/// <summary>
/// Performs the necessary activities to construct an XBee packet from the frame data.
/// This includes: computing the checksum, escaping the necessary bytes, adding the start byte and length bytes.
/// The format of a packet is as follows:
/// start byte - msb length byte - lsb length byte - frame data - checksum byte
/// </summary>
/// <param name="request"></param>
public static byte[] GetBytes(XBeeRequest request)
{
var frameData = request.GetFrameData();
// packet size is frame data + start byte + 2 length bytes + checksum byte
var bytes = new byte[frameData.Length + 4];
bytes[0] = (byte)SpecialByte.StartByte;
// Packet length does not include escape bytes or start, length and checksum bytes
var length = (ushort)frameData.Length;
// msb length (will be zero until maybe someday when > 255 bytes packets are supported)
bytes[1] = UshortUtils.Msb(length);
// lsb length
bytes[2] = UshortUtils.Lsb(length);
Array.Copy(frameData, 0, bytes, 3, frameData.Length);
// set last byte as checksum
// note: if checksum is not correct, XBee won't send out packet or return error. ask me how I know.
bytes[bytes.Length - 1] = Checksum.Compute(frameData, 0, frameData.Length);
var preEscapeLength = bytes.Length;
// TODO save escaping for the serial out method. this is an unnecessary operation
bytes = EscapePacket(bytes);
var escapeLength = bytes.Length;
var packetStr = "Packet: ";
for (var i = 0; i < escapeLength; i++)
{
packetStr += ByteUtils.ToBase16(bytes[i]);
if (i < escapeLength - 1)
{
packetStr += " ";
}
}
Logger.LowDebug(packetStr);
Logger.LowDebug("pre-escape packet size is " + preEscapeLength + ", post-escape packet size is " + escapeLength);
return(bytes);
}
/// <summary>
/// If digital I/O line (DIO0) is enabled: returns true if digital 0 is HIGH (ON); false if it is LOW (OFF).
/// If digital I/O line is not enabled this method returns false.
/// </summary>
/// <remarks>
/// Important: the pin number corresponds to the logical pin (e.g. D4), not the physical pin number.
/// Digital I/O pins seem to report high when open circuit (unconnected)
/// </remarks>
/// <param name="pin"></param>
/// <returns></returns>
public bool IsDigitalOn(Pin pin)
{
if (!IsDigitalEnabled(pin))
{
return(false);
}
var pinNumber = (byte)pin;
if (pinNumber >= 0 && pinNumber <= 7)
{
return(ByteUtils.GetBit(UshortUtils.Lsb(Digital), pinNumber));
}
return(ByteUtils.GetBit(UshortUtils.Msb(Digital), pinNumber - 8));
}
public bool IsDigitalEnabled(Pin pin)
{
var pinNumber = (byte)pin;
if (pinNumber >= 0 && pinNumber <= 7)
{
return(ByteUtils.GetBit(UshortUtils.Lsb(DigitalChannelMask), pinNumber));
}
if (pinNumber >= 10 && pinNumber <= 12)
{
return(ByteUtils.GetBit(UshortUtils.Msb(DigitalChannelMask), pinNumber - 8));
}
throw new ArgumentOutOfRangeException("Unsupported pin: " + pin);
}
