Two function calculator with special operations with xilinx ise 9.2 and digilent spartan 3e starter kit board

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Lab 14 – Tutorial
Two Function Calculator with Special Operations with Xilinx ISE 9.2 and Digilent Spartan 3E Starter Kit Board

-Introduction

At this time, the student should be ableto deal with sequence detectors, counters, seven segment displays and frequency dividers (among others). The two function calculator with special operations is a good laboratory to implement a systemcomposed of several of these components exploring new implementation alternatives using VHDL and the Digilent Spartan 3E Starter Kit Board resources.

-Objective

In this tutorial, the designerwill have to implement a two-function calculator with special operations. The calculator should accept two parallel-input numbers, A and B, (2 bits each) and multiplies them if the Operation inputequals ‘1’ or adds them if ‘0’. Then, the system has to count up cyclically from 0 to 99 in steps equals to the result of the operation synchronously with the system clock, displaying the result on atwo-digit display. The counter stops if the serial sequence “11101” is entered by a serial input rx, and restarts if a second sequence “11101” is detected.

-Process

1. Design a unit able to addand multiply two 2-bits numbers.
2. Design a serial receiver that identifies a specific sequence of bits.
3. Design a cyclic upward counter with a variable step size determined by adigital input.
4. Design a synchronous 7-segment display controller that shows the output of the upward counter.

-Implementation

1. The unit that will add and multiply two 2-bit numbersshould have a selector input named Operation that is type std_logic. When this input equals ‘0’ the unit adds the two 2-bit inputs, otherwise the system multiplies them. The following is a possible code toimplement such a unit:

EXAMPLE ADDER MULTIPLIER CODE

-- This entity behaves as an adder/multipler with 2 inputs circuit.
-- Every input has a lentgh of 2 bits
entity add_mult is...