Lab$5$

Task $4$: Frequency Counter Displayed on LCD

Code

Type in the following code and get the frequency counter functional. Use signal generator $($ sq wave, $\backslash (5\backslash$mathrm$\{$~V$\},2\mathrm{.}5\backslash$mathrm$\{$v$\}\backslash )$ offet$)$ initially set to $1$ kHz to confirm operation.

The code uses an interrupt on pin $2$ to count pulses and displays the result on the LCD every second.

$\backslash$#include

$//$ Initialize the ICD object $($RS$,$ E$,$ D$4,$ D$5,$ D$6,$ D$7)$

$//$ Variables for frequency counting

volatile unsigned long pulsecount $\backslash (=0\backslash )$; $//$ Counts pulses on pin $2$

unsigned long frequency $\backslash (=\backslash$underline$\{\backslash$underline$\{$p i$\}\}//\backslash )$ Calculated frequency

void setup $()($

$//$ Set up the ICD

Lcsdubegind $\backslash ((16,2)$ ; $\backslash$quad $//\backslash )$ Initialize $16$x$2$ ICD

led.amint$("$Freq: $")$; $//$ Display static text

ladhastchas

$//$ Set up the frequency input pin

ginMode$(2,$ INPUT$)$;

$//$ Attach an interrupt to pin $2$ for frequency counting

$//$ Start serial conmunication $($optional$,$ for debugging$)$

Serial.begin $(9600)$

$//$ Display update interval $(1$ second$)$

delay$(1000)$;

$\backslash \}$

void $\backslash (\backslash$frac$\{1000()\}\{\backslash$text $\{$ I $\}\}\backslash )\backslash \{$

$//$ Disable interrupts to safely read pulse count

MeThaterpuputa$()$;

frequency $\backslash (=\backslash )$ pulseCount: $//$Copy pulse count to frequency variable

pulsecquat $\backslash (=\backslash$underline$\{\backslash$underline$\{0\}\}\backslash )//$ Reset pulse count for next second

interrupts $()$: $//$ Re$-$enable interrupts

$//$ Display frequency on LCD

dschasetcursage $(6,0)$; $//$ Move cursor to print frequency

led.print $("")$; $//$ Clear previous reading

lcd.drint$($frequency$)$: $//$ Print the frequency in Hz

$```$

$//$ Optional: print to Serial Monitor for debugging

Serial.wnkint$("$Frequency: $"$

Serial.print $($frequency$)$:

$```$

$```$

$//$ Delay for $1$ second before updating frequency again

delav$(1000)$;

$\}$

$//$ Interrupt Service Routine to count pulses

void count$\{$ulse$()\{$

pulaeckunt$++$; $//$ Increment pulse count on each interrupt

$\}$

$```$

Explanation of the Code

$1.$ Setup Function:

$-$ The LCD is initialized and displays "Freq: Hz $"$ as static text on the screen.

$-$ An interrupt is attached to pin $2,$ triggering the countFulse$()$ function on each rising edge, which increments the pulsecount variable.

$2.$ Loop Function:

$-$ Every second, the pulseCount $($measured in pulses per second$)$ is copied to frequency.

$-$ The pulseCount is reset to $0$ to start counting for the next interval.

$-$ The frequency is displayed on the LCD and optionally printed to the Serial Monitor.

$-$ The delav $(1000)$ creates a $1-$second interval between each frequency measurement.

$3.$ countPulse$()$ Interrupt Service Routine:

$-$ This function increments the gulsecount variable each time a rising edge is detected, allowing accurate frequency counting.