What is the need for port?

1140

I have code and test bench however it is not working porperly. Need help to get it working. 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; \\i need to define the registers as change,coin and vend reg vend; reg [2:0]change; wire [2:0]coin; \\my 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 module test; \\THE INPUT IN THE FSM MODULE ARE REG HERE reg clock,reset; reg [2:0]coin; \\THE OUTPUT IN THE FSM MODULE ARE WIRES HERE wire vend; wire [2:0]state; wire [2:0]change; \\THE PARAMETERS AGAIN FOR THE COIN AND STATE 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; 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; \\I MONITOR THE TIME,DRINK,RESET,CLOCK,STATE AND CHANGE FOR CHANGES. initial begin $display("Time\tcoin\tdrink\treset\tclock\tstate\tchange"); $monitor("%g\t%b\t%b\t%b\t%b\t%d\t% d",$time,coin,vend,reset,clock,state,change); \\NEW FEATURE: MY MACHINE HAS THE FACILITY TO DUMP VARIABLES SO THAT \\ I CAN VIEW THEM USING A VCD VIEWER. $dumpvars; $dumpfile("file.vcd"); // Dump output file. \\THIS IS WHERE THE COINS ARE ADDED. clock=0; reset=1; \\FIRST LETS RESET THE MACHINE #2 reset=0; coin=NICKEL; \\CHECK FOR STATE 1 #2 reset=1; coin=2’b00; #2 reset=0; coin=DIME; \\RESET AGAIN AND CHECK FOR STATE 2 #2 reset=1; coin=2’b00; #2 reset=0; \\RESET AGAIN AND CHECK FOR STATE 5 coin=QUARTER; #2 reset=1; coin=2’b00; #2 reset=0; \\RESET AGAIN AND CHECK FOR STATE 5 coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 reset=1; coin=2’b00; #2 reset=0; \\RESET AGAIN AND CHECK FOR STATE 5 AND SO ON coin=NICKEL; #2 coin=DIME; #2 coin=DIME; #2 reset=1; coin=2’b00; #2 reset=0; coin=NICKEL; #2 coin=DIME; #2 coin=QUARTER; #2 reset=1; coin=2’b00; #2 reset=0; coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 coin=DIME; #2 reset=1; coin=2’b00; #2 reset=0; coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 coin=NICKEL; #2 coin=DIME; #2 reset=1; coin=2’b00; #2 reset=0; coin=NICKEL; #2 coin=NICKEL; #2 coin=QUARTER; #2 reset=1; coin=2’b00; #2 reset=0; coin=NICKEL; #2 coin=QUARTER; #2 reset=1; coin=2’b00; #2 $finish; end \\THE CLOCK NEEDS TO TICK EVERY 2 TIME UNIT always #1 clock=~clock; //always @(state) // coin=!coin; initial begin if (reset) coin=2’b00; end \\THIS IS WHERE I INSTANTIATE THE MACHINE fsm inst1(clock,reset,coin,vend,state,change); endmodule

3864

Explain xthl, daa, rc instructions.

1158

What are the types of interrupts from type 0 to 4

975

What happens when reset in(low) signal goes low?

1177

Which are sixteen bit registers of 8085?

1040

Which interrupt has highest priority?

1116

State the differences between a procedure and a macro.

1227

How many instruction bits does 8085 processor support?

1100

What are the steps involved in a fetch cycle

1043

Explain what is microcontroller?

1125

How is EPROM generally erased

1129

What jobs alu of 8085 can perform?

1280

What location code memory space and data memory space begins?

2117

Why 8051 is called 8 bit microcontroller?

1368