A is operational on the DE1 board. Receive TA initials when you complete verifications.

 

2. Implement Design B   
3. Create the test vectors in the prelab to verify the correctness of the circuit in functional simulations.

 

Download your design to the Cyclone® V 5CSEMA5F31C6 device on the DE1 board. Use inputs SW[9..6] (SW[6] is the LSB) for the X input and SW[5..2] (SW[2] is the LSB)  for the Y input. Use SW[0] for Cin. Use LEDs LEDG[3..0] (LEDG[0] is the LSB) for the circuit output S. Use LEDs LEDR[9] and LEDR[8] for Cout and Over, respectively.

 

By using the created test vectors, verify that Design B is operational on the DE1 board. Receive TA initials when you complete verifications.

 

4. Implement Design C 
Create the test vectors shown below to verify the correctness of the circuit in functional simulations.  

 

 

 

6

Input 
Add_Sub 
Add
add
add
add
add
add
sub
sub
Sub
Input 
Cin 
1
1
0
1
0
0
1
1
1
Input 
X
0x3
0xB
0xB
0x6
0x6
0xA
0xB
0x5
0xC
Input 
Y
0x2
0x3
0xA
0x2
0xE
0xE
0x2
0x2
0x5
Output 
S
 
 
 
 
 
 
 
 
 
Output 
Cout 
 
 
 
 
 
 
 
 
 
Output 
Over 
 
 
 
 
 
 
 
 
 
 

 

Download your design to the Cyclone® V 5CSEMA5F31C6 device on the DE1 board. Use inputs SW[9..6] (SW[6] is the LSB) for the X input and SW[5..2] (SW[2] is the LSB)  for the Y input. Use SW[0] for Cin. Use LEDs LEDG[3..0] (LEDG[0] is the LSB) for the circuit output S. Use LEDs LEDR[9] and LEDR[8] for Cout and Over, respectively.

 

By using the created test vectors, verify that Design C is operational on the DE1 board.

Receive TA initials when you complete verifications. 


Homework 
 

Q1 Show that the following circuit implements a full adder.  

 

You need to show 𝑐𝑐𝑖𝑖+1 =𝑥𝑥𝑖𝑖𝑦𝑦𝑖𝑖 +𝑥𝑥𝑖𝑖𝑐𝑐𝑖𝑖 +𝑦𝑦𝑖𝑖𝑐𝑐𝑖𝑖 and 𝑠𝑠𝑖𝑖 =𝑐𝑐𝑖𝑖⨁𝑥𝑥𝑖𝑖⨁𝑦𝑦𝑖𝑖 based on the following schematic of the full adder.  

 

 

 

 

  

 

 

 

Q2 Use the truth table to prove the validity of the expression: Overflow =𝑐𝑐𝑛𝑛 ⊕𝑐𝑐𝑛𝑛−1 for addition of n-bit signed numbers.  

 

Hint: construct first the truth table for both Overflow and 𝑐𝑐𝑛𝑛, as a function of 𝑥𝑥𝑛𝑛−1, 𝑦𝑦𝑛𝑛−1, and 𝑐𝑐𝑛𝑛−1.  

 

 

Q3 Prove the validity of the expression for the overflow flag in the addition of n-bit signed numbers:   

𝑓𝑓=𝑥𝑥𝑛𝑛−1⨁𝑦𝑦𝑛𝑛−1⨁𝑠𝑠𝑛𝑛−1⨁𝑐𝑐𝑛𝑛