/// <summary>
/// Reads the PWM "off" (falling) value of a channel, and updates it in <see cref="Channels"/>.
/// </summary>
/// <param name="index">Zero based channel number (0-15).</param>
/// <returns>Channel value.</returns>
public int ReadChannelOff(int index)
{
// Validate
if (index < 0 | index >= ChannelCount)
{
throw new ArgumentOutOfRangeException(nameof(index));
}
// Calculate register address of second word value
var register = (byte)(GetChannelAddress(index) + sizeof(ushort));
// Read and convert value
var bytes = I2cExtensions.WriteReadBytes(_hardware, register, sizeof(ushort));
var value = BitConverter.ToUInt16(bytes, 0);
// Update channel when changed
var oldValue = _channels[index];
if (oldValue.Off != value)
{
_channels[index] = new Pca9685ChannelValue(oldValue.On, value);
}
// Return result
return(value);
}
/// <summary>
/// Reads a coefficient value from the PROM.
/// </summary>
/// <param name="index">Coefficient index (0-7).</param>
/// <param name="buffer">Target buffer.</param>
/// <param name="offset">Target offset.</param>
/// <remarks>
/// Reads <see cref="Ms5611PromData.CoefficientSize"/> bytes into the target buffer at the specified offset.
/// </remarks>
private void ReadPromCoefficient(int index, byte[] buffer, int offset)
{
// Calculate address
var coefficientOffset = (byte)(index * Ms5611PromData.CoefficientSize);
var address = (byte)(Ms5611Command.PromRead + coefficientOffset);
// Read from hardware return value
var coefficient = I2cExtensions.WriteReadBytes(_hardware, address, Ms5611PromData.CoefficientSize);
Array.ConstrainedCopy(coefficient, 0, buffer, offset, Ms5611PromData.CoefficientSize);
}
/// <summary>
/// Reads all channels and updates <see cref="Channels"/>.
/// </summary>
public void ReadAllChannels()
{
// Read all channels as one block of data
var data = I2cExtensions.WriteReadBytes(_hardware, ChannelStartAddress, ChannelSize * ChannelCount);
// Update properties
for (var index = 0; index < ChannelCount; index++)
{
_channels[index] = Pca9685ChannelValue.FromByteArray(data, ChannelSize * index);
}
}
/// <summary>
/// Executes the <see cref="Ms5611Command.ConvertD2Temperature"/> command to measure
/// pressure at the specified OSR, waits then returns the result.
/// </summary>
public int ConvertTemperature(Ms5611Osr rate)
{
// Send command to hardware
I2cExtensions.WriteJoinByte(_hardware, (byte)(Ms5611Command.ConvertD2Temperature + (byte)rate), 0);
// Wait for completion
WaitForConversion(rate);
// Return result
var result = I2cExtensions.WriteReadBytes(_hardware, (byte)Ms5611Command.AdcRead, 3);
return(result[0] << 16 | result[1] << 8 | result[2]);
}
/// <summary>
/// Reads a whole channel value (on and off), and updates it in <see cref="Channels"/>.
/// </summary>
/// <param name="index">Zero based channel number (0-15).</param>
/// <returns>Channel value</returns>
public Pca9685ChannelValue ReadChannel(int index)
{
// Validate
if (index < 0 | index >= ChannelCount)
{
throw new ArgumentOutOfRangeException(nameof(index));
}
// Calculate register address
var register = GetChannelAddress(index);
// Read value
var bytes = I2cExtensions.WriteReadBytes(_hardware, register, sizeof(ushort) * 2);
// Update channel property and return result
var value = Pca9685ChannelValue.FromByteArray(bytes);
return(_channels[index] = value);
}
/// <summary>
/// Reads a "page" of bytes "sequentially" starting at the specified address.
/// </summary>
public byte[] ReadPage(int address, int length)
{
// Validate
if (address < 0 || address > Size - 1)
{
throw new ArgumentOutOfRangeException(nameof(address));
}
if (length < 0 || length > Size - address)
{
throw new ArgumentOutOfRangeException(nameof(length));
}
// Get correct I2C device and data for memory address and flags
var device = GetI2cDeviceForMemoryAddress(address);
// Read data with chunking when transfer size exceeds limit
var resultBuffer = new byte[length];
var remaining = length; var offset = 0;
do
{
var addressBytes = GetMemoryAddressBytes(address);
// Check transfer size and reduce when necessary
var transferSize = remaining;
if (transferSize > I2cExtensions.MaximumTransferSize)
{
transferSize = I2cExtensions.MaximumTransferSize;
}
// Read data
var buffer = I2cExtensions.WriteReadBytes(device, addressBytes, transferSize);
Array.ConstrainedCopy(buffer, 0, resultBuffer, offset, transferSize);
// Next transfer when necessary...
remaining -= transferSize;
offset += transferSize;
address += transferSize;
}while (remaining > 0);
return(resultBuffer);
}
/// <summary>
/// Reads multiple channel values (both on and off for each), and updates it in <see cref="Channels"/>.
/// </summary>
/// <param name="index">Zero based channel number (0-15).</param>
/// <param name="count">Number of channels to read.</param>
/// <returns>Channel values</returns>
public Collection <Pca9685ChannelValue> ReadChannels(int index, int count)
{
// Validate
if (index < 0 | index >= ChannelCount)
{
throw new ArgumentOutOfRangeException(nameof(index));
}
if (count < 1 || index + count > ChannelCount)
{
throw new ArgumentOutOfRangeException(nameof(count));
}
// Calculate register address
var register = GetChannelAddress(index);
// Send I2C command to read channels in one operation
var data = I2cExtensions.WriteReadBytes(_hardware, register, ChannelSize * count);
// Update channel properties and add to results
var results = new Collection <Pca9685ChannelValue>();
for (int channelIndex = index, offset = 0; count > 0; count--, channelIndex++, offset += ChannelSize)
{
// Calculate value
var value = Pca9685ChannelValue.FromByteArray(data, offset);
// Update property
_channels[channelIndex] = value;
// Add to results
results.Add(value);
}
// Return results
return(results);
}
