$//$ Hardware: One button with GPIO pullup resistor.

$//$ One Green LED with $330$ Ohm resistors.

$//$ One Red LED with $330$ Ohm resistors.

$//$

The LCD with variable resistor to control brightness of backlight

$//$

$//$

$//$ Problem Statement: Build an Arduino project that uses the LCD. Setup the LCD according to Lab$-4.$

$//$ Setup a push$-$button on digital pin$-7.$ Configure analog pin A$0$ as a digital output pin for

$//$ Green LED. Configure analog pin A$1$ as a digital output pin for Red LED.

$//$

$//$ Create a global constant char variable for a letter, use first letter of first name.

$//$ Create two global unsigned int variables, one for LCD row $($row$),$ one for LCD column $($col$)$

$//$

$//$ When program $($loop function$)$ starts, it will be trapped in a while loop, until

$//$ the push$-$button is pushed. Inside trap while loop, clear LCD and set both LEDs Off.

$//$

$//$ After exit trap while loop, set row $=0.$ Turn On Green LED. Turn Off Red LED.

$//$

$//$ Enter for loop, initialize column to zero, loop until column number $>15.$ Inside for loop:

$//$ clear LCD, Set cursor position to current Column, row position, Print char letter to LCD,

$//$ delay $0\mathrm{.}5$ seconds, end for loop

$//$

$//$ After exit for loop, set row $=1.$ Turn Off Green LED. Turn On Red LED.

$//$

$//$

$//$

$//$ Enter another for loop, initialize column to zero, loop until column number $>15.$ Inside for loop:

$//$ clear LCD, Set cursor position to current Column, row position, Print char letter to LCD,

$//$ delay $0\mathrm{.}5$ seconds, end for loop

$//$ End loop function

$//$

$//$

$//****$ Pseudocode Algorithm $****$

$//$

$//$

$//$ include LiquidCrystal.h $($header file $-$ show program where LCD functions are and where located$)$

$//$

$//$ call LiquidCrystal LCD function to setup LCD pins

$//$

$//$ Global Constants: $($can not change value during program execution $-$ constant$)$

$//$ const char letter $=\text{'}$L$\text{'}$; $//$ char $\text{'}$L$\text{'}$ from Leslie

$//$

$//$

$//$ Global Variables: $($can change value any time in program $-$ variable$)$

$//$ unsigned int row $=0$; $//$ start row zero, top row

$//$ unsigned int col $=0$; $//$ start column zero, left column

$//$

$//$

$//$ setup$()$

$//$

$//$ call LCD begin function, configure as $16$ columns by $2$ rows LCD

$//$ call LCD clear function, clear LCD

$//$

$//$ set digital pin $7$ as input pullup

$//$ set analog input pin A$0$ as digital output, Green LED

$//$ set analog input pin A$1$ as digital output, Red LED

$//$

$//$ end setup function

$//$

$//$

$//$ loop$()$

$//$

$//$ while digitalRead $==$ high $($do nothing while button not pushed$)$

$//$ clear LCD

$//$ turn Off Green LED

$//$ turn Off Red LED

$//$ end trap while loop

$//$

$//$

$//$ row $=0($top LCD row$)$

$//$ turn On Green LED

$//$ turn Off Red LED

$//$

$//$

$//$ for loop, col $=0,$ col $<16,$ col$++$

$//$ clear LCD

$//$ set cursor position to col, row

$//$ print char letter

$//$ delay $0\mathrm{.}5$ sec

$//$ end for loop

$//$

$//$

$//$ row $=1$

$//$ turn Off Green LED

$//$ Turn On Red LED

$//$

$//$

$//$ for loop, col $=0,$ col $<16,$ col$++$

$//$ clear LCD

$//$ set cursor position to col, row

$//$ print char letter

$//$ delay $0\mathrm{.}5$ sec

$//$ end for loop

$//$

$//$ end loop