this version has all of Jim's fixes for reading the GPS and IMU data synchronously

Dependencies:   MODSERIAL SDFileSystem mbed SDShell CRC CommHandler FP LinkedList LogUtil



File content as of revision 29:dead10cce6e9:

#include "crc.h"

//GPS-specific pins
DigitalOut GPS_Reset(p18);      //GPS RESET line
InterruptIn PPSInt(p15);        // GPS 1PPS (timemark) from the OEM615
InterruptIn IMUClock(p17);

Timer timeFromPPS;
unsigned long GPSTimemsecs = 0;

//mbed tx/rx interface to the GPS COM1 port
MODSERIAL GPS_COM1(p9,p10);  //this serial port communicates with the GPS receiver serial port (COM1)

bool loadingMessageBuffer = false;

const unsigned short maxGPSbytesPerSec = 512;

int messagePerSecCounter = 0;
unsigned char msgBuffer0[maxGPSbytesPerSec];  //array to contain one full second of GPS bytes
unsigned char msgBuffer1[maxGPSbytesPerSec];  //array to contain one full second of GPS bytes
unsigned char msgBuffer2[maxGPSbytesPerSec];  //array to contain one full second of GPS bytes
int GPSbyteCounter0 = 0;
int GPSbyteCounter1 = 0;
int GPSbyteCounter2 = 0;
bool message0Complete = false;
bool message1Complete = false;
bool message2Complete = false;

void sendASCII(char* ASCI_message, int numChars)
    //send an ASCII command to the GPS receiver

    //char ASCI_message[] = "unlogall COM1";
    int as = numChars - 1;
    unsigned char CR = 0x0d;  //ASCII Carriage Return
    unsigned char LF = 0x0a;  //ASCII Line Feed
    //printf("%s", ch);

    for (int i=0; i<as; i++) GPS_COM1.putc(ASCI_message[i]); 
    GPS_COM1.putc(CR);   //carriage return at end
    GPS_COM1.putc(LF);   //line feed at end

//see the mbed COOKBOOK for MODSERIAL
//MODSERIAL is an easy to use library that extends Serial to add fully buffered input and output.
void readSerialByte(MODSERIAL_IRQ_INFO *q)
    MODSERIAL *serial = q->serial;      //see example of MODSERIAL usage in cookbook
    unsigned char synch0 = serial->getc();  //get the next byte

    //all OEM615 GPS ASCII messages begin with the unique character: "#"
    //read til we get a "#" and then start storing the message
    if (synch0 == '#')
        if     (messagePerSecCounter == 0)  GPSbyteCounter0 = 0;
        else if(messagePerSecCounter == 1)  GPSbyteCounter1 = 0;
        else if(messagePerSecCounter == 2)  GPSbyteCounter2 = 0;
        loadingMessageBuffer = true;

    if     (messagePerSecCounter == 0)  { msgBuffer0[GPSbyteCounter0 % maxGPSbytesPerSec] = synch0; GPSbyteCounter0++; }
    else if(messagePerSecCounter == 1)  { msgBuffer1[GPSbyteCounter1 % maxGPSbytesPerSec] = synch0; GPSbyteCounter1++; }
    else if(messagePerSecCounter == 2)  { msgBuffer2[GPSbyteCounter2 % maxGPSbytesPerSec] = synch0; GPSbyteCounter2++; }
    //stop storing the message when we get a LF
    if (synch0 == 0x0a /* LF*/)   //test for line feed
        if     (messagePerSecCounter == 0)  message0Complete = true;
        else if(messagePerSecCounter == 1)  message1Complete = true;
        else if(messagePerSecCounter == 2)  message2Complete = true;
        messagePerSecCounter++;        //count the messages per second
    //how this can fail??
    //  1) get noisy # occurrences (unique starting character)
    //  2) get noisy LF occurrences (unique ending character)
    //  3) get noisy data packet values or extra values
    //  4) we will also need to vet the data on the PC side
    //  5) here, we should do minimal testing and just pass the data as is