Traffic Light Controller

 

 

 

Rule 

1) Traffic Light는 차량이 없을 때 초록색에서 노란색을 거쳐 빨간색으로 변한다.

2) Moore FSM 사용

 

 

---

Next State Logic

module ns_logic(TA,TB,state,next_state);

input [1:0] TA,TB;

 

input [1:0] state;
output [1:0] next_state;
wire w0,w1;

_xor2 U0_xor2(.a(state[1]),.b(state[0]),.y(next_state[1]));

_and3 U1_and3(.a(~(state[1])),.b(~(state[0])),.c(~(TA)),.y(w0));
_and3 U2_and3(.a(state[1]),.b(~(state[0])),.c(~(TB)),.y(w1));
_or2 U3_or2(.a(w0),.b(w1),.y(next_state[0]));

endmodule

 

 

---

 

이를 토대로한 Bool 식

 

 

Output Logic

os_logic(state,LA,LB);

input [1:0] state;
output [1:0] LA,LB;

assign LA[1] = state[1];
_and2 U0_and2(.a(~state[1]),.b(state[0]),.y(LA[0]));
assign LB[1] = ~state[1];
_and2 U1_and2(.a(state[1]),.b(state[0]),.y(LB[0]));

endmodule

 

 

 

---

 

Traffic Light Controller

module tl_cntr(clk,reset_n,TA,TB,LA,LB);

input clk,reset_n,TA,TB;
output [1:0] LA,LB;

wire [1:0] state,next_state;

 

ns_logic U0_ns_logic(.TA(TA),.TB(TB),.state(state),.next_state(next_state));
os_logic U1_os_logic(.state(next_state),.LA(LA),.LB(LB));
_register2_r U2_register2_r(.clk(clk),.reset_n(reset_n),.d(next_state),.q(state)); 

endmodule