You have to design game “Rock Paper Scissors” on Logisim. See the attached document for more information.
Department of Computer Science Page1
Question 1
You have to design game “Rock Paper Scissors” on Logisim. To play and understand this
game click here.
There will be two players using their signs i.e. rock, paper and scissor.
Rock beats scissors, scissors beats paper, and paper beats rock. If both players select the
same sign, then it is a tie. Your circuit will determine the winner. The winner score is updated
and games will repeat. Your circuit should have two inputs for first and second players. Each
player should have 2 bits each. Your circuit must have two outputs Score and Win.
Your circuit should resemble like this:
https://www.afiniti.com/corporate/rock-paper-scissors
Department of Computer Science Page2
Guideline for designing this circuit.
Inputs Description
Reset reset player’s score to 0
Go evaluate A, B, C, and D
Left Player Left players is two bits each.
Right Player Right players is two bits each.
Clock update that player’s counter
You can either toggle the Clock line manually, or
enable a slow tick (e.g., 1 Hertz) in the simulator.
Outputs Description
Win\Tie (1 bit) set to 1 if this player wins or ties, 0 if this
player loses or if either inputs are illegal
Connect to LED for output
Win (1 bit) set to 1 if this player wins, 0 for all other
conditions
Connect to LED for output
Score (4 bit) Update 4 bit counter when player wins
Connect score to Hex Digital Display for
output
Hint-1: 4 bit Counter
You have to design your own 4 bit counter. Connect the output of a 4-bit Adder to a 4-bit
register. Then feedback the register’s value to the adder. This sub circuit has three
inputs: Increment, Reset, and Clock. There is one output, the 4-bit value stored in the register.
The counter should increment whenever Increment is high and upon the clock’s leading edge.
Any time Reset is high, the counter resets to 0 regardless of Increment or Clock. (You don’t
have to use built-in counter)
Hint-2
*For Gate Propagation Delays you can refer to 4 bit ripple adder.
Hint-3: K-Maps
Basically you have three states. E.g., if the value is 00 then it means it is rock. 10 means paper,
11 means scissors. 01 means illegal sign. You can derive equations using K-Maps. Construct
a K-map for the game’s four inputs (two inputs each for the two players) for the left
player’s Win/Tie and then another K-map for left player’s Win outputs. Then construct two
more K-maps for the right player’s Win/Tie and Win outputs.
Sign Bits representation
Rock 00
Paper 10
Scissors 11
