/// <summary>
/// Parse a depth sentence with this structure:
/// DPT,d.d,o.o
/// d.d: depth, meters
/// o.o: offset from transducer
/// </summary>
/// <param name="talkerId"></param>
/// <param name="sentence"></param>
private void ParseDepth(string talkerId, string[] words, string sentence)
{
if (words.Length < 2)
{
DebugLog.WriteLine("Invalid DPT sentence: " + sentence);
return;
}
double depth;
try
{
depth = Double.Parse(words[1]);
}
catch (Exception e)
{
DebugLog.WriteLine("Could not parse double: " + sentence + " e:" + e.ToString());
return;
}
DebugLog.WriteLine("depth update: depth=" + depth);
if (DepthEvent != null)
{
var args = new NmeaDepthEventArgs(depth, 0);
DepthEvent(this, args);
}
}
/// <summary>
/// Parse a magnetic heading sentence with this structure:
/// HDM,x.x,M
/// x.x: Heading Degrees, magnetic
/// M: magnetic
/// </summary>
/// <param name="talkerId"></param>
/// <param name="sentence"></param>
private void ParseHeadingMagnetic(string talkerId, string[] words, string sentence)
{
if (words.Length != 3)
{
DebugLog.WriteLine("Invalid HDM sentence: " + sentence);
return;
}
double heading;
try
{
heading = Double.Parse(words[1]);
if (heading < 0 || heading > 360)
{
DebugLog.WriteLine("Invalid heading: " + sentence);
return;
}
}
catch (Exception e)
{
DebugLog.WriteLine("Could not parse double: " + sentence + " e:" + e.ToString());
return;
}
DebugLog.WriteLine("magnetic heading update: " + heading);
if (HeadingEvent != null)
{
var args = new NmeaHeadingEventArgs(heading);
HeadingEvent(this, args);
}
}
/// <summary>
/// Write a NMEA sentence to the serial port. This function prefixes the supplied sentence with a
/// talker ID and postfixes it with a checksum.
/// </summary>
/// <exception cref="IOException">IOException is thrown when the write fails</exception>
/// <param name="sentence">The sentence to write</param>
private void WriteSentence(string sentence)
{
// prefix the talkerId
string fulldata = talkerId + sentence;
// the checksum
byte checksum = 0;
// compute checksum
for (int i = 0; i < fulldata.Length; i++)
{
var c = (byte)fulldata[i];
checksum ^= c;
}
// append checksum
string outputdata = "$" + fulldata + "*" + checksum.ToString("x2");
byte[] outputbytes = Encoding.UTF8.GetBytes(outputdata + "\r\n");
lock (this)
{
DebugLog.WriteLine("sending:" + outputdata);
this.m_serialPort.Write(outputbytes, 0, outputbytes.Length);
}
}
public void Go()
{
// turn of Netduino devices that we don't need
PowerManagement.SetPeripheralState(Peripheral.Ethernet, false);
PowerManagement.SetPeripheralState(Peripheral.PowerLED, false);
PowerManagement.SetPeripheralState(Peripheral.SDCard, false);
// initalize the serial ports
m_serialPort = new SerialPort("COM1", 38400, Parity.None, 8, StopBits.One);
m_serialPort.Open();
m_nmeaInputPort = new NmeaInputPort(m_serialPort);
m_oled = new Newhaven25664OledDriver(
chipSelect: Pins.GPIO_PIN_D10,
reset: Pins.GPIO_PIN_D9,
dc: Pins.GPIO_PIN_D8);
m_oled.Initialize();
m_oled.ClearDisplay();
m_oled.TestPattern();
Thread.Sleep(1000);
m_oled.ClearDisplay();
InputPort leftButton = new InputPort(Pins.GPIO_PIN_D7, false, Port.ResistorMode.PullUp);
if (!leftButton.Read())
{
// debug mode
//m_nmeaInputPort.RawDataDebugEvent += new NmeaInputDebugEventHandler(m_nmeaInputPort_RawDataDebugEvent);
m_nmeaInputPort.ParsedDataDebugEvent += new NmeaInputParsedDebugEventHandler(m_nmeaInputPort_ParsedDataDebugEvent);
m_debugFont = new OledFont(SailboatComputer.Properties.Resources.BinaryResources.fixed5x7);
m_nmeaInputPort.Initialize();
while (true)
{
Thread.Sleep(Int16.MaxValue);
}
}
else
{
leftButton.Dispose();
leftButton = null;
DebugLog.WriteLine("free memory (before fonts) = " + Microsoft.SPOT.Debug.GC(true));
m_ui = new SimpleUserInterface(m_oled, Pins.GPIO_PIN_D7, Pins.GPIO_PIN_D6);
DebugLog.WriteLine("free memory (after fonts) = " + Microsoft.SPOT.Debug.GC(true));
// hook up NMEA events
m_nmeaInputPort.WindEvent += new NmeaWindEventHandler(m_nmeaInputPort_WindEvent);
m_nmeaInputPort.COGSOGEvent += new NmeaCOGSOGEventHandler(m_nmeaInputPort_CogSogEvent);
m_nmeaInputPort.DepthEvent += new NmeaDepthEventHandler(m_nmeaInputPort_DepthEvent);
m_nmeaInputPort.Initialize();
while (true)
{
Thread.Sleep(Int16.MaxValue);
}
}
}
/// Output a Wind Heading and velocity sentence with this format:
/// MWV,x.x,R,v.v,M,A
/// x.x = relative heading of the wind
/// R = relative
/// v.v = the wind velocity in MPH
/// M/N/K = mph, knots, kph
private void ParseWindSpeedAndVelocity(string talkerId, string[] words, string sentence)
{
if (words.Length != 6)
{
DebugLog.WriteLine("invalid MWV sentence: " + sentence);
return;
}
int relativeHeading;
double velocity;
try
{
int period = words[1].IndexOf('.');
if (period > 0)
{
relativeHeading = Int32.Parse(words[1].Substring(0, period));
}
else
{
relativeHeading = Int32.Parse(words[1]);
}
velocity = Double.Parse(words[3]);
}
catch (Exception e)
{
DebugLog.WriteLine("Could not parse: " + sentence + " e:" + e.ToString());
return;
}
// convert velocity to knots
switch (words[4])
{
case "M":
velocity *= 0.868976242;
break;
case "K":
velocity *= 0.539956803;
break;
case "N":
// velocity is already in knots
break;
default:
DebugLog.WriteLine("Invalid wind speed: " + sentence);
return;
}
DebugLog.WriteLine("Wind velocity update: h=" + relativeHeading + " v=" + velocity);
if (WindEvent != null)
{
var args = new NmeaWindEventArgs(relativeHeading, velocity);
WindEvent(this, args);
}
}
/// <summary>
/// Parse VTG verb with this structure:
/// VTG,t.t,T,m.m,M,s.s,N,k.k,K,m
/// t.t: true heading
/// m.m: mag heading
/// s.s: speed knots
/// k.k: speed k/mh
/// </summary>
/// <param name="talkerId"></param>
/// <param name="words"></param>
/// <param name="sentence"></param>
private void ParseCOGandSOG(string talkerId, string[] words, string sentence)
{
double cogT;
double cogM;
double sog;
if (words.Length < 6)
{
DebugLog.WriteLine("Invalid VTG sentence: " + sentence);
return;
}
try
{
cogT = Double.Parse(words[1]);
if (cogT < 0 || cogT > 360)
{
DebugLog.WriteLine("Invalid heading: " + sentence);
return;
}
cogM = Double.Parse(words[3]);
if (cogM < 0 || cogM > 360)
{
DebugLog.WriteLine("Invalid heading: " + sentence);
return;
}
sog = Double.Parse(words[5]);
}
catch
{
DebugLog.WriteLine("Invalid VTG sentence: " + sentence);
return;
}
if (COGSOGEvent != null)
{
var args = new NmeaCOGSOGEventArgs(cogT, cogM, sog);
COGSOGEvent(this, args);
}
}
/// <summary>
/// Parse a complete NMEA sentence
/// </summary>
/// <param name="sentence">The sentence to parse</param>
private void ParseNmeaSentence(string sentence)
{
DebugLog.WriteLine("NmeaInputPort: " + sentence);
// shortest legal would be:
// $xxVVV.*xx
if (sentence.Length < 10)
{
DebugLog.WriteLine("invalid sentence, too short:" + sentence);
return;
}
// pull off the global structure of the sentence
string verb = sentence.Substring(3, 3);
// see if we have a parser for this verb. If not we'll jump out now
SentenceParser parser = (SentenceParser)m_sentenceParsers[verb];
if (parser == null)
{
DebugLog.WriteLine("skipped unknown verb: " + sentence);
long processingTime = DateTime.Now.Ticks - m_startProcessing;
if (this.ParsedDataDebugEvent != null)
{
this.ParsedDataDebugEvent(this, new NmeaInputParsedDebugEventArgs(sentence, processingTime));
}
return;
}
// must start with $
if (sentence[0] != '$')
{
DebugLog.WriteLine("invalid sentence, no prefix: " + sentence);
return;
}
string talkerId = sentence.Substring(1, 2);
string checksumSuffix = sentence.Substring(sentence.Length - 3);
// the checksum is the last 3 characters and starts with *
if (checksumSuffix[0] != '*')
{
DebugLog.WriteLine("Invalid NMEA, weird checksum: " + sentence);
return;
}
// the digits in the checksum are hex, convert them to a byte
byte checksum;
try
{
checksum = (byte)Convert.ToInt32(checksumSuffix.Substring(1), 16);
}
catch (Exception e)
{
DebugLog.WriteLine("Invalid NMEA, bad checksum: " + sentence + " e:" + e.ToString());
return;
}
// compute the checksum and see if it matches
byte computedChecksum = 0;
string checkedString = sentence.Substring(1, sentence.Length - 4);
for (int i = 0; i < checkedString.Length; i++)
{
var c = (byte)checkedString[i];
computedChecksum ^= c;
}
if (checksum != computedChecksum)
{
DebugLog.WriteLine("Checksum failed: " + sentence);
return;
}
// we send the sentence without the prefix and suffix to verb parsers
string usefulSentence = sentence.Substring(3, sentence.Length - 6);
// call the parser
parser(talkerId, usefulSentence.Split(','), sentence);
if (this.ParsedDataDebugEvent != null)
{
long processingTime = DateTime.Now.Ticks - m_startProcessing;
this.ParsedDataDebugEvent(this, new NmeaInputParsedDebugEventArgs(sentence, processingTime));
}
}