# Project 6, Exercise 2

## Overview

This Exercise is based on the material covered in Real Digital Project 6, which can be found in the red tab to the right. A downloadable document for this exercise is available in the orange tab to the right. The mention of grading within the downloadable document is due to the exercise material being used as course work for an electrical engineering class at a university.

##### Before beginning this project, you shouldâ€¦
• Be able to specify, design, and minimuze combinational logic systems.
• Be able to create schematic-based or VHDL-based designs in the Xilinx® WebPACK™ environment.
• Be able to download design created in WebPACK to the Digilent Circuit Board.
##### After completing this project, you shouldâ€¦
• Understand the application, function, and structure of decoder, multiplexor, encoder, and shifter circuits.
• Know how to use these circuits in the solution of larger problems.
• Be able to implement any given combinational circuit using the Xilinx CAD tool environment.
##### This project requires:
• A windows computer running Xilinx WebPACK.
• A Digilent board.

#### Problem 1.

Create a VHDL source file for a circuit that behaves according to the requirements shown by the K-map below. Simulate the circuit using a VHDL test bench, and print and submit the VHDL source files and the simulation output.

#### Problem 2.

Design and implement mux/de-mux circuit using the Xilinx® Tools and the Digilent board that can communicate 8 data signals using only 4 wires. Use three slide switch inputs to select the data channel, four buttons to form the eight required data channel inputs, and 8 LEDs to show the output. The eight inputs are formed from the four buttons as follows: I0 = BTN1; I1 = BTN2; I2 = BTN3; I3 = BTN4; I4 = BTN1 and BTN2; I5 = BTN2 and BTN3; I6 = BTN3 and BTN4; and I7 = BTN4 and BTN1. After the circuit design is complete, simulate the circuit, and download it to the Digilent board.

#### Problem 3.

Design and implement mux/de-mux circuit using the Xilinx Tools and the Digilent board that can communicate 8 data signals using only 4 wires. Use three slide switch inputs to select the data channel, four buttons to form the eight required data channel inputs, and 8 LEDs to show the output. The eight inputs are formed from the four buttons as follows: I0 = BTN1; I1 = BTN2; I2 = BTN3; I3 = BTN4; I4 = BTN1 and BTN2; I5 = BTN2 and BTN3; I6 = BTN3 and BTN4; and I7 = BTN4 and BTN1. After the circuit design is complete, simulate the circuit and download it to the Digilent board.

#### Problem 4.

Use the Xilinx Tools to define and simulate a 8-3 priority encoder with Enable In, Enable Out, and Group Signal.

#### Problem 5.

Use the Xilinx tools to define and simulate an 8-bit shifter in VHDL that can shift or rotate left or right by 0, 1, 2, or 3 bit positions. Implement this circuit in the Digilent board, Use the 8 slide switches as inputs to the shifter, and 8 LEDs as outputs from the shifter. Use the pushbuttons to control the functions of the shifter.