/// <summary>
/// Writes the "on" and "off" values of a channel together, and updates it in <see cref="Channels"/>.
/// </summary>
/// <param name="index">Zero based channel number (0-15) or 16 for the "all call" channel.</param>
/// <param name="value"><see cref="Pca9685ChannelValue"/> to write.</param>
/// <returns>
/// Updated channel value or null when all channels were updated.
/// </returns>
public Pca9685ChannelValue?WriteChannel(int index, Pca9685ChannelValue value)
{
// Validate
if (index <0 | index> ChannelCount)
{
throw new ArgumentOutOfRangeException(nameof(index));
}
if (value == null)
{
throw new ArgumentNullException(nameof(value));
}
// Calculate register address
var register = GetChannelAddress(index);
// Convert and write value
var bytes = value.ToByteArray();
I2cExtensions.WriteJoinBytes(_hardware, register, bytes);
// Read and return result when single channel
if (index < ChannelCount)
{
return(ReadChannel(index));
}
// Read all channels when "all call".
ReadAllChannels();
return(null);
}
/// <summary>
/// Clears all channels cleanly, then updates all <see cref="Channels"/>.
/// </summary>
/// <remarks>
/// To "cleanly" clear the channels, it is necessary to first ensure they are not disabled,
/// set them to zero, then disable them. Otherwise the ON value and the low OFF value
/// remain because writes are ignored when the OFF channel bit 12 is already set.
/// </remarks>
public void Clear()
{
// Enable all channels
I2cExtensions.WriteJoinByte(_hardware, (byte)Pca9685Register.AllChannelsOffHigh, 0x00);
// Zero all channels
I2cExtensions.WriteJoinBytes(_hardware, (byte)Pca9685Register.AllChannelsOnLow, new byte[] { 0x00, 0x00, 0x00, 0x00 });
// Disable all channels
I2cExtensions.WriteJoinByte(_hardware, (byte)Pca9685Register.AllChannelsOffHigh, 0x10);
// Update channels
ReadAllChannels();
}
/// <summary>
/// Writes the PWM "off" (falling) value of a channel.
/// </summary>
/// <param name="index">Zero based channel number (0-15) or 16 for the "all call" channel.</param>
/// <param name="value">12-bit channel value in the range 0-<see cref="Pca9685ChannelValue.Maximum"/>.</param>
/// <exception cref="ArgumentOutOfRangeException">Thrown when the <paramref name="value"/> is greater then <see cref="Pca9685ChannelValue.Maximum"/>.</exception>
public void WriteChannelOff(int index, int value)
{
// Validate
if (value > Pca9685ChannelValue.Maximum)
{
throw new ArgumentOutOfRangeException(nameof(value));
}
// Calculate register address of second word value
var register = (byte)(GetChannelAddress(index) + sizeof(ushort));
// Convert and write value
var bytes = BitConverter.GetBytes(value);
I2cExtensions.WriteJoinBytes(_hardware, register, bytes);
}
/// <summary>
/// Writes the PWM "on" (rising) value of a channel.
/// </summary>
/// <param name="index">Zero based channel number (0-15) or 16 for the "all call" channel.</param>
/// <param name="value">12-bit channel value in the range 0-<see cref="Pca9685ChannelValue.Maximum"/>.</param>
/// <exception cref="ArgumentOutOfRangeException">Thrown when the <paramref name="value"/> is greater than <see cref="Pca9685ChannelValue.Maximum"/>.</exception>
public void WriteChannelOn(int index, int value)
{
// Validate
if (value > Pca9685ChannelValue.Maximum)
{
throw new ArgumentOutOfRangeException(nameof(value));
}
// Calculate register address
var register = GetChannelAddress(index);
// Convert and write value
var data = BitConverter.GetBytes(value);
I2cExtensions.WriteJoinBytes(_hardware, register, data);
}