PWM_Fan_Test

#include <Wire.h>
#include <Adafruit_PWMServoDriver.h>
#include <FreqPeriodCounter.h>

Adafruit_PWMServoDriver pwm = Adafruit_PWMServoDriver(0x40);

bool serialVerbose = false;
uint16_t setPoint[16]; // number of set points
uint16_t initsetPointVal = 512; // setPoint initialization value
float setPointRPM = 320.0;
float valueRPM = 0.0;
float counterPeriod = 0.0;
uint16_t pulsePerRev = 4; // May depend on fan motor design. Could be 3 for the 9 mm motors
int numReadings = 1;
#define maxReadings 1000
float readings[maxReadings];
uint16_t readIndex = 0;
float total = 0;
float average = 0;


/*
512  =  320 RPM
640  =  350 RPM
768  =  660 RPM
896  =  925 RPM
1024 = 1150 RPM
1152 = 1400 RPM
1280 = 1670 PRM
1408 = 1930 RPM
1536 = 2225 RPM
1664 = 2682 RPM ** probable top stir speed
2048 =  RPM
3072 =  7500 RPM ** Starting Speed **
*/

const byte counterPin = 5;
const byte counterInterrupt = 5; // not sure if this works with D5

FreqPeriodCounter counter(counterPin, micros, 0);

void setup() {
  SerialUSB.begin(115200);
  delay(1000);
  //while (!SerialUSB) {
  //  delay(1); // wait for serial port to connect. Needed for native USB port only
  //}
  SerialUSB.println("16 channel PWM test Plus Period Counter!");
  //*/

  pinMode(counterPin, PIO_EXTINT);
  attachInterrupt(counterInterrupt, counterISR, CHANGE);

  for (int thisReading = 0; thisReading < numReadings; thisReading++) {
    readings[thisReading] = 0;
  }

  pwm.begin();
  // pwm.setOscillatorFrequency(27000000);
  pwm.setPWMFreq(1000);  // This is the maximum PWM frequency
  // Wire.setClock(400000);

  // initialize setPoint array Values
  for (uint8_t pwmnum=0; pwmnum < 16; pwmnum++) {
      setPoint[pwmnum] = initsetPointVal;
  }
  // Set to zero for testing
  for (uint8_t pwmnum=0; pwmnum < 16; pwmnum++) {
      pwm.setPWM(pwmnum, 0, 0);
  }
  delay(5000);
  // Start Spinning
   startSequence(3072, initsetPointVal, 50);

}

void loop() {
  //delay(100);
  if(counter.ready()){//*/
    counterPeriod = counter.period;
    valueRPM = (1/((counterPeriod*pulsePerRev/1000)/1000))*60;
    SerialUSB.print(valueRPM, 1);
    total = total - readings[readIndex];
    readings[readIndex] = valueRPM;
    total = total + readings[readIndex];
    readIndex++;
    if (readIndex >= numReadings){
      readIndex = 0;
    }
    average = total/numReadings;
    SerialUSB.print("\t");
    SerialUSB.println(average, 1);

    if(serialVerbose){
    SerialUSB.print(counter.period);
    SerialUSB.print("\t");
    SerialUSB.print(counter.pulseWidth);
    SerialUSB.print("\t");
    SerialUSB.println(counter.pulseWidthLow);
    }
  }//*/

}

void startSequence(int startVal, int finalVal, int startDuration){
  for (uint8_t pwmnum=0; pwmnum < 16; pwmnum++) {
      pwm.setPWM(pwmnum, 0, startVal);
    }
  delay(startDuration);
  for (uint8_t pwmnum=0; pwmnum < 16; pwmnum++) {
      pwm.setPWM(pwmnum, 0, setPoint[pwmnum]);
    }
}

void counterISR(){
  counter.poll();
}