/// <summary>
/// Writes multiple channels together (both "on" and "off" values), 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="values">Collection of <see cref="Pca9685ChannelValue"/>s to write.</param>
public void WriteChannels(int index, IList <Pca9685ChannelValue> values)
{
// Validate
if (index <0 | index> ChannelCount)
{
throw new ArgumentOutOfRangeException(nameof(index));
}
if (values == null || values.Count == 0)
{
throw new ArgumentNullException(nameof(values));
}
var count = values.Count;
if (index + count > ChannelCount)
{
throw new ArgumentOutOfRangeException(nameof(values));
}
// Build I2C packet
var data = new byte[1 + ChannelSize * count];
// Calculate first register address
var register = GetChannelAddress(index);
data[0] = register;
// Write channels and update properties
for (int dataIndex = 0, dataOffset = 1; dataIndex < count; dataIndex++, dataOffset += ChannelSize)
{
// Get channel data
var channelData = values[dataIndex].ToByteArray();
// Copy to buffer
Array.ConstrainedCopy(channelData, 0, data, dataOffset, ChannelSize);
// Update property
_channels[index + dataIndex] = Pca9685ChannelValue.FromByteArray(channelData);
}
// Send packet
I2cExtensions.WriteBytes(_hardware, data);
}