PWM frequency library

Development Libraries
190

Hi,

I have some problem with this library using an arduino mega:

I want to pilot 4 fans (classic pc pwm).

On my setup() i have:

InitTimersSafe();

tryF(2, frequency); // Front fan 1 t3B
tryF(3, frequency); // Front fan 2 t3C
tryF(5, frequency); // Front fan 3 t3A
tryF(6, frequency); // Front fan 4 t4A
  Serial.print("t3:");
  Serial.print(Timer3_GetFrequency());
  Serial.print("\nt4:");
  Serial.print(Timer4_GetFrequency());

tryF function:

void tryF(int8_t pin, int32_t freq)
{ 
  //sets the frequency for the specified pin
  bool success = SetPinFrequencySafe(pin, freq);

  if (success) {
    set(pin, 0);
    Serial.print(pin);
    Serial.print("=>");
    Serial.print(freq);
    Serial.print(": SUCCESS\n");
  } else {
    Serial.print(pin);
    Serial.print("=>");
    Serial.print(freq);
    Serial.print(": FAIL\n");
  }
}

And then, i have a set function callable by serial

void set(uint8_t pin, uint16_t val)
{
  Serial.print("Applicating ");
  Serial.print(pin);
  Serial.print("/");
  Serial.print(val);
  Serial.print("\n");
  pwmWriteHR(pin, val);
}

At the begin of my soft i have:

mega: init...
mega: Applicating 2/0
mega: 2=>25000: SUCCESS
mega: Applicating 3/0
mega: 3=>25000: SUCCESS
mega: Applicating 5/0
mega: 5=>25000: SUCCESS
mega: Applicating 6/0
mega: 6=>25000: SUCCESS
mega: init done (pwm)
mega: t3:25000
mega: t4:25000

So everything is fine and i see my fan throttle down to 500 rpm (hall detection on pins 21 20 19 18).
If i call set(2, 65535), my fan 1 goes to max speed (~1600 rpm) and not the others.
RPM:1695,540,570,525
If i call set(5, 65535), my fan 3 goes to max speed (~1600 rpm).
RPM:1650,540,1605,510

My problem is when i use for example:
set(5, 32767), my rpm report is strange:
RPM:1050,555,1620,525 => fan 1 on pin 2 have it's speed reduced!

I don't know where is the bad behavior of my soft. can someone help me?

Electricaly, pins of the arduino are directly connected to the pwm of the fan. Ground / 12v is supplied by an ATX power supply.
Same supply powers the PC piloting the arduino, threw usb.
Possibly ground issue?

Complete code linked.

antec_arduino.ino (2.74 KB)