Submitted By:
Wajahat Ali Butt 107
Hashir Badar 113
Muhammad Fahad Shabbir 127
Muhammad Safeer 134
DESIGN SPECIFICATIONS
We have designed this machine for three products. The user will first select
one of the three products. The machine will tell him the price of the product.
Then he will enter money. If the amount of money entered is equal to the
price of the product then product will be issued. But if the amount of money
entered is greater than the price then product will be issued as well as change
will be returned. The return of change as well as the issue of product is
indicated by LED. The product selected as well as its price is displayed on 7
segment LED display. The product is selected as well as money is entered
through switches. There is a reset button to reset the machine to idle state.
The 1st product has Rs.1 , 2nd product has Rs.2 fare and 3rd product has Rs.3.
The three products are represented in binary no. as 001,010,100 respectively.
The user is allowed to enter Rs. 1, Rs.2, or Rs.3 coin which are represented
in binary as 0 or 1.
STATE DIAGRAM
`
Free
state
Product_
A_State
Product_
B_State
Product_
C_State
(Rs.3)
(Rs.4)
(Rs.5)
Change
State
VERILOG CODING
`timescale 1ns / 1ps
///////////////////////////////////////////////////////////
///////////////////////
// Company:
// Engineer:
//
// Create Date:
00:10:36 07/11/2008
// Design Name:
// Module Name:
vend
// Project Name:
// Target Devices:
// Tool versions:
// Description:
//
// Dependencies:
//
// Revision:
// Revision 0.01 - File Created
// Additional Comments:
//
///////////////////////////////////////////////////////////
///////////////////////
module vend(
//Inputs
clk,
reset,
RS1,
RS3,
RS2,
product,
//
//
//
//
//
internal clock (50
reset variable
Rupees 1 coin (dip
Rupees 3 coin (dip
Rupees 2 coin (dip
//Outputs
// 2nd SEVEN Segment
LED_a2,
LED_b2,
LED_c2,
LED_d2,
LED_e2,
LED_f2,
MHz)
switch)
switch)
switch)
//
LED_g2,
1 st SEVEN Segment
LED_a1,
LED_b1,
LED_c1,
LED_d1,
LED_e1,
LED_f1,
LED_g1,
);
//*********************************************************
*******************
// ASSIGNING each variable as input or
input clk;
input reset;
input RS1;
input RS2;
input RS3;
input[2:0] product;
//
output
output
output
output
output
output
output
LED_a2;
LED_b2;
LED_c2;
LED_d2;
LED_e2;
LED_f2;
LED_g2;
output
output
output
output
output
output
output
LED_a1;
LED_b1;
LED_c1;
LED_d1;
LED_e1;
LED_f1;
LED_g1;
output LED_timer;
// declaring output as reg
reg LED_a2;
output.
reg
reg
reg
reg
reg
reg
LED_b2;
LED_c2;
LED_d2;
LED_e2;
LED_f2;
LED_g2;
reg
reg
reg
reg
reg
reg
reg
LED_a1;
LED_b1;
LED_c1;
LED_d1;
LED_e1;
LED_f1;
LED_g1;
reg
reg
reg
reg
[3:0]t_money;
[3:0]r_money;
[3:0]first_digit;
[3:0]second_digit;
reg temp1;
for toggling
reg temp2;
reg temp3;
// temporary reg variables
reg [1:0]pres_state, next_state;
parameter
FREE_STATE= 3'd0,
PRODUCT_A_STATE=3'd1,
PRODUCT_B_STATE = 3'd2,
PRODUCT_C_STATE= 3'd3,
CHANGE_STATE
= 3'd4;
//*********************************************************
*******************
always@(posedge clk or negedge reset)
begin
if (reset == 0)
pres_state <= FREE_STATE;
else
pres_state <= next_state;
end
//*********************************************************
*******************
always@ (posedge clk)
begin
case(pres_state)
FREE_STATE:
begin
case(product)
3'b001:
next_state<=PRODUCT_A_STATE;
3'b010:
next_state<=PRODUCT_B_STATE;
3'b100:
next_state<=PRODUCT_C_STATE;
default:
next_state <= FREE_STATE;
endcase
end
next_state<=PRODUCT_A_STATE:
begin
if(t_money<3)
next_state <=PRODUCT_A_STATE;
else if(t_money >=3 )
next_state <= CHANGE_STATE;
end
next_state<=PRODUCT_B_STATE:
begin
if(t_money<4)
next_state <=PRODUCT_B_STATE;
else if(t_money >=4)
next_state <= CHANGE_STATE;
end
next_state<=PRODUCT_C_STATE:
begin
if(t_money<5)
next_state <=PRODUCT_C_STATE;
else if(t_money >=5)
next_state <= CHANGE_STATE;
end
CHANGE_STATE:
begin
next_state <= CHANGE_STATE;
end
endcase
end
//*********************************************************
*******************
always@ (posedge clk)
begin
case(pres_state)
FREE_STATE:
begin
if (reset == 0)
begin
temp3 <= 0;
temp2 <= 0;
temp1 <= 0;
if(product==3'b000)
r_money <= 0;
else if(product==3'b001)
r_money <= 3;
else if(product==3'b010)
r_money <= 4;
else if(product==3'b100)
r_money <= 5;
first_digit <= 4'd0;
second_digit <= 4'd0;
end
end
PRODUCT_A_STATE:
begin
if(RS1 == !temp1)
begin
temp1 <= !temp1;
t_money <= t_money + 1;
r_money <= r_money - 1;
end
else if(RS2 == !temp2)
begin
temp2 <= !temp2;
t_money <= t_money + 2;
r_money <= r_money - 2;
end
else if(RS3 == !temp3)
begin
temp3 <= !temp3;
t_money <= t_money + 3;
r_money <= r_money - 3;
end
second_digit <=r_money;
end
PRODUCT_B_STATE:
begin
if(RS1 == !temp1)
begin
temp1 <= !temp1;
t_money <= t_money + 1;
r_money <= r_money - 1;
end
else if(RS2 == !temp2)
begin
temp2 <= !temp2;
t_money <= t_money + 2;
r_money <= r_money - 2;
end
else if(RS3 == !temp3)
begin
temp3 <= !temp3;
t_money <= t_money + 3;
r_money <= r_money - 3;
end
second_digit <=r_money;
end
PRODUCT_C_STATE:
begin
if(RS1 == !temp1)
begin
temp1 <= !temp1;
t_money <= t_money + 1;
r_money <= r_money - 1;
end
else if(RS2 == !temp2)
begin
temp2 <= !temp2;
t_money <= t_money + 2;
r_money <= r_money - 2;
end
else if(RS3 == !temp3)
begin
temp3 <= !temp3;
t_money <= t_money + 3;
r_money <= r_money - 3;
end
second_digit <=r_money;
end
CHANGE_STATE:
begin
first_digit<=12;
second_digit<=0
end
;
endcase
end
//*********************************************************
*******************
//display on 7segments
always @(first_digit)
begin
case(first_digit)
4'b0000 :
begin
LED_a1 <= 1'b0; // for displaying
nothing at seven - segment
LED_b1 <= 1'b0;
LED_c1 <= 1'b0;
LED_d1 <= 1'b0;
LED_e1 <= 1'b0;
LED_f1 <= 1'b0;
LED_g1 <= 1'b0;
end
4'b1100 :
begin
LED_a1 <= 1'b1; // display C at
seven - segment
LED_b1
LED_c1
LED_d1
LED_e1
LED_f1
LED_g1
<=
<=
<=
<=
<=
<=
1'b0;
1'b0;
1'b1;
1'b1;
1'b1;
1'b0;
end
default :
begin
LED_a1 <= LED_a1; // maintain
output LEDs
LED_b1
LED_c1
LED_d1
LED_e1
LED_f1
LED_g1
end
<=
<=
<=
<=
<=
<=
LED_b1;
LED_c1;
LED_d1;
LED_e1;
LED_f1;
LED_g1;
endcase
end
//*********************************************************
*******************
always @(second_digit)
begin
case(second_digit)
4'b0000 :
begin
LED_a2 <= 1'b1; // 0 display at seven segment
LED_b2
LED_c2
LED_d2
LED_e2
LED_f2
LED_g2
end
<=
<=
<=
<=
<=
<=
1'b1;
1'b1;
1'b1;
1'b1;
1'b1;
1'b0;
4'b0001 :
begin
LED_a2 <= 1'b0; // 1 display at seven segment
LED_b2
LED_c2
LED_d2
LED_e2
LED_f2
LED_g2
end
<=
<=
<=
<=
<=
<=
1'b1;
1'b1;
1'b0;
1'b0;
1'b0;
1'b0;
4'b0010 :
begin
LED_a2 <= 1'b1; // 2 display at seven segment
LED_b2
LED_c2
LED_d2
LED_e2
LED_f2
LED_g2
end
<=
<=
<=
<=
<=
<=
1'b1;
1'b0;
1'b1;
1'b1;
1'b0;
1'b1;
4'b0011 :
begin
LED_a2 <= 1'b1; // 3 display at seven segment
LED_b2
LED_c2
LED_d2
LED_e2
LED_f2
LED_g2
end
<=
<=
<=
<=
<=
<=
1'b1;
1'b1;
1'b1;
1'b0;
1'b0;
1'b1;
4'b0100 :
begin
LED_a2 <= 1'b0; // 4 display at seven segment
LED_b2
LED_c2
LED_d2
LED_e2
LED_f2
LED_g2
<=
<=
<=
<=
<=
<=
1'b1;
1'b1;
1'b0;
1'b0;
1'b1;
1'b1;
end
4'b0101 :
begin
LED_a2 <= 1'b1; // 5 display at seven segment
LED_b2
LED_c2
LED_d2
LED_e2
LED_f2
LED_g2
end
<=
<=
<=
<=
<=
<=
1'b0;
1'b1;
1'b1;
1'b0;
1'b1;
1'b1;
default :
begin
LED_a2 <= LED_a2; // maintain
output LEDs
LED_b2
LED_c2
LED_d2
LED_e2
LED_f2
LED_g2
end
endcase
end
endmodule
<=
<=
<=
<=
<=
<=
LED_b2;
LED_c2;
LED_d2;
LED_e2;
LED_f2;
LED_g2;