Create traffic light controller with ROM and basic logic components

[sajjad.hussain]

The traffic light controller should have 4 states in total:

1. at start , the green traffic light and the red footwalker light is active
2. when pushbutton is pressed the yellow light of traffic lights becomes active and the red footwalker light still remains active while the timer starts for 3 seconds.
3. in next state, the traffic light turns to red while the footwalker light turns to green and another timer starts for 20 seconds.
4. in next state, after the timer expires the traffic light becomes yellow again and the footwalker light becomes red and the first timer runs again for 3 seconds. the program returns to its initial state after the completion.

The state can been seen here:

The circuit diagram implemented in profilab is shown in the image given below:

I have been trying since last week and i have successfully implemented 3 states in profilab expert4.0 but i am unable to execute the 4th state. if i implement the 4th state, the whole program stops working.

the content of the ROM for my working example (for only 3 states) is:

If someone helps me with this problem and guide me what should be the contect of the ROM for first 16 locations. Regards

 

[nand_gates]

Here it goes ....

 

[danadakk]

An alternative method -

Part 1

Part 2


Regards, Dana.

 

[dpaul]

@all,
The OP needs a solution with a particular software I have never heard of "profilab".