Interested to Buy Any Domain ? << Click Here >> for more details...
Answer Posted / rahul singhal
-----By RAHUL SINGHAL----
----This is the code of a FSM that implements a toll booth -
----controller
LIBRARY IEEE;
USE IEEE.STD_LOGIC_1164.ALL; ----using all functions of
specific package---
ENTITY tollbooth2 IS
PORT (Clock,car_s,RE : IN STD_LOGIC;
coin_s : IN STD_LOGIC_VECTOR(1 DOWNTO 0);
r_light,g_light,alarm : OUT STD_LOGIC);
END tollbooth2;
ARCHITECTURE Behav OF tollbooth2 IS
TYPE state_type IS
(NO_CAR,GOTZERO,GOTFIV,GOTTEN,GOTFIF,GOTTWEN,CAR_PAID,CHEATE
D);
------GOTZERO = PAID $0.00---------
------GOTFIV = PAID $0.05----------
------GOTTEN = PAID $0.10----------
------GOTFIF = PAID $0.15----------
------GOTTWEN = PAID $0.20---------
SIGNAL present_state,next_state : state_type;
BEGIN
-----Next state is identified using present state,car &
coin sensors------
PROCESS(present_state,car_s,coin_s)
BEGIN
CASE present_state IS
WHEN NO_CAR =>
IF (car_s = '1') THEN
next_state <= GOTZERO;
ELSE
next_state <= NO_CAR;
END IF;
WHEN GOTZERO =>
IF (car_s ='0') THEN
next_state <= CHEATED;
ELSIF (coin_s = "00") THEN
next_state <= GOTZERO;
ELSIF (coin_s = "01") THEN
next_state <= GOTFIV;
ELSIF (coin_s ="10") THEN
next_state <= GOTTEN;
END IF;
WHEN GOTFIV=>
IF (car_s ='0') THEN
next_state <= CHEATED;
ELSIF (coin_s = "00") THEN
next_state <= GOTFIV;
ELSIF (coin_s = "01") THEN
next_state <= GOTTEN;
ELSIF (coin_s <= "10") THEN
next_state <= GOTFIV;
END IF;
WHEN GOTTEN =>
IF (car_s ='0') THEN
next_state <= CHEATED;
ELSIF (coin_s ="00") THEN
next_state <= GOTTEN;
ELSIF (coin_s="01") THEN
next_state <= GOTFIV;
ELSIF (coin_s="10") THEN
next_state <= GOTTWEN;
END IF;
WHEN GOTFIF =>
IF (car_s ='0') THEN
next_state <= CHEATED;
ELSIF (coin_s = "00") THEN
next_state <= GOTFIF;
ELSIF (coin_s ="01") THEN
next_state <= GOTTWEN;
ELSIF (coin_s = "10") THEN
next_state <= GOTTWEN;
END IF;
WHEN GOTTWEN =>
next_state <= CAR_PAID;
WHEN CAR_PAID =>
IF (car_s = '0') THEN
next_state <= NO_CAR;
ELSE
next_state<= CAR_PAID;
END IF;
WHEN CHEATED =>
IF (car_s = '1') THEN
next_state <= GOTZERO;
ELSE
next_state <= CHEATED;
END IF;
END CASE;
END PROCESS;-----End of Process 1
-------PROCESS 2 for STATE REGISTER CLOCKING--------
PROCESS(Clock,RE)
BEGIN
IF RE = '1' THEN
present_state <= GOTZERO;
----When the clock changes from low to high,the state of
the system
----stored in next_state becomes the present state-----
ELSIF Clock'EVENT AND Clock ='1' THEN
present_state <= next_state;
END IF;
END PROCESS;-----End of Process 2-------
---------------------------------------------------------
-----Conditional signal assignment statements----------
r_light <= '0' WHEN present_state = CAR_PAID ELSE '1';
g_light <= '1' WHEN present_state = CAR_PAID ELSE '0';
alarm <= '1' WHEN present_state = CHEATED ELSE '0';
END Behav;
| Is This Answer Correct ? | 7 Yes | 0 No |
Post New Answer View All Answers
The answer to the above question is breaking the combinational circuit and pipelining it. What will be affected if you do this?
What is the function of ale in 8085 microprocessor?
What is stack pointer?
Write a program that will store the contents of an accumulator and flag register at locations 2000h and 2001h.
explain the flow of a typical instruction word
What is the bhe signal? Explain its significance?
What is the width of address bus?
What is the operating frequency of 8085?
How many instruction bits does 8085 processor support?
What are the widths of data bus (db) and address bus (ab) of 8085?
Byte wise what are the lengths of call and ret instructions?
Which interrupts are generally used for critical events?
How many i/o ports are present in the 8086?
Define the types of memory used in 8085 microprocessor?
Explain why do you use two ground pins in microprocessor 8086?
