OEM615.h

00001 #include "crc.h"
00002 
00003 //GPS-specific pins
00004 DigitalOut GPS_Reset(p18);      //GPS RESET line
00005 InterruptIn PPSInt(p15);        // GPS 1PPS (timemark) from the OEM615
00006 InterruptIn IMUClock(p17);
00007 
00008 Timer timeFromPPS;
00009 unsigned long GPSTimemsecs = 0;
00010 
00011 //mbed tx/rx interface to the GPS COM1 port
00012 MODSERIAL GPS_COM1(p9,p10);  //this serial port communicates with the GPS receiver serial port (COM1)
00013 
00014 bool loadingMessageBuffer = false;
00015 
00016 const unsigned short maxGPSbytesPerSec = 2048;
00017 
00018 int messagePerSecCounter = 0;
00019 char msgBuffer0[2048];  //array to contain one full second of GPS bytes
00020 char msgBuffer1[512];  //array to contain one full second of GPS bytes
00021 char msgBuffer2[512];  //array to contain one full second of GPS bytes
00022 int GPSbyteCounter0 = 0;
00023 int GPSbyteCounter1 = 0;
00024 int GPSbyteCounter2 = 0;
00025 bool message0Complete = false;
00026 bool message1Complete = false;
00027 bool message2Complete = false;
00028 
00029 ////////////////////////////////////////////////////////////
00030 //hotstart procedure
00031 ////////////////////////////////////////////////////////////
00032 // Novatel OEM615 startup messages:
00033 //   setapproxtime 1605 425384       // GPSWeek & GPSSeconds
00034 //   setapproxpos 51.116 -114.038 0  //lat, lon, alt
00035 ////////////////////////////////////////////////////////////
00036 //  how to use?
00037 //  Assumes a certain power-up sequence: WALDO_FCS must be running on the PC??
00038 //  unlikely this start-up sequence will work!!
00039 //  PC MAY generates a startUp message that is checked for before the GPS RX starts
00040 //  mbed looks for the startup message for 1 sec.
00041 //  startUp message contains: Last PCTime, lastLat, lastLon, LastAlt, LastGPSWeek, LastGPSSeconds
00042 //  If it is found, send the startup messages to the receiver
00043 //  if it is not found, then just start without the messages (cold start)
00044 //  On the PC side, check for a startUp file stored within the .exe folder.
00045 //  However, if the PC clock time between now and the lastStart is > 24 hours, ignore startup file
00046 //  if the startUp file IS PRESENT, use it to send the startUp message
00047 //  After reading the startUp file on the PC, always delete it.
00048 //  Every time the system enters "FINESTEERING", save the StartUp file
00049 
00050 void sendASCII(char* ASCI_message, int numChars)
00051 {
00052     /////////////////////////////////////////////////
00053     //send an ASCII command to the GPS receiver
00054     /////////////////////////////////////////////////
00055 
00056     //char ASCI_message[] = "unlogall COM1";
00057     int as = numChars - 1;
00058     unsigned char CR = 0x0d;  //ASCII Carriage Return
00059     unsigned char LF = 0x0a;  //ASCII Line Feed
00060     
00061     //printf("%s", ch);
00062     //printf("\n");
00063 
00064     for (int i=0; i<as; i++) GPS_COM1.putc(ASCI_message[i]); 
00065     GPS_COM1.putc(CR);   //carriage return at end
00066     GPS_COM1.putc(LF);   //line feed at end
00067 };
00068 
00069 
00070 //see the mbed COOKBOOK for MODSERIAL
00071 //MODSERIAL is an easy to use library that extends Serial to add fully buffered input and output.
00072 void readSerialByte(MODSERIAL_IRQ_INFO *q)
00073 { 
00074     MODSERIAL *serial = q->serial;      //see example of MODSERIAL usage in cookbook
00075     unsigned char synch0 = serial->getc();  //get the next byte
00076     
00077     totalGPSBytes++;
00078 
00079     //all OEM615 GPS ASCII messages begin with the unique character: "#"
00080     //read til we get a "#" and then start storing the message
00081     if (synch0 == '#')
00082     {
00083         if     (messagePerSecCounter == 0)  GPSbyteCounter0 = 0;
00084         else if(messagePerSecCounter == 1)  GPSbyteCounter1 = 0;
00085         else if(messagePerSecCounter == 2)  GPSbyteCounter2 = 0;
00086         //loadingMessageBuffer = true;
00087     }
00088 
00089     if     (messagePerSecCounter == 0)  { msgBuffer0[GPSbyteCounter0 % 1024] = synch0; GPSbyteCounter0++; }
00090     else if(messagePerSecCounter == 1)  { msgBuffer1[GPSbyteCounter1 % 512]  = synch0; GPSbyteCounter1++; }
00091     else if(messagePerSecCounter == 2)  { msgBuffer2[GPSbyteCounter2 % 512]  = synch0; GPSbyteCounter2++; }
00092     
00093     //stop storing the message when we get a LF
00094     if (synch0 == 0x0a /* LF*/)   //test for line feed
00095     {
00096         //as further confirmation, we could test the prior byte for a CR = 0x0d;
00097         
00098         if     (messagePerSecCounter == 0)  
00099         { 
00100             if ( msgBuffer0[GPSbyteCounter0 - 2] == 0x0d) //ensure the two byte end of message
00101                 message0Complete = true;
00102         }
00103         else if(messagePerSecCounter == 1)  
00104         {
00105             if ( msgBuffer0[GPSbyteCounter0 - 2] == 0x0d) //ensure the two byte end of message
00106                 message1Complete = true;
00107             }
00108         else if(messagePerSecCounter == 2)  
00109         {
00110             if ( msgBuffer0[GPSbyteCounter0 - 2] == 0x0d) //ensure the two byte end of message
00111                 message2Complete = true;
00112         }
00113         messagePerSecCounter++;        //count the messages per second
00114     }
00115     
00116     //how this can fail??
00117     //  1) get noisy # occurrences (unique starting character)
00118     //  2) get noisy LF occurrences (unique ending character)
00119     //  3) get noisy data packet values or extra values
00120     //  4) we will also need to vet the data on the PC side
00121     //  5) here, we should do minimal testing and just pass the data as is 
00122     
00123 };
00124