CSE370 Laboratory Assignment 3

Constructing Simple Logic Circuits

Distributed: January 17, 2005
Due: Thursday (January 20, 2005) at 5pm

Objectives

Refer back to Tutorial #1 for help with Aldec Active-HDL 6.2

Tasks

1. Realize two circuits to detect a Fibonacci number between 1 and 15 (1, 2, 3, 5, 8, 13). One circuit should consider the number "0" a don't care value while the second circuit should be completed without don't cares (i.e. the number zero should be considered false). Make sure to minimize each circuit by using K-maps. NOTE: You will need to wire up BOTH circuits at the same time on your prototyping board so you should be careful with your gate choice when realizing your circuits. Keep this in mind as you may have to change the gates you use as you will be required to use ONLY the gates in your prototyping kit and you only have 1 chip for each gate type with the exception of an inverter chip which you should have two. Link to chips in your kit
2. Create a schematic in Active-HDL that includes both of your Fibonacci number detection circuits. Connect the outputs of both your circuits to a XOR gate to detect when the circuits behave differently. Make sure to verify that you have enough gates in your prototyping kit when making the schematic so you can wire up the identical circuit. NOTE: The gates in your Active-HDL solution must exactly match the gates used in your prototyping board solution.
3. Simulate both of your Fibonacci number detection circuits using the same technique as in the tutorial #1.  Create stimulators for the inputs A, B, C, and D with D changing every 20 time units, C every 40, B every 80, and A every 160.  Make sure to run your simulation long enough so that the inputs take on all possible combinations.  Your simulation results should clearly show that the output of the function is only true when the inputs correspond to a Fibonacci number (1, 2, 3, 5, 8, or 13). Your waveform should display 7 items: the 4 inputs (A, B, C, D),  the output from your XOR gate, and the two "wire/nets" (with_dont_cares/without_dont_cares) that connect each detection circuit to the XOR gate. Please refer to tutorial #1 to review how to name "wires/nets" or setup simulation stimuli. Follow the print instructions to print both your schematic and waveform on letter paper.
4. Using the schematic from task 2, construct both of your circuits that will identify a "Fibonacci Number" on the prototyping board by connecting the inputs to switches and the output of the XOR to an LED. In addition connect the results of the two detection circuits to LEDs. You will need 4 switches and 3 LEDs for this part. Please use: SW1 through SW4 for number value, LED1 for the XOR result, LED2 for the without don't cares result, and LED 3 for the with don't cares result. Demonstrate your circuit to a TA and have them check you off as having completed this laboratory assignment. They may ask you to show them your work and explain your circuit. HINT: If you circuit is not working as expected use the logic probe to trace through the circuit to help you identify any wiring errors