public static ushort Crc16Ccitt(string str)
{
byte[] bytes = NRF24Helpers.GetBytesFromHexString(str);
const ushort poly = 4129;
ushort[] table = new ushort[256];
ushort initialValue = 0xffff;
ushort temp, a;
ushort crc = initialValue;
for (int i = 0; i < table.Length; ++i)
{
temp = 0;
a = (ushort)(i << 8);
for (int j = 0; j < 8; ++j)
{
if (((temp ^ a) & 0x8000) != 0)
{
temp = (ushort)((temp << 1) ^ poly);
}
else
{
temp <<= 1;
}
a <<= 1;
}
table[i] = temp;
}
for (int i = 0; i < bytes.Length; ++i)
{
crc = (ushort)((crc << 8) ^ table[((crc >> 8) ^ (0xff & bytes[i]))]);
}
return(crc);
}
public static ushort TestCrc(string data, int test)
{
var combinedBitArray = NRF24Helpers.GetBitArrayFromHexString(data);
ushort testCrc = 0xFFFF;
for (var offsetFront = 0; offsetFront <= combinedBitArray.Length; offsetFront++)
{
for (var i = combinedBitArray.Length - offsetFront; i >= 0; i--)
{
//backwards stripping
var subBitArray = NRF24Helpers.GetPartOfBitArray(combinedBitArray, offsetFront, i);
testCrc = NRF24Helpers.GetCrc16(subBitArray);
if (testCrc == 0xB4CC && test == 1)
{
var b = "a";
}
if (testCrc == 0x52F7 && test == 2)
{
var b = "a";
}
if (testCrc == 0x354E && test == 3)
{
var b = "a";
}
}
}
return(testCrc);
}
private void UploadConfiguration(SerialPort serialPort)
{
var configuration = new byte[15];
configuration[0] = 0x4E; //lenAndType
configuration[1] = (byte)_generalSettings.RfChannel;
configuration[2] = (byte)_generalSettings.DataRate;
configuration[3] = (byte)_generalSettings.AddressLength;
configuration[4] = 0x04; //addressPromiscLen
var baseAddress = NRF24Helpers.GetBytesFromHexString(_generalSettings.BaseAddress);
configuration[5] = baseAddress[7];
configuration[6] = baseAddress[6];
configuration[7] = baseAddress[5];
configuration[8] = baseAddress[4];
configuration[9] = baseAddress[3];
configuration[10] = baseAddress[2];
configuration[11] = baseAddress[1];
configuration[12] = baseAddress[0];
configuration[13] = (byte)_generalSettings.CrcLength;
configuration[14] = (byte)_generalSettings.MaximumPayloadSize;
serialPort.BaseStream.Write(configuration, 0, configuration.Length);
}
public static string GetHexStringFromBitArray(BitArray bitArray)
{
if (bitArray.Length != 8)
{
return(string.Empty);
}
var b = NRF24Helpers.GetByteFromBitArray(bitArray, 0);
return(b.ToString("X2"));
}
private NRF24Data CreateNRF24Data(NRF24Structure nrf24Structure)
{
if (nrf24Structure.NRF24Header == null || nrf24Structure.Data.Length < 5)
{
return(null);
}
// Set the NRF24 data part
var nrf24Data = new NRF24Data
{
NodeAddress = $"{nrf24Structure.NRF24Header.Address}{nrf24Structure.Data.Substring(0, 2)}"
};
var controlFieldString = nrf24Structure.Data.Substring(2, 4);
var controlFieldBitArray = NRF24Helpers.GetBitArrayFromHexString(controlFieldString);
nrf24Data.PayloadLength = NRF24Helpers.GetPartOfBitArray(controlFieldBitArray, 0, 6);
nrf24Data.Pid = NRF24Helpers.GetPartOfBitArray(controlFieldBitArray, 6, 2);
nrf24Data.NoAck = controlFieldBitArray[9];
nrf24Data.Payload = nrf24Structure.Data.Substring(4, nrf24Structure.Data.Length - 4);
var payloadFieldBitArray = NRF24Helpers.GetBitArrayFromHexString(nrf24Data.Payload);
// For last byte only the MSbit has value; rest will be cleared
payloadFieldBitArray = NRF24Helpers.GetPartOfBitArray(payloadFieldBitArray, 0, payloadFieldBitArray.Length - 7);
// Get the packet crc (the crc is located in last two bytes of the packet)
var crcOffset = payloadFieldBitArray.Length - 16;
nrf24Data.PacketCrc = NRF24Helpers.GetPartOfBitArray(payloadFieldBitArray, crcOffset, 16);
// Remove the crc bits from the bitarray before it is processed further
nrf24Data.PayloadBitArray = NRF24Helpers.GetPartOfBitArray(payloadFieldBitArray, 0, payloadFieldBitArray.Length - 16);
//TODO what about the string payload??
// ****
// Calculate the crc ourselfs
// Get the payload in bits, as the bitArray is already stripped of all unneeded stuff, the length is the amount of bits
//var payloadLengthBits = payloadFieldBitArray.Length;
//var packetLengthBits = 40 + 9 + payloadLengthBits;
// As the crc is calculated over the address, packet control field and payload, attach the two fields
//var combinedString = $"{this.NRF24Header.Address}{this.Data}";
//var combinedString = $"{this.Data}";
// Create the NRF24Mysensor part
nrf24Data.NRF24Mysensor = CreateNRF24Mysensor(nrf24Data);
return(nrf24Data);
}
public static byte[] GetBytesFromBitArray(BitArray bitArray)
{
if (bitArray.Length % 8 != 0)
{
return(new byte[0]);
}
var count = bitArray.Length / 8;
var bytes = new byte[count];
for (var i = 0; i < count; i++)
{
bytes[i] = NRF24Helpers.GetByteFromBitArray(bitArray, i * 8);
}
return(bytes);
}
public static ushort GetCrc16(BitArray bitArray)
{
ushort crc = 0xFFFF;
ushort data;
byte workingByte;
int shift;
ushort bitoffs = 0;
workingByte = NRF24Helpers.GetByteFromBitArray(bitArray, bitoffs >> 3);
while (bitoffs < bitArray.Length)
{
shift = bitoffs & 7;
// Shift the active bit to the position of bit 15
data = (ushort)(workingByte << (8 + shift));
// Assure all other bits are 0
data &= 0x8000;
crc ^= data;
if ((crc & 0x8000) > 0)
//if ((crc & 0x8000) != 0)
//if ((crc & 0x8000) == 0)
{
crc = (ushort)((crc << 1) ^ 0x8408); // 0x1021 = (1) 0001 0000 0010 0001 = x^16+x^12+x^5+1
}
else
{
crc = (ushort)(crc << 1);
//crc <<= 1;
}
++bitoffs;
if (0 == (bitoffs & 7))
{
// Get a new byte for the next 8 bits.
workingByte = NRF24Helpers.GetByteFromBitArray(bitArray, bitoffs >> 3);
}
}
return(crc);
}
public static BitArray GetBitArrayFromHexString(string str)
{
// Get a list of hex values from the input string
var strings = NRF24Helpers.GetSplittedParts(str, 2);
// Create a new bitarray
var bitArray = new BitArray(strings.Count * 8);
var count = 0;
foreach (var chunk in strings)
{
var byteValue = Convert.ToByte(chunk, 16);
var array = new BitArray(new byte[] { byteValue });
for (var i = 7; i >= 0; i--)
{
bitArray[count++] = array[i];
}
}
return(bitArray);
}
public static string CalcCRC16(string strInput)
{
ushort crc = 0xFFFF;
byte[] data = NRF24Helpers.GetBytesFromHexString(strInput);
for (int i = 0; i < data.Length; i++)
{
crc ^= (ushort)(data[i] << 8);
for (int j = 0; j < 8; j++)
{
if ((crc & 0x8000) > 0)
{
crc = (ushort)((crc << 1) ^ 0x1021);
}
else
{
crc <<= 1;
}
}
}
return(crc.ToString("X4"));
}
private NRF24Mysensor CreateNRF24Mysensor(NRF24Data nrf24Data)
{
// Check if the bitArray contains enough information to be processed
if (nrf24Data.PayloadBitArray.Length < 57)
{
return(null);
}
// We should start at 1 as the string is not byte aligned
var bitOffset = 1;
// Set the MySensors data part
var nrf24Mysensor = new NRF24Mysensor();
nrf24Mysensor.Last = NRF24Helpers.GetByteFromBitArray(nrf24Data.PayloadBitArray, bitOffset);
bitOffset += 8;
nrf24Mysensor.Sender = NRF24Helpers.GetByteFromBitArray(nrf24Data.PayloadBitArray, bitOffset);
bitOffset += 8;
nrf24Mysensor.Destination = NRF24Helpers.GetByteFromBitArray(nrf24Data.PayloadBitArray,
bitOffset);
bitOffset += 8;
nrf24Mysensor.Length = NRF24Helpers.GetPartOfBitArray(nrf24Data.PayloadBitArray, bitOffset, 5);
bitOffset += 5;
nrf24Mysensor.Version = NRF24Helpers.GetPartOfBitArray(nrf24Data.PayloadBitArray, bitOffset, 3);
bitOffset += 3;
nrf24Mysensor.DataType = NRF24Helpers.GetPartOfBitArray(nrf24Data.PayloadBitArray, bitOffset, 3);
bitOffset += 3;
nrf24Mysensor.IsAck = nrf24Data.PayloadBitArray[bitOffset];
bitOffset++;
nrf24Mysensor.ReqAck = nrf24Data.PayloadBitArray[bitOffset];
bitOffset++;
nrf24Mysensor.CommandType = NRF24Helpers.GetPartOfBitArray(nrf24Data.PayloadBitArray, bitOffset, 3);
bitOffset += 3;
nrf24Mysensor.Type = NRF24Helpers.GetByteFromBitArray(nrf24Data.PayloadBitArray, bitOffset);
bitOffset += 8;
nrf24Mysensor.Sensor = NRF24Helpers.GetByteFromBitArray(nrf24Data.PayloadBitArray, bitOffset);
bitOffset += 8;
nrf24Mysensor.PayloadBitArray = NRF24Helpers.GetPartOfBitArray(
nrf24Data.PayloadBitArray,
bitOffset,
nrf24Data.PayloadBitArray.Length - bitOffset);
// Find, is enabled, the VeraDevices corresponding to the package
if (_generalSettings.LookupMysensorsNodeViaVera)
{
// Check if it is the gateway that sends the message
if (nrf24Mysensor.Sender == 0)
{
nrf24Mysensor.SenderVeraDevice = _veraSettings.VeraDevices
.SingleOrDefault(a_item => a_item.IsGateway);
}
else
{
nrf24Mysensor.SenderVeraDevice = _veraSettings.VeraDevices
.SingleOrDefault(
a_item => a_item.VeraDeviceAltID != null &&
a_item.VeraDeviceAltID.NodeID == nrf24Mysensor.Sender &&
a_item.VeraDeviceAltID.ChildID == 255);
}
// Check if it is the gateway that receives the message
if (nrf24Mysensor.Destination == 0)
{
nrf24Mysensor.DestinationVeraDevice = _veraSettings.VeraDevices
.SingleOrDefault(a_item => a_item.IsGateway);
}
else
{
nrf24Mysensor.DestinationVeraDevice = _veraSettings.VeraDevices
.Where(a_item => a_item.VeraDeviceAltID != null)
.SingleOrDefault(a_item =>
a_item.VeraDeviceAltID.NodeID == nrf24Mysensor.Destination &&
a_item.VeraDeviceAltID.ChildID == 255);
}
nrf24Mysensor.SensorVeraDevice = _veraSettings.VeraDevices
.Where(a_item => a_item.VeraDeviceAltID != null)
.SingleOrDefault(
a_item => a_item.VeraDeviceAltID.NodeID == nrf24Mysensor.Sender &&
a_item.VeraDeviceAltID.ChildID == nrf24Mysensor.Sensor);
}
return(nrf24Mysensor);
}
