private void OnMessageReceived(ActisenseMessage msg)
{
if (!msg.CRCisOK)
{
if (BadCRCMessageReceived != null)
{
BadCRCMessageReceived(msg);
}
return;
}
if (ValidMessageReceived != null)
{
ValidMessageReceived(msg);
}
switch (msg.MessageType)
{
case N2kDataReceived:
var e = N2kMessageReceived;
if (e != null)
{
e(msg);
}
break;
default:
// TODO: This is some other Actisense message, eg a status message. Process it somehow...
break;
}
}
// Private methods
private void ProcessN2kMessage(ActisenseMessage msg)
{
/* This N2kDataReceived message goes:
* [0] Priority
* [1] PGN LSB=Least Significant Byte
* [2] PGN Middle Byte
* [3] PGN MSB=MostSignificant Byte
* [4] Destination
* [5] Source
* [6,7,8,9] Time stamp, LSB...MSB
* [10] N2k payload length
* [11, 12, ...] N2k payload (always 8 bytes in data seen so far)
*/
byte[] payload = msg.MessagePayload;
byte Priority = payload[0];
int PGN = payload[1] + (payload[2] << 8) + (payload[3] << 16);
byte Destination = payload[4];
byte Source = payload[5];
uint ms = BitConverter.ToUInt32(payload, 6);
// TODO: Work out what the Actisense is transmitting in its time-stamp field
// as the number of milliseconds appears to go down as well as up (according to a user report)
// Note that the Actisense clock appears to be reset when the unit is reset by software,
/* as indicated by the following R(read)/W(rite) sequence of commands
* Clock 4 bytes
* W: 10 2 A1 1 13 4B 10 3
* R: 10 2 93 13 2 2 FD 1 FF 3A 66 9F 0 0 8 FF 3 3 69 0 FA FF FF AC 10 3
* R: 10 2 A0 0E 13 1 0E 0 FA A4 1 0 0 0 0 0 0 1 90 10 3
* W: 10 2 A1 3 13 0 0 49 10 3
* R: 10 2 A0 0E 13 1 0E 0 FA A4 1 0 0 0 0 0 0 0 91 10 3
* W: 10 2 A1 1 10 10 4E 10 3
* R: 10 2 93 13 2 12 F1 1 FF 3A 98 9F 0 0 8 FF 0 0 FF 7F FF 7F FD E4 10 3
* R: 10 2 A0 22 10 10 1 0E 0 FA A4 1 0 0 0 0 0 6D 0 3C 9C 25 93 67 8 3C 9C 2A 93 67 0 BB AF 0 0 3 0 0 0 AB 10 3
* W: 10 2 A1 2 4C 2 0F 10 3 <- some sort of reset?
* R: 10 2 A0 0D 4C 1 0E 0 FA A4 1 0 0 0 0 0 2 57 10 3
* W: 10 2 A1 1 13 4B 10 3 <- some sort of reset?
* R: 10 2 A0 0F F0 1 0E 0 FA A4 1 0 0 0 0 0 67 8 0 44 10 3
* R: 10 2 93 13 2 12 F1 1 FF 3A 2D 0 0 0 8 FF 0 0 FF 7F FF 7F FD EE 10 3
*/
// For now, we just use the computer's clock (and so don't get millisecond accuracy)
DateTime thisTime;
thisTime = DateTime.Now;
//if (firstArrived)
//{
// // Check for rollover.
// if (ms < lastMs)
// baseTime = baseTime.AddMilliseconds(uint.MaxValue); // being 8.1715 years
// thisTime = baseTime.AddMilliseconds(ms);
//}
//else
//{
// firstArrived = true;
// thisTime = DateTime.Now;
// baseTime = thisTime.AddMilliseconds(-ms);
//}
//lastMs = ms;
int N2kDataLength = payload[10];
byte[] N2kData = new byte[N2kDataLength];
Array.Copy(payload, 11, N2kData, 0, N2kDataLength);
N2kHeader Header = new N2kHeader(Priority, PGN, Destination, Source);
N2kFrame frame = new N2kFrame(Header, N2kData, thisTime);
OnFrameCreated(frame);
}
public override int ProcessBytes(byte[] bytes, int offset, int size)
{
// Loop through data
int numRead = 0;
for (int i = 0; i < size; i++)
{
byte nextByte = bytes[offset + i];
if (_escapeRead)
{
switch (nextByte)
{
case Escape:
_buffer[_bufferIdx++] = Escape;
break;
case StartOfText:
_bufferIdx = 0;
_headerRead = true;
break;
case EndOfText:
if (!_headerRead)
{
// End of text, but no header read => Came in half way through frame
_escapeRead = false;
return(numRead);
}
else
{
_headerRead = false;
_escapeRead = false;
// Message complete
ActisenseMessage actiMsg = new ActisenseMessage(_buffer, 0);
OnMessageReceived(actiMsg);
// Continue reading.
numRead = i + 1;
break;
}
default:
// Unexpected character !
_headerRead = false;
_escapeRead = false;
return(numRead);
}
_escapeRead = false;
}
else
{
if (nextByte == Escape)
{
_escapeRead = true;
}
else if (_headerRead)
{
_buffer[_bufferIdx++] = nextByte;
}
else
{
// Unknown character. Not escaped, but not part of the message
return(numRead);
}
}
}
// Read entire byte[] given
return(size);
}
