PROJECT 5: GAME TRACKER (FSM)

DIGITAL LOGIC SYSTEMS 
PROJECT 5: GAME TRACKER (FSM)

The synchronous circuit game tracks after the results of the game rounds
of two players. At each clock cycle t, two players (player-0 and player-1)
submit their round-scores as the inputs X[0](t) and X[1](t), respectively.
The game continues until one of the players gains a 2 point advantage relative
to his opponent, after which a new game is initialized.
The circuit must output a notification about the winning player: If at
time t, player i gains a score which causes him to lead by 2 points, then the
output of the circuit must be y[i](t) = 1, y[1 − i](t) = 0. Pay attention that
the output responds immediately to the current input! In all other cases, the
output is zero.
Specifications
Inputs: CLK(t), reset(t) ∈ {0, 1}; X[1 : 0](t) ∈ {0, 1}
2
Outputs: Y [1 : 0](t) ∈ {0, 1}
2
Functionality: Given a clock cycle t, let τ (t) ∈ {0, 1} indicate whether this
is a first clock cycle of a game. Formally
τ (t) = 1 ⇔ reset(t) = 1 or y(t − 1) 6= 02
The outputs Y [1 : 0](t) must respect the following:
Y [0](t) =1 ⇔
X
t
t
0=max{t
00|τ(t
00)=0}
X[0](t
0
) − X[1](t
0
) = 2
Y [1](t) =1 ⇔
X
t
t
0=max{t
00|τ(t
00)=0}
X[1](t
0
) − X[0](t
0
) = 2
See example below for the execution of 16 clock cycles
Table 1. Simulation example of game synchronous circuit
t 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
X[1 : 0](t) 01 01 00 10 11 00 10 10 01 01 01 10 00 01 01 00
reset(t) 1 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0
τ (t) 1 0 1 0 0 0 0 1 0 0 0 1 1 0 0 1
Y [1 : 0](t) 00 01 00 00 00 00 10 00 00 00 01 00 00 00 01 00
1
DLS: PROJECT 5 2
Your Assignment
The final goal is to implement game synchronous circuit, which satisfies
the above specifications. Only the Logisim file is to be submitted, however,
you are advised to follow the following guidelines
(1) Design the FSM(game). Important notice: there is a reset input
signal, however you do not need to account for it in your state
diagram. Whenever reset(t)=1, it means that the state at time t is
your initial state.
(2) Synthesize FSM(game) using as few flip-flops and logical gates as you
can. Assume that the cost of a flip-flop is 100 and the cost of a basic
combinational gate is 1, this means that you should prefer shorter
state encodings.
(3) Your implementation must be contained within the provided
template game.circ file. Begin with implementing the combinational circuits Cdelta and Clambda. Then, to complete the design:
instantiate Cdelta and Clambda circuits in the game circuit - using
the canonical form of a synchronous circuit. Make sure to modify the initial state string in the existing MUX (for a proper
initialization).
(4) You must not modify the IO ports of the game circuit. However, you
should modify the data-bits of the S,NS buses and of the register
according to the number of bits you use for the state encoding.
Submission Instructions
(1) Submit a single Logisim (“.circ”) file. No prints/screenshots. This
file must be named ID1 ID2 game.circ with ID1 and ID2 replaced
by each partner’s 9 digit ID number.
(2) Use the provided template game.circ file as a template, and implement your designs in the circuit named game. Do not move or modify
the input/output ports, the “blackbox” layout, and the names of the
existing circuits!
(3) You are not allowed to create “helper-circuits”. All your design must
be contained in the Cdelta, Clambda and game circuits. You should
modify all the S,NS related IO ports in the provided circuits, but
you must not modify the IO ports of the game circuit.
(4) Only one of the students in a pair needs to upload the submission.
Do not upload the same work twice!
(5) You may not use gates with fan-in larger than 2. Exception is for
Logisim’s MUX2:1, with a fan-in of 3, however is allowed to be used.
(6) You are allowed to use the data-bits attribute of the gates to perform
bitwise operations.
(7) You are allowed to use “Arithmetic” library of Logisim (Adder,Shifter
circuits). as well as the “Plexers” library.
(8) Do not use extra modules from the “Memory” Library. We already
placed a register in the game circuit. You only need to modify its
data-bits attribute.