need to create a state transition diagram
ELEC2042 2020 Session 2
Assignment 1 (Version 1)
Due: Friday 11th September 2020
This assignment is the simple design task. You are given a problem and need to create a state
transition diagram, truth tables, Karnaugh maps and finally minimum Sum-Of-Products equations
to solve the problem.
You are to design the control system for a simple metro train system. You are responsible for the
doors on the train, as well as the wheel motors on the train.
The train will start in a stationary state. When you have initialised the train your system will signal
that the train is ready to proceed. The train will stay stationary until your system receives a proceed
signal. You will then start the motors at that point. The motors have four speeds: stop, slow forward
adjust speed, medium forward speed and full forward speed. When the proceed signal is removed
your system will need to slow the motors to slow forward speed until you are aligned with the doors
as indicated by the aligned signal. At that time you will need to stop the motors until the Current
Speed input has become stationary.
Once the train is stationary at the station your system will need to open the doors and signal a timer
to start. When the timer has expired your system should close the doors, and signal you are ready to
proceed. You will then receive a proceed signal and the whole process will repeat.
The inputs to your system are:
| Signal | Value | Meaning |
| Proceed | 0 | Do NOT Proceed |
| 1 | Train May Proceed | |
| Aligned | 0 | Train is NOT currently aligned with the platform doors |
| 1 | Train is currently aligned with the platform doors | |
| DoorsOpen | 00 | Doors are closed and locked |
| X1 | Doors are partially opened | |
| 10 | Doors are fully opened | |
| CurrentSpeed | 00 | Train is stationary |
| 01 | Train is moving at slow adjust speed | |
| 10 | Train is moving medium | |
| 11 | Train is at full speed | |
| TimerExpired | 0 | Timer is Counting |
| 1 | Timer is at Terminal Count and has stopped counting |
ELEC2042 1 of 4 2020 Session 2
Macquarie University Assignment 1 v1
Your system has to drive the following outputs. You must supply a truth table, Karnaugh map and
minimal sum-of-product equations for each of these outputs.
Ready to Proceed Output (RTP):
| ReadyToProceed | Meaning |
| 0 | No |
| 1 | Yes |
Motor Speed Output (MSO1 and MSO0):
| MotorSpeed | Meaning | |
| MSO1 | MSO0 | |
| 0 | 0 | Stop |
| 0 | 1 | Move Down |
| 1 | 0 | Move Up |
| 1 | 1 | undefined |
Door Control Output (DC):
| DoorControl | Meaning |
| 0 | Close the Doors |
| 1 | Open the Doors |
Timer Enable Output (DC):
| TimerEnable | Meaning |
| 0 | Reset the Timer |
| 1 | Allow the timer to count |
ELEC2042 2 of 4 2020 Session 2
Macquarie University Assignment 1 v1
Task
You are to design the state machine and combinatorial circuitry for the train control system. Your
state machine needs to keep track of the state of the doors, the state of the motor speed as well as
the if the train is at a station or not.
It is suggested, but not required, that the state is held in the following D flip flop groups:
State of Doors (Two flip flops)
Desired Motor Speed (Two flip flops)
Train Global State (Three flip flops)
The meanings of some of the bits in these flip flops may be as follows:
| State of Doors |
Meaning | |
| 0 | 0 | Doors Closed |
| 0 | 1 | Doors Opening |
| 1 | 0 | Doors Opened |
| 1 | 1 | Doors Closing |
| Desired Motor Speed |
Meaning | |
| 0 | 0 | Desired Stop |
| 0 | 1 | Desired Slow Adjust |
| 1 | 0 | Desired Medium Speed |
| 1 | 1 | Desired Full Speed |
| Train Global State | Meaning | |
| TGS0 | TGS1 | TGS2 |
| 0 | 0 | 0 |
| 0 | 0 | 1 |
| 0 | 1 | 0 |
| 0 | 1 | 1 |
| 1 | 0 | 0 |
| 1 | 0 | 1 |
| 1 | 1 | 0 |
| 1 | 1 | 1 |
ELEC2042 3 of 4 2020 Session 2
Macquarie University Assignment 1 v1
Questions
1. Create the state transition diagram for the entire system.
2. Assign TGS(0-3) State Values for each of the states defined.
3. Create truth tables for each of the D flip flop groups. You must include all necessary inputs
to allow you to specify the change in state for each group.
4. Create Karnaugh maps for each output (Flip flop) in the groups.
5. From the Karnaugh maps create minimum Sum-Of-Products equations for your state
machine. There should be one Sum-Of-Products equation for each D flip flop.
Submit your responses as a single typeset PDF file through the turnitin link on ilearn. Your
submission must be typeset, Karnaugh maps can be produced as Tables, or spreadsheet matrices.
Apart from the state transition diagram NO hand drawn or scanned input will be graded. Your
submission must include a faculty coversheet.
ELEC2042 4 of 4 2020 Session 2
Macquarie University Assignment 1 v1
