public class Pca9685 : I2CDevice
{
private readonly byte PCA9685_MODE1 = 0x00;
private readonly byte PCA9685_PRESCALE = 0xFE;
private readonly byte LED0_ON_L = 0x06;
private readonly byte LED0_ON_H = 0x07;
private readonly byte LED0_OFF_L = 0x08;
private readonly byte LED0_OFF_H = 0x09;
private readonly byte ALL_LED_ON_L = 0xFA;
private readonly byte ALL_LED_ON_H = 0xFB;
private int _period;
public Pca9685(int period) : base(new Configuration(0x40, 100))
{
this._period = period * 1000;
}
public void Reset()
{
this.Write(new byte[]{ PCA9685_MODE1, 0x00 });
Thread.Sleep(10);
}
internal void Start()
{
int hz = 1000000 / this._period;
this.Reset();
this.SetPwmFrequency(hz);
}
public void SetPwmFrequency(float frequency)
{
frequency *= 0.9f;
float prescaleval = 25000000;
prescaleval /= 4096;
prescaleval /= frequency;
prescaleval -= 1;
byte prescale = (byte)(prescaleval + 0.5);
byte[] buffer = new byte[1] { PCA9685_MODE1 };
if (this.Read(buffer) != 1)
{
throw new Exception("can not read mode1");
}
byte oldMode = buffer[0];
byte newMode = (byte)(((byte)oldMode & (byte)0x7F) | (byte)0x10);
// go to sleep
this.Write(new byte[] { PCA9685_MODE1, newMode });
this.Write(new byte[] { PCA9685_PRESCALE, prescale });
this.Write(new byte[] { PCA9685_MODE1, oldMode });
Thread.Sleep(5);
this.Write(new byte[] { PCA9685_MODE1, (byte)(oldMode | 0x80) });
byte[] bufferRead = new byte[] { PCA9685_MODE1 };
this.Read(bufferRead);
Debug.Print("Mode now: " + bufferRead[0].ToString());
}
internal void SetPwm(byte outputNumber, int on, int off)
{
Debug.Print("Output: " + outputNumber.ToString() + ", ON: " + on.ToString() + ", OFF: " + off.ToString());
byte targetOutput_ON_L = (byte)(LED0_ON_L + 4 * outputNumber);
byte targetOutput_ON_H = (byte)(LED0_ON_H + 4 * outputNumber);
byte targetOutput_OFF_L = (byte)(LED0_OFF_L + 4 * outputNumber);
byte targetOutput_OFF_H = (byte)(LED0_OFF_H + 4 * outputNumber);
this.Write(new byte[] { targetOutput_ON_L, (byte)on });
this.Write(new byte[] { targetOutput_ON_H, (byte)(on >> 8) });
this.Write(new byte[] { targetOutput_OFF_L, (byte)(off) });
this.Write(new byte[] { targetOutput_OFF_H, (byte)(off >> 8) });
}
private int Write(byte[] buffer)
{
I2CTransaction[] trans = new I2CTransaction[]
{
CreateWriteTransaction(buffer)
};
return Execute(trans, 1000);
}
private int Read(byte[] buffer)
{
I2CTransaction[] trans = new I2CTransaction[]
{
CreateReadTransaction(buffer)
};
return Execute(trans, 1000);
}
}
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