Wish I need a wrapper for my I2C 1 to 16 servo board

Cableguy

Expert
Licensed User
It seems to work OK...

I'm just having trouble understanding the SetPin and SetPWM methods... I can't understand the logic behind the values
 

Michael1968

Active Member
Licensed User
hi Cableguy,

If i understand it right...

setPWM writes the values to the register of the pca9685
B4X:
void Adafruit_PWMServoDriver::setPWM(uint8_t num, uint16_t on, uint16_t off) {
  //Serial.print("Setting PWM "); Serial.print(num); Serial.print(": "); Serial.print(on); Serial.print("->"); Serial.println(off);

  WIRE.beginTransmission(_i2caddr);
  WIRE.write(LED0_ON_L+4*num);
  WIRE.write(on);
  WIRE.write(on>>8);
  WIRE.write(off);
  WIRE.write(off>>8);
  WIRE.endTransmission();
}
setpin set the values for the on/off registers for the given Channel
B4X:
void Adafruit_PWMServoDriver::setPin(uint8_t num, uint16_t val, bool invert)
{
  // Clamp value between 0 and 4095 inclusive.
  val = min(val, 4095);
  if (invert) {
    if (val == 0) {
      // Special value for signal fully on.
      setPWM(num, 4096, 0);
    }
    else if (val == 4095) {
      // Special value for signal fully off.
      setPWM(num, 0, 4096);
    }
    else {
      setPWM(num, 0, 4095-val);
    }
  }
  else {
    if (val == 4095) {
      // Special value for signal fully on.
      setPWM(num, 4096, 0);
    }
    else if (val == 0) {
      // Special value for signal fully off.
      setPWM(num, 0, 4096);
    }
    else {
      setPWM(num, 0, val);
    }
  }
}
Michael
 
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