CMPEN 270 Laboratory 8 

CMPEN 270 Laboratory 8 

In this lab you will work on:
1. Sequential Logic
2. Latches and Flip-Flops
3. Conversions
Conversion Example:
In this lab you will need to do Flip Flop conversions. Here we will go over an example of how to convert a
T-FF to a JK-FF. (Q represents the current Q value and Q+ represents the next Q value)
The first step we want to do is to write out the truth table for JK-FF.
J K Q Q+
0 0 0 0
0 0 1 1
0 1 0 0
0 1 1 0
1 0 0 1
1 0 1 1
1 1 0 1
1 1 1 0
Our next step is to look at the T-FF excitation table. We know that is Q is not changing then T = 0 and if Q
does change then T = 1.
Q Q+ T
0 0 0
0 1 1
1 0 1
1 1 0
CMPEN    270    Laboratory    8 2020
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Next we want to combine these two tables.
J K Q Q+ T
0 0 0 0 0
0 0 1 1 0
0 1 0 0 0
0 1 1 0 1
1 0 0 1 1
1 0 1 1 0
1 1 0 1 1
1 1 1 0 1
Next we want to find an equation for T using J, K, and Q as inputs. To do this we will use a kmap.

Problem Description:
EDA Playground link with starter files: https://www.edaplayground.com/x/bJft
This week's lectures will focus on Sequential Logic and Latches and Flip Flops. One important tool you
will need to know is how to convert from one flip-flop/latch to another. In this lab you will be tasked
with converting an SR-Flip Flop to a JK-Flip Flop.
Project Requirements:
SR_FF.v
• You will need to create a module that acts like an SR-FF name this file SR_FF.v
• SR_FF.v will have four inputs S, R, clock, and reset and two output Q and Qbar
• when reset is on (reset = 1) then you must set Q = 0
• when reset is off (reset = 0) then you must set Q following the SR-FF which the truth
table is shown below
• for the lab we will use Q=0 as default in the case of the forbidden state
CMPEN    270    Laboratory    8 2020
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Reset S R Q Qbar
1 d d 0 1
0 0 0 Last Q Last Qbar
0 0 1 0 1
0 1 0 1 0
o 1 1 X X
design.v
• You will need to create a top level module that converts the SR-Latch to a JK-FF, name
this file design.v
• design.v will have four inputs J, K, clock, and reset and two outputs Q and Qbar
Your Project should follow the following diagram:
SR-FF
J
K
your
conversion
equations
q
design.v
q'
CMPEN    270    Laboratory    8 2020
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Below is the SR-FF excitation table which will help you when finding the conversion.
Solution:
Your solution will be auto graded by the test bench script. You will pass the testbench if your output
truth table matches a JK-FF truth table. Below is how your truth table will look.