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 1:8e24e633f8d8:

#include "mbed.h" 
#include <string>

//set up the message buffer to be filled by the GPS read process

#include "MODSERIAL.h"
#include "SDFileSystem.h"      //imported using the import utility    

//general digital I/O specifications for this application
//SDFileSystem(PinName mosi, PinName miso, PinName sclk, PinName cs, const char* name);
SDFileSystem sd(p11,p12,p13,p14,"sd");
DigitalIn sd_detect(p27);
DigitalOut ppsled(LED1);        //blink an LED at the 1PPS
DigitalOut trig1led(LED2);      //blink an LED at the camera trigger detection
DigitalOut rxMsg(LED3);
DigitalOut txMsg(LED4);
//DigitalOut recordDataled(LED4); //set the led when the record is on

//hardware trigger mechanization for bulb shutter commands
DigitalInOut fire(p29);     //connected to the tip of 2.5mm connector (T2i)
DigitalInOut pre_fire(p30); //connected to the mid-connection for 2.5mm connector (T2i)

//USB serial data stream back to the PC
Serial toPC(USBTX, USBRX);      //connect the GPS TX, RX to p9 and p10

Timer timeFromStart;

bool detectedGPS1PPS = false;       //flag set in the ISR and reset after processing the 1PPS event
int PPSCounter = 0;                 //counts the 1PPS occurrences
int byteCounter = 0;                //byte counter -- zeroed at 1PPS
unsigned short perSecMessageCounter=0; //counts the number of messages in a sec based on the header detection
bool messageDetected = false;       //have detected a message header
unsigned long IMUbytesWritten = 0;  //counts the IMU bytes written by the fwrite() to the SD card 
int savedByteCounter = 0;           //save ByteCounter at the 1PPS for display in main
int savedPerSecMessageCounter=0;    //saved PerSecMsgCounter for display in main
int savedIMUClockCounter=0;         //saved at the 1PPS for later diaplay from main
bool camera1EventDetected = false;  //flag from ISR indicating a clock event occurred
double camera1Time;                 //GPS time of the camera event 
int TotalBadCRCmatches = 0;         //counter for the bad CRC matches for all GPS messages

volatile int PPSTimeOffset = 0;

// the below should become classes
#include "OEM615.h"         //OEM615 GPS activities
#include "ADIS16488.h"      //ADIS16488 activities
#include "PCMessaging.h"    //PC messaging activities

//ISR for detection of the GPS 1PPS
void detect1PPSISR(void)
    timeFromPPS.reset();                    //reset the 1PPS timer upon 1PPS detection
    //note -- the below accounts for time information becoming available AFTER the 1PPS event
    PPSTimeOffset++;                //counts 1PPS events between matching POS and VEL messages
    //covers the case where the PPS ISR interrupts the IMU data ready ISR
    if(IMUDataReady) IMUtimeFrom1PPS = 0;
    savedByteCounter = byteCounter;         //save byteCounter for display in main
    savedPerSecMessageCounter = perSecMessageCounter;   //save for display un main
    byteCounter = 0;                        //countes bytes between 1PPS events 
    perSecMessageCounter = 0;               //counts GPS messages between 1PPS events
    GPS_COM1.rxBufferFlush();               //flush the GPS serial buffer
    detectedGPS1PPS = true;         //set false in the main when 1PPS actions are complete
    PPSCounter++;                   //count number of 1PPS epoch
    ppsled = !ppsled;               //blink an LED at the 1PPS

//set up the USB port and the GPS COM port
FILE *fpNav = NULL;  //file pointer to the nav file on the SD card
void setupCOM(void)
    //system starts with GPS in reset active
    //dis-engage the reset to get the GPS started
    GPS_Reset=1; wait_ms(1000); 
    //establish 1PPS ISR 
    //set the USB serial data rate -- rate must be matched at the PC end
    //This the serial communication back to the the PC host
    //Launch the C++ serial port read program there to catch the ASCII characters
    //toPC.baud(9600); wait_ms(100);    
    toPC.baud(8*115200); wait_ms(100);
    //toPC.baud(1*115200); wait_ms(100);
    toPC.printf("\n\n released GPS from RESET and set to high baud rate \n\n");
    //just wait to launch the GPS receiver
    for (int i=0; i<5; i++) { toPC.printf(" to start: %3d \n", 4-i); wait(1); }

    if (sd_detect == 0)
        mkdir("/sd/Data", 0777);
        toPC.printf(" SD card not present \n");
    //NOTE:  we do not assume that the GPS receiver has been pre-set up for the WALDO_FCS functionality
    //we alwsys start with a reset and reprogram the receiver with our data out products
    // this prevents failure because of a blown NVRAM as occurred for the older camera systems
    //this is the COM1 port from th GPS receiuver to the mbed
    //it should be always started at 9600 baud because thats the default for the GPS receiver 
    GPS_COM1.baud(9600); wait_ms(100);
    // this ASCII command sets up the serial data from the GPS receiver on its COM1
    char ch7[] = "serialconfig COM1 9600 n 8 1 n off";
    // this is a software reset and has the same effect as a hardware reset (why do it?) 
    //char ch0[] = "RESET"; 
    //this command stops all communication from the GPS receiver on COM1
    //logs should still be presented on USB port so the Novatel CDU application can be used on the PC in parallel
    char ch1[] = "unlogall COM1";
    //set the final baud rate that we will use from here  
    //allowable baud rate values: 9600 115200 230400 460800 921600
    //char ch2[] = "serialconfig COM1 921600 n 8 1 n off";
    char ch2[] = "serialconfig COM1 115200 n 8 1 n off";
    //the below commands request the POS, VEL, RANGE, and TIME messages
    char ch3[] = "log COM1 BESTPOSB ONTIME 1";   //messageID = 42 
    char ch4[] = "log COM1 BESTVelB ONTIME 1";   //messageID = 99
    char ch5[] = "log COM1 RANGEB ONTIME 1";     //messageID = 43
    //char ch6[] = "log COM1 TIMEB ONTIME 1";      //messageID = 101
    //set up VARF to be 100Hz with 1X10^4 * 10^-8 = 10^-4 sec (10usec) pulse width
    //in fact, we do not use this output but it is available.
    //originally planned to use this to command the IMU data
    //char ch8[] = "FREQUENCYOUT enable 10000 1000000";
    toPC.printf("set serial config \n");
    sendASCII(ch7, sizeof(ch7)); wait_ms(500);
    //sendASCII(ch0, sizeof(ch0));  
    toPC.printf("unlog all messages \n");
    sendASCII(ch1, sizeof(ch1)); wait_ms(500);
    toPC.printf("log BESTPOSB on COM1 \n");
    sendASCII(ch3, sizeof(ch3)); wait_ms(500);
    toPC.printf("log BESTVELB on COM1\n");
    sendASCII(ch4, sizeof(ch4)); wait_ms(500);
    toPC.printf("log RANGEB on COM1\n");
    sendASCII(ch5, sizeof(ch5)); wait_ms(500);
    //toPC.printf("log TIMEB om COM1 \n");
    //sendASCII(ch6, sizeof(ch6)); wait_ms(100);
    //toPC.printf("Set up th VARF signal \n"); 
    //sendASCII(ch8, sizeof(ch8)); wait_ms(500);
    //set GPS output COM1 to the final high rate
    toPC.printf("set the COM ports to high rate\n");
    sendASCII(ch2, sizeof(ch2)); wait_ms(500);
    //set the mbed COM port to match the GPS transmit rate
    //the below baud rate must match the COM1 rate coming from the GPS receiver 
    GPS_COM1.baud(115200); wait_ms(500);  //without this wait -- the baud rate is not detected when using MODSERIAL     
    //GPS_COM1.baud(921600); wait_ms(500);  //without this wait -- the baud rate is not detected when using MODSERIAL     

//  mbed main to support the Waldo_FCS
int main() {
    //these are structures for the to GPS messages that must be parsed
    OEM615BESTPOS posMsg;   //BESTPOS structure in OEMV615.h that has matching time to a BESTVEL message
    OEM615BESTPOS curPos;   //BESTPOS structure in OEMV615.h
    OEM615BESTVEL velMsg;   //BESTVEL structure in OEMV615.h that has matching time to a BESTPOS message
    OEM615BESTVEL curVel;   //BESTVEL structure in OEMV615.h

    fire.output();  //set the fire pin as outoput
    pre_fire.output();  //set the pre-fire pin as output
    //set up for the first trigger
    fire = 1;
    pre_fire = 1;
    //set up the GPS and mbed COM ports
    //set up the ADIS16488 

    setUpMessages();  //set up the expected text message commands frm the PC 
    //set up the interrupt to catch the GPS receiver serial bytes as they are presented
    GPS_COM1.attach(&readSerialByte, MODSERIAL::RxIrq);
    timeFromPPS.start();  //start the time for measuring time from 1PPS events
    toPC.printf("\n\n top of the main loop \n\n");
    int totalBytesWritten = 0;
    /*establish the initial value for the CRC recursion atter the header
    unsigned long CRC = 0;
    CRC32Value(CRC, 0xAA);
    CRC32Value(CRC, 0x44);
    CRC32Value(CRC, 0x12);
    CRC32Value(CRC, 0x1C);
    //this results in a value of:   0x39b0f0e1
    toPC.printf(" CRC after AA44121C header: %08x \n", CRC);
    recordData = true;
    sendRecData = true;     
    unsigned long cyclesPerSec = 0;
    bool GPSdataWritten = false;
    //while(PPSCounter < 300)
    // top of the while loop
        //read the USB serial data from the PC to check for commands
        //in the primary real-time portion, there are no bytes from the PC so this has no impact
        processPCmessages(fpNav, posMsg, velMsg);
            //pre-fire the trigger using the mid-body 2.5mm connection (T2i)
            pre_fire = 0;  //pin30 (midbody of connector) set to zero
            wait(.01f);  //wait for 0.25 secs
            fire = 0; //fire the trigger using the tip connection
            fire = 1;
            pre_fire = 1;
            unsigned long triggerTime = GPSTimemsecs + PPSTimeOffset*1000 + timeFromPPS.read_us()/1000.0;
            toPC.printf("WMsg TRIGGERTIME %10d \n", triggerTime);
            fireTrigger = false;

        //below is where we process the complete stored GPS message for the second
        //The !IMUDataReady test prevents the IMU and GPS data from being written 
        //to disk on the same pass through this loop  
        if (completeMessageAvailable && !IMUDataReady)
            msgHdr = *((MESSAGEHEADER*)&msgBuffer[messageLocation[savedMessageCounter-1]]);
            //these times are used to tag the IMU sample time. PPSTimeOffset increments by 1 exactly at the 1PPS event (in the 1PPS ISR)
            //GPSTimemsecs increments by 1 for each new GPS measurement -- note that the below computations are actually
            //done at the receipt of each GPS message. This is OK because each message has the same time in its header.
            //Thus GPSTimemsecs increments by 1 here while GPSTimemsecs effectively decrements by 1.
            //This handles IMU time tagging between the 1PPS event and the first receipt of a new GPS time.

            GPSTimemsecs = msgHdr.GPSTime_msecs;  //time in GPS message header
            PPSTimeOffset = 0;                    //incremented by 1 in the PPS ISR
            unsigned long msgCRC = *((unsigned long*)&msgBuffer[messageLocation[savedMessageCounter-1] + 28 + msgHdr.messageLength]);
            //toPC.printf("tmeFrom1PPS= %5d  ID= %3d Ln = %3d computedCRC= %08x msgCRC= %08x msgCntr = %3d CRCerr=%4d\n", 
            //    timeFromPPS.read_us(), msgHdr.messageID, msgHdr.messageLength, computedCRC, msgCRC, savedMessageCounter, TotalBadCRCmatches);
            if ( msgCRC != computedCRC)
                toPC.printf(" bad CRC match for messageID %3d total CRC errors = %4d \n",  
                    msgHdr.messageLength, TotalBadCRCmatches++);
            if      (msgHdr.messageID == 42)
                curPos = *((OEM615BESTPOS*)&msgBuffer[messageLocation[savedMessageCounter-1]]);
                posMsg = curPos;
                if (streamPos)
                        toPC.printf("BESTPOS %5d %1d %8.5lf %9.5lf %5.3lf %d %d\n",
                                          curPos.msgHeader.GPSTime_msecs,  curPos.solStatus,
                                          curPos.latitude, curPos.longitude, curPos.height,
                                          curPos.numSV, curPos.numSolSV);
            else if (msgHdr.messageID == 99)  
                curVel = *((OEM615BESTVEL*)&msgBuffer[ messageLocation[savedMessageCounter-1] ]);
                //toPC.printf("BESTVEL  vel: horizontalSpeed= %5.3f heading=%5.1f verticalSpeed=%4.2f \n", 
                //    curVel.horizontalSpeed,  curVel.heading,  curVel.verticalSpeed );
                velMsg = curVel;
            if (recordData && (fpNav != NULL) && (byteCounter > 0))
                int totalMessageLength = 28 + msgHdr.messageLength + 4;  //header length + message Length + CRC word size
                totalBytesWritten += fwrite(&msgBuffer[messageLocation[savedMessageCounter-1]], 1, totalMessageLength, fpNav);  // this writes out a complete set of messages for this sec
            completeMessageAvailable = false;
        //write the GPS data to the SD card
        if (!IMUDataReady && !GPSdataWritten && timeFromPPS.read_us() > 500000 && recordData && (fpNav != NULL))
                totalBytesWritten += fwrite(&msgBuffer, 1, byteCounter, fpNav);
                GPSdataWritten = true;
        //the IMU data record is read from the SPI in the ISR and the IMUDataReady is set true
        //we write the IMU data here
        if (IMUDataReady)  //IMUDataReady is true if we have a recent IMU data record
            //write the IMU data
            if ( recordData && (fpNav != NULL) )
                //delTimeOfWrite = timeFromStart.read_us();
                if (fillingPingWritingPong) fwrite(&imuPong, 1, IMUrecArraySize*sizeof(IMUREC), fpNav);
                else                        fwrite(&imuPing, 1, IMUrecArraySize*sizeof(IMUREC), fpNav);
                //delTimeOfWrite = (unsigned long)((unsigned long)timeFromStart.read_us() - delTimeOfWrite);
                //if (delTimeOfWrite > maxWriteTime) maxWriteTime = delTimeOfWrite;                
            IMUDataReady = false;
        if (camera1EventDetected)  //we have detected a camera trigger event
            toPC.printf("WMsg TRIGGERTIME %5.3lf\n", camera1Time);
            camera1EventDetected = false;
        if (detectedGPS1PPS)  //true if we are exactly at a 1PPS event detection
            //toPC.printf("PPS=%4d stat=%1d bytes=%3d GPSMsgs=%2d  #write=%8d cycles=%6d\n", 
            //                PPSCounter, posMsg.solStatus, savedByteCounter, savedPerSecMessageCounter, 
            //                totalBytesWritten, cyclesPerSec );
            cyclesPerSec = 0;
            totalBytesWritten = 0;
            GPSdataWritten = false;
            IMURecordCounter = 0;
            detectedGPS1PPS = false;
    toPC.printf(" normal termination \n");