Question:

PWM or CTC modes can be used to create a 50% duty cycle wave. In the below, I used CTC mode to create square waves with frequencies of musical notes. Now I am going to revisit that design challenge using PWM. Think about how the two modes differ in the waveforms they create. In CTC mode I only had to change the compare register to change the period. In PWM mode you have to change 1 register to change the period and another register to change the pulsewidth to maintain 50% duty cycle. Rewrite the below code using PWM mode.

REFRENCES

Below is the code done before:

#define LA 36364

#define LAS 34335

#define LB 32389

#define LC 30534

#define LCS 28881

#define LD 27211

#define LDS 25723

#define LE 24242

#define LF 22923

#define LFS 21622

#define LG 20408

#define LGS 19277

#define MA 18182

#define MAS 17167

#define MB 16194

#define MC 15296

#define MCS 14440

#define MD 13629

#define MDS 12862

#define ME 12140

#define MF 11461

#define MFS 10811

#define MG 10204

#define MGS 9627

#define HA 9091

#define WHOLE 1000

#define DHALF 750

#define HALF 500

#define QUARTER 250

void setup() {

DDRD = 0x01;

TCCR1A = 0;

TCCR1B = 0;

TCNT1 = 0;

TCCR1A |= (1

TCCR1B |= (1

}

void loop() {

playNote(LDS, WHOLE);

}

void playNote(int note, int timeNote) {

TCCR1B |= (1

OCR1A = note;

delay(timeNote);

TCCR1B |= (0

delay(50);

The image depicts what the code is all about:

1. Given 25 notes of the musical scale below: LA LAS LB LC LCS LD LDS LE LF LFS LG LGS MA MAS MB MC MCS MD MDS ME MF MFS MG MGS HA They are each produced by a square wave with frequency as defined by the following formula P/12 note 440* 2 re P ranges from -12 (low A - LA) to 12 (high A - HA) The period of the square wave is illustrated in figure 1 below inote -- note 2 2 fnote note Figure 1: Equations for Period and h Period of a note square wave 16MHz Clock cycle in /2 Tnote- 2note 16MHz-2note = (OCRIA + 1) For the 25 notes (fnote- 220 through fnote -880) determine the OCR1A values needed to output the square wave of each note using Timer1 in CTC mode. Hint: write a program to do the math for vou and print the results to the serial monitor