Digital Systems Lab 13

Lab 13: Traffic Light State Machine

Lab 13 will come from the published version of the lab manual.

Breaking Lab 13 Into Parts

You may not be able to finish this circuit if you do not have a solid plan for building the circuit. Here are the steps you should take to build the circuit.

  • First wire up the monostable timers with active LOW pushbuttons to ensure that they function correctly (use LEDs on the output pins).
  • Then build the FSM and put LEDs on the flip-flop outputs to ensure that the FSM cycles through each state properly (you should see the LEDs light up consistent with your state assignments).
  • Finally, include the synchronous output LEDs. Don’t remove any of the other diagnostic LEDs until you get everything working.
Other Tips
  • Use ~500 Hz clock
  • Keep notes of what’s connected to each logic gate
  • Use wire colors to stay organized
Lab Manual Errata

The following are known errors in the lab manual corresponding to this lab.

  • Page 168 part (d), k-maps are labeled AB/CD, but should be labeled LS/AB.
  • Page 169 part (e), k-maps are labeled AB/CD, but should be labeled LS/AB.
  • Page 171 should say “The asynchronous outputs are in form TL TS, …”
  • Page 176 part (c) should say “Use a K-map to determine state assignments. Indicate the binary values for each state. The reset state should have a binary assignment of all zeros.
Lab Modifications

The following parts of this lab have been modified from the published version of the lab manual.

  • none
Resources

Watch/read the following resources prior to attending this lab. This information will teach you how to use lab equipment and provide suggestions and technical tips for successfully completing the lab.