PROJECT OPTION #$2$: ARITHMETIC CALCULATOR USING THE KEYPAD

Overview

Each student will be required to program his$/$her microcontroller to perform all four arithmetic operations $($add$,$ subtract, multiply and divide$)$ on two user$-$supplied operands and display that output to the LCD screen.

Detailed Specifications

The calculator will add, subtract, multiply and divide INTEGER numbers and show the result on the LCD screen. The user will utilize the keypad to enter the operands and select the operation according to the Calculator Operation section below.

Calculator Operation

Calculator operation will begin by displaying the text $"$NO $1"$ on the screen and wait for the user to use the keypad to type the first integer operand followed by pressing the $\text{'}$ #$\text{'}$ key. Ensure that the user input of the $1^{st}$ operand is mirrored on the screen. Also, signal an error to the user if non$-$integer value is entered by displaying the text "ERROR" and then restart step $1.$

Next, the text $"$NO $2"$ will display on the screen and the calculator will wait for the user to use the keypad to type the second integer followed by pressing the $\text{'}$#$\text{'}$ key. Ensure that the user input of the $2^{nd}$ operand is mirrored on the screen. Also, signal an error to the user if non$-$integer value is entered by displaying the text "ERROR" and then restart step $2.$

Upon the entry of the second operand, the calculator will display the text "SELECT OPERATION" on the screen. The keys A $-$ D are mapped to the four arithmetic operations as follows: A $-$ add, B $-$ subtract, C $-$ multiply, D $-$ divide. The calculator will wait for entry of the operator selection, which is signaled by entering one of the four letters and pressing the $\text{'}$#$\text{'}$ key. Ensure that the user input of the operation selected is mirrored on the screen. Also, signal an error to the user if the entry is not equal to $A-D$ by displaying the text "ERROR" and then restart step $3.$

After step $3,$ the calculator will display the operation result on the screen.

After step $4$ has been completed, calculator operation returns to step $1.$

Implementation Constraints

Each operation must be implemented using an assembly language$-$based function, that is$,$ a $.$asm file.

You must be able to enter multi$-$digit operands up to $4$ digits and display multi$-$digit results up to $6$ digits.