Controlling 4pin fan with PWM 25Khz

Using Arduino Programming Questions
12

Hi there,

I was wondering how would you actually use dlloyd's code to control the PWM? Wouldn't you need something like digitalWrite() somewhere in there to tell the Arduino to have a certain PWM value?

dlloyd:
Yes, 25kHz PWM is possible ...

word VentPin = 3;

void setup() {
 pinMode(VentPin, OUTPUT);
 pwm25kHzBegin();
}

void loop() {
 pwmDuty(19); // 25% (range = 0-79 = 1.25-100%)
 delay(5000);
 pwmDuty(39); // 50% (range = 0-79 = 1.25-100%)
 delay (5000);
 pwmDuty(59); // 75% (range = 0-79 = 1.25-100%)
 delay (5000);
}

void pwm25kHzBegin() {
 TCCR2A = 0;                               // TC2 Control Register A
 TCCR2B = 0;                               // TC2 Control Register B
 TIMSK2 = 0;                               // TC2 Interrupt Mask Register
 TIFR2 = 0;                                // TC2 Interrupt Flag Register
 TCCR2A |= (1 << COM2B1) | (1 << WGM21) | (1 << WGM20);  // OC2B cleared/set on match when up/down counting, fast PWM
 TCCR2B |= (1 << WGM22) | (1 << CS21);     // prescaler 8
 OCR2A = 79;                               // TOP overflow value (Hz)
 OCR2B = 0;
}

void pwmDuty(byte ocrb) {
 OCR2B = ocrb;                             // PWM Width (duty)
}

Thanks!