create a vending machine using verilog It will accept Quarte

create a vending machine using verilog. It will accept Quarters, nickels, and dimes. the cost of a drink is 20 cents.the machine should dispense proper change, then dispense the drink. use the following truth tables to create your code:

Solution

\\\\module name
module fsm(clock,reset,coin,vend,state,change);
\\\\these are the inputs and the outputs.
input clock;
input reset;
input [2:0]coin;
output vend;
output [2:0]state;
output [2:0]change;
\\\ eeded to define the registers as change,coin and vend
reg vend;
reg [2:0]change;
wire [2:0]coin;
\\\\The coins are declared as parameters to make reading better.
parameter [2:0]NICKEL=3’b001;
parameter [2:0]DIME=3’b010;
parameter [2:0]NICKEL_DIME=3’b011;
parameter [2:0]DIME_DIME=3’b100;
parameter [2:0]QUARTER=3’b101;
\\\\MY STATES ARE ALSO PARAMETERS . I DONT WANT TO MAKE YOU READ
\\\\IN MACHINE LANGUAGE
parameter [2:0]IDLE=3’b000;
parameter [2:0]FIVE=3’b001;
parameter [2:0]TEN=3’b010;
parameter [2:0]FIFTEEN=3’b011;
parameter [2:0]TWENTY=3’b100;
parameter [2:0]TWENTYFIVE=3’b101;
\\\\AS ALWAYS THE STATES ARE DEFINED AS REG
reg [2:0]state,next_state;
\\\\MY MACHINE WORKS ON STATE AND COIN
always @(state or coin)
begin
next_state=0; \\\\VERYFIRST NEXT STATE IS GIVEN ZERO
case(state)
IDLE: case(coin) \\\\THIS IS THE IDLE STATE
NICKEL: next_state=FIVE;
DIME: next_state=TEN;
QUARTER: next_state=TWENTYFIVE;
default: next_state=IDLE;
endcase
FIVE: case(coin) \\\\THIS IS THE SECOND STATE
NICKEL: next_state=TEN;
DIME: next_state=FIFTEEN;
QUARTER: next_state=TWENTYFIVE; //change=NICKEL
default: next_state=FIVE;
endcase
TEN: case(coin) \\\\THIS IS THE THIRD STATE
NICKEL: next_state=FIFTEEN;
DIME: next_state=TWENTY;
QUARTER: next_state=TWENTYFIVE; //change=DIME
default: next_state=TEN;
endcase
FIFTEEN: case(coin) \\\\THIS IS THE FOURTH STATE
NICKEL: next_state=TWENTY;
DIME: next_state=TWENTYFIVE;
QUARTER: next_state=TWENTYFIVE; //change==NICKEL_DIME
default: next_state=FIFTEEN;
endcase
TWENTY: case(coin) \\\\THIS IS THE FIFTH STATE
NICKEL: next_state=TWENTYFIVE;
DIME: next_state=TWENTYFIVE; //change=NICKEL
QUARTER: next_state=TWENTYFIVE; //change==DIME_DIME
default: next_state=TWENTY;
endcase
TWENTYFIVE: next_state=IDLE; \\\\THE NEXT STATE HERE IS THE RESET
default : next_state=IDLE;
endcase
end
always @(clock)
begin \\\\WHENEVER I GIVE A RESET I HAVE TO MAKE THE STATE TO IDLE AND VEND TO 1
if(reset) begin
state <= IDLE;
vend <= 1’b0;
// change <= 3’b000;
end \\\\THE CHANGE ALSO HAS TO BECOME NONE
else state <= next_state;
case (state) \\\\HERE WE DECIDE THE NEXT STATE
\\\\ALL THE STATES ARE DEFINED HERE AND THE OUTPUT IS ALSO GIVEN
IDLE: begin vend <= 1’b0; change <=3’d0; end
FIVE: begin vend <= 1’b0; if (coin==QUARTER) change <=NICKEL; else change <=3’d0; TEN: begin vend <= 1’b0; if (coin==QUARTER) change <=DIME; else change <= 3’d0; FIFTEEN : begin vend <= 1’b0; if (coin==QUARTER) change <=NICKEL_DIME; else change TWENTY : begin vend <= 1’b0; if (coin==DIME) change <=NICKEL; else if (coin==QUARTER) TWENTYFIVE : begin vend <= 1’b1; change <=3’d0; end
default: state <= IDLE;
endcase
end
endmodule