public void SetDesiredFrequency(double frequency)
{
frequency *= 0.9f; // Correct for overshoot in the frequency setting.
double prescaleval = 25000000;
prescaleval /= 4096;
prescaleval /= frequency;
prescaleval -= 1;
byte prescale = (byte)Math.Floor(prescaleval + 0.5f);
int oldMode = i2cDevice.ReadFromAddress((byte)PwmRegister.MODE1);
int newMode = (oldMode & 0x7f) | 0x10;
this.i2cDevice.WriteToAddress((byte)PwmRegister.MODE1, (byte)newMode);
this.i2cDevice.WriteToAddress((byte)PwmRegister.PRESCALE, (byte)prescale);
this.i2cDevice.WriteToAddress((byte)PwmRegister.MODE1, (byte)oldMode);
this.i2cDevice.WriteToAddress((byte)PwmRegister.MODE1, (byte)(oldMode | 0xa1));
}