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);
}
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 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"));
}