circuitjs arduino example output PWM sine

circuitjs

<cir f="1" ts="5.0000000000000004e-8" ic="124.26481670549957" cb="50" pb="50" vr="5" mts="5e-11">
  <ExtVoltage x="336 80 288 80" f="0" wf="1" fr="40" maxv="5" nm="pin 3"/>
  <ExtVoltage x="336 192 288 192" f="0" wf="1" fr="40" maxv="5" nm="pin 9"/>
  <LED x="336 80 384 80" f="2" mo="default-led" cr="1" cg="0" cb="0" mbc="0.01"/>
  <r x="384 80 432 80" f="0" r="1000"/>
  <g x="432 80 448 80" f="0"/>
  <r x="336 192 384 192" f="0" r="1000"/>
  <LED x="480 176 528 176" f="2" mo="default-led" cr="1" cg="0" cb="0" mbc="0.01"/>
  <c x="384 240 384 192" f="2" c="1.0000000000000001e-7" iv="0.001" sr="0" vd="-2.120788941832159"/>
  <g x="384 240 384 256" f="0"/>
  <a x="400 176 480 176" f="8" ma="15" mi="-15" ga="100000"/>
  <w x="400 192 384 192" f="0"/>
  <w x="400 160 400 128" f="0"/>
  <w x="400 128 480 128" f="0"/>
  <w x="480 128 480 176" f="0"/>
  <r x="528 176 528 224" f="0" r="1000"/>
  <g x="528 224 528 240" f="0"/>
  <o en="13" sp="64" f="x2" p="0">
    <p v="0" sc="5"/>
    <p v="3" sc="0.00009765625"/>
  </o>
  <o en="1" sp="64" f="x200012" p="0">
    <p v="0" sc="5" ms="20" mp="0"/>
    <p v="3" sc="0.003125" ms="0.001" mp="0"/>
  </o>
</cir>

gistfile1.txt

#define PWM_PIN 9 // Must be a PWM pin (3, 5, 6, 9, 10, or 11)

// Sine lookup table (256 values, 1 cycle)
const byte sineTable[256] = {
  0x80, 0x83, 0x86, 0x89, 0x8C, 0x90, 0x93, 0x96,
  0x99, 0x9C, 0x9F, 0xA2, 0xA5, 0xA8, 0xAB, 0xAE,
  0xB1, 0xB3, 0xB6, 0xB9, 0xBC, 0xBF, 0xC1, 0xC4,
  0xC7, 0xC9, 0xCC, 0xCE, 0xD1, 0xD3, 0xD5, 0xD8,
  0xDA, 0xDC, 0xDE, 0xE0, 0xE2, 0xE4, 0xE6, 0xE8,
  0xEA, 0xEB, 0xED, 0xEF, 0xF0, 0xF1, 0xF3, 0xF4,
  0xF5, 0xF6, 0xF8, 0xF9, 0xFA, 0xFA, 0xFB, 0xFC,
  0xFD, 0xFD, 0xFE, 0xFE, 0xFE, 0xFF, 0xFF, 0xFF,
  0xFF, 0xFF, 0xFF, 0xFF, 0xFE, 0xFE, 0xFE, 0xFD,
  0xFD, 0xFC, 0xFB, 0xFA, 0xFA, 0xF9, 0xF8, 0xF6,
  0xF5, 0xF4, 0xF3, 0xF1, 0xF0, 0xEF, 0xED, 0xEB,
  0xEA, 0xE8, 0xE6, 0xE4, 0xE2, 0xE0, 0xDE, 0xDC,
  0xDA, 0xD8, 0xD5, 0xD3, 0xD1, 0xCE, 0xCC, 0xC9,
  0xC7, 0xC4, 0xC1, 0xBF, 0xBC, 0xB9, 0xB6, 0xB3,
  0xB1, 0xAE, 0xAB, 0xA8, 0xA5, 0xA2, 0x9F, 0x9C,
  0x99, 0x96, 0x93, 0x90, 0x8C, 0x89, 0x86, 0x83,
  0x80, 0x7D, 0x7A, 0x77, 0x74, 0x70, 0x6D, 0x6A,
  0x67, 0x64, 0x61, 0x5E, 0x5B, 0x58, 0x55, 0x52,
  0x4F, 0x4D, 0x4A, 0x47, 0x44, 0x41, 0x3F, 0x3C,
  0x39, 0x37, 0x34, 0x32, 0x2F, 0x2D, 0x2B, 0x28,
  0x26, 0x24, 0x22, 0x20, 0x1E, 0x1C, 0x1A, 0x18,
  0x16, 0x15, 0x13, 0x11, 0x10, 0x0F, 0x0D, 0x0C,
  0x0B, 0x0A, 0x08, 0x07, 0x06, 0x06, 0x05, 0x04,
  0x03, 0x03, 0x02, 0x02, 0x02, 0x01, 0x01, 0x01,
  0x01, 0x01, 0x01, 0x01, 0x02, 0x02, 0x02, 0x03,
  0x03, 0x04, 0x05, 0x06, 0x06, 0x07, 0x08, 0x0A,
  0x0B, 0x0C, 0x0D, 0x0F, 0x10, 0x11, 0x13, 0x15,
  0x16, 0x18, 0x1A, 0x1C, 0x1E, 0x20, 0x22, 0x24,
  0x26, 0x28, 0x2B, 0x2D, 0x2F, 0x32, 0x34, 0x37,
  0x39, 0x3C, 0x3F, 0x41, 0x44, 0x47, 0x4A, 0x4D,
  0x4F, 0x52, 0x55, 0x58, 0x5B, 0x5E, 0x61, 0x64,
  0x67, 0x6A, 0x6D, 0x70, 0x74, 0x77, 0x7A, 0x7D
};

int stepIndex = 0;

void setup() {
  pinMode(PWM_PIN, OUTPUT);

  noInterrupts();
  
  // Set Timer 1 (Pins 9 and 10) to fastest PWM frequency 
  TCCR1B = (TCCR1B & 0xF8) | 0x01;
}

void loop() {

  while ((TIFR1 & (1 << TOV1)) == 0) {
    // Wait here until the overflow flag (TOV1) is set by the hardware
  }  
  // Clear the flag by writing a 1 to it
  TIFR1 |= (1 << TOV1);

  // Read the current duty cycle value from the lookup table
  analogWrite(PWM_PIN, sineTable[stepIndex]);
  
  // Advance to the next step
  stepIndex = ((stepIndex + 1) & 255);
}