Activity 5.3C – Additional Problems
Purpose
1. To understand and apply the steps necessary to program a PLD
2. To understand and apply the programming syntax of the WinCUPL language
3. To understand and apply the steps needed to program a programmable IC
Equipment
ICs: gal22v10D and other ICs as necessary
EMP 11
Breadboard and jumper wires
LEDs and current limiting resistors
5 volt power supply
Switches
Procedure
Design and create a solution to each of the following programs. Program a PLD with your solution; wire on a breadboard and then test your solution.
Your teacher will tell you the documentation necessary for you to pass in to receive credit for the solution of these problems.
1. A water well-pump is to be turned on if the water level in any two or more of the three holding tanks it supplies is low. Sensors in each of the tanks generate a logical 0 if the level of the tank is low. Using a PLD; design, build and test a logic circuit that turns the pump on by generating a logical 1 in response to the inputs. Test this circuit by using a red LED to indicate the well-pump turning on.
2. An automobile ignition system is designed to either start or sound a buzzer by monitoring the following: the driver’s seatbelt, the doors, the transmission and the key position. The system has been designed as follows:
· The driver’s seatbelt registers a 1 if fastened and a 0 if not;
· The doors register a 1 if all are closed, and a 0 if not;
· The transmission registers a 1 if engaged (or in neutral), and a 0 if in park;
· The key registers a 1 if turned to the start position and a 0 for any other condition.
The car will start ONLY if the driver’s seatbelt is fastened, all doors are shut, the transmission is in park, and the key has been turned to the start position.
A buzzer will sound if the key is turned to the start position and any of the other conditions are not met.
Using a PLD design, build and test a circuit using an LED to indicate when the car starts and a buzzer (or another LED) for the warning condition.
3. Using a PLD, design a combinational logic circuit that will compare two-two bit binary numbers (X and Y) and display on a seven-segment display an E when X and Y are equal, an L when X is less than Y and a G when X is greater than Y. Your design needs to output the correct logic for the segments a, b, c, d, e, f, and g on the display.
4. Using a PLD, design, build and test a combinational logic circuit that will take a binary input and output on a seven-segment display your birth month, birthday and last 2 digits of your birth year. For example, if your birthday is January 23, 1967 (01-23-67), when the input signal is 000 the display is “0”, 001 displays “1”, 010 displays “-“, 011 displays “2”, etc. Your design needs to output the correct logic for the segments a, b, c, d, e, f, and g on the display.
5. The Center for Disease Control (CDC) Laboratory in Atlanta Georgia is by necessity among the most secure labs in the world. The consequences of a dangerous virus getting out of the lab are monumental. The engineering team working there has created a three-door air lock and ventilation system that will allow employees to enter an exit the building without the chance that air from inside the building will combine directly with the outside air for any significant amount of time. Each of the doors has an electronic lock similar to the ones in apartment buildings where someone is “buzzed in”. The buzzing noise comes from the electronic lock that is held open as long as the apartment dweller is pushing a button on the wall of their apartment. A guard with a master control switch that will unlock or lock all of the doors is observing the flow of workers in and out of the building via video camera. As long as the guard watching the workers come and go sets the control switch to “unlock” or “1”, workers are allowed to come and go as they please without the need to “buzz” individual doors. The problem is that as long as the three doors are never open or partially open at the same time the air lock will function properly. If any two doors are opened at the same time the third should automatically lock itself. The doors close automatically and have switches in them to let the control circuit know if the door is open or closed. A fourth output of this circuit is an alarm light that Lights up if ever the three doors are open at the same time. The doors are set 15 feet apart. This is so that a person simply walking into or out of the building will not experience a locked door as they walk through because the door “behind” them in theory will have swung closed by the time they reach the next door.
Things to Keep in Mind:
· If the guard’s switch (key) is “0” no one can get in, all doors are locked
· If a door switch is “0” then the door is closed (0 = door closed)
· If a “Buzz Lock” receives a “1” it is unlocking a door (1 = door unlocked)
· Doors are to unlock or go into “automatic lock and unlock mode” if the security guard has pressed the “unlock switch” (A ”1” on the guard switch means “automatic mode”)
· If any two doors are open (door switch = 1) at the same time, the third should lock (lock output = 0) automatically.
· If ever the three doors are open at the same time, “EMERGENCY” alarm light should be on
Extension Activity:
NOTE: Once you have turned in your assignment add electronic control features to the system that have not been specified, like lights that show the guard the status of each door and lock at any given time. Or a high security over-ride mode that will only allow one door to be unlocked at a time and the guard has the option with the flip of a switch to set the doors on low or high security.