/// <summary>
/// Creates an instance and reads current values.
/// </summary>
/// <remarks>
/// <para>
/// The required mode bits are set, but the device state and PWM values unchanged (supporting recovery).
/// Initializing without restart allows the caller decide whether to recover or reset the device.
/// Before starting any output be sure to check the <see cref="INavioPwmDevice.Frequency"/>.
/// </para>
/// <para>
/// To start with new settings, call <see cref="Reset"/> then set <see cref="Enabled"/>.
/// </para>
/// </remarks>
public Navio1LedPwmDevice()
{
try
{
// Initialize members
_pwmChannels = new PwmPulse[PwmChannelCount];
_pwmChannelsReadOnly = new ReadOnlyCollection <PwmPulse>(_pwmChannels);
// Connect to hardware
_device = new Pca9685Device(I2cControllerIndex, ChipNumber, ExternalClockSpeed);
_enablePin = GpioExtensions.Connect(GpioControllerIndex, OutputEnableGpioPin,
GpioPinDriveMode.Output, GpioSharingMode.Exclusive);
// Read properties
Read();
}
catch
{
// Close devices in case partially initialized
_device?.Dispose();
_enablePin?.Dispose();
// Continue error
throw;
}
}
/// <summary>
/// Sets a single channel value.
/// </summary>
void INavioPwmDevice.SetChannel(int number, PwmPulse value)
{
// Thread-safe lock
lock (_lock)
{
// Validate
if (number < 1 || number > PwmChannelCount)
{
throw new ArgumentOutOfRangeException(nameof(number));
}
var index = number - 1;
// Check frequency matches (no per-channel frequency on this device)
if (value.Frequency != _device.Frequency)
{
throw new ArgumentOutOfRangeException(nameof(value.Frequency));
}
// Do nothing when unchanged
var oldValue = _pwmChannels[index];
if (value == oldValue)
{
return;
}
// Write new value
_device.WriteChannelMs(PwmChannelIndex + index, value.Width);
// Update property
_pwmChannels[index] = value;
}
}
/// <summary>
/// Reads the PWM channels from the device then updates the related properties.
/// </summary>
void INavioPwmDevice.Read()
{
// Thread-safe lock
lock (_lock)
{
// Read channels together (BGR ordered)
var channels = _device.ReadChannels(PwmChannelIndex, PwmChannelCount);
// Update channel properties
var frequency = _device.Frequency;
for (int index = 0; index < PwmChannelCount; index++)
{
var widthTicks = channels[index].Width;
var widthMs = Pca9685ChannelValue.CalculateWidthMs(frequency, widthTicks);
_pwmChannels[index] = PwmPulse.FromWidth(frequency, widthMs);
}
}
}
/// <summary>
/// Reads the LED & PWM channels from the device then updates the related properties.
/// </summary>
public void Read()
{
// Thread-safe lock
lock (_lock)
{
// Read all PWM and LED channels
_device.ReadAll();
// Update LED properties
_ledRed = ~_device.Channels[LedRedChannelIndex].Width & 0xfff;
_ledGreen = ~_device.Channels[LedGreenChannelIndex].Width & 0xfff;
_ledBlue = ~_device.Channels[LedGreenChannelIndex].Width & 0xfff;
// Update PWM properties
var frequency = _device.Frequency;
for (int index = 0, pwmIndex = PwmChannelIndex; index < PwmChannelCount; index++, pwmIndex++)
{
var widthTicks = _device.Channels[pwmIndex].Width;
var widthMs = Pca9685ChannelValue.CalculateWidthMs(frequency, widthTicks);
_pwmChannels[index] = PwmPulse.FromWidth(frequency, widthMs);
}
}
}
