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#include <SPI.h>
#include <Adafruit_GPS.h>
#include <SoftwareSerial.h>
#include <SD.h>
#include <avr/sleep.h>
// Ladyada's logger modified by Bill Greiman to use the SdFat library
// This code shows how to listen to the GPS module in an interrupt
// which allows the program to have more 'freedom' - just parse
// when a new NMEA sentence is available! Then access data when
// desired.
// Tested and works great with the Adafruit Ultimate GPS Shield
// using MTK33x9 chipset
// ------>
// Pick one up today at the Adafruit electronics shop
// and help support open source hardware & software! -ada
// Fllybob added 10 sec logging option
SoftwareSerial mySerial(8, 7);
Adafruit_GPS GPS(&mySerial);
// Set GPSECHO to 'false' to turn off echoing the GPS data to the Serial console
// Set to 'true' if you want to debug and listen to the raw GPS sentences
#define GPSECHO true
/* set to true to only log to SD when GPS has a fix, for debugging, keep it false */
#define LOG_FIXONLY false
// this keeps track of whether we're using the interrupt
// off by default!
boolean usingInterrupt = false;
void useInterrupt(boolean); // Func prototype keeps Arduino 0023 happy
// Set the pins used
#define chipSelect 10
#define ledPin 13
File logfile;
// read a Hex value and return the decimal equivalent
uint8_t parseHex(char c) {
if (c < '0')
return 0;
if (c <= '9')
return c - '0';
if (c < 'A')
return 0;
if (c <= 'F')
return (c - 'A')+10;
// blink out an error code
void error(uint8_t errno) {
if (SD.errorCode()) {
putstring("SD error: ");
Serial.print(card.errorCode(), HEX);
Serial.println(card.errorData(), HEX);
while(1) {
uint8_t i;
for (i=0; i<errno; i++) {
digitalWrite(ledPin, HIGH);
digitalWrite(ledPin, LOW);
for (i=errno; i<10; i++) {
void setup() {
// for Leonardos, if you want to debug SD issues, uncomment this line
// to see serial output
//while (!Serial);
// connect at 115200 so we can read the GPS fast enough and echo without dropping chars
// also spit it out
Serial.println("\r\nUltimate GPSlogger Shield");
pinMode(ledPin, OUTPUT);
// make sure that the default chip select pin is set to
// output, even if you don't use it:
pinMode(10, OUTPUT);
// see if the card is present and can be initialized:
if (!SD.begin(chipSelect, 11, 12, 13)) {
//if (!SD.begin(chipSelect)) { // if you're using an UNO, you can use this line instead
Serial.println("Card init. failed!");
char filename[15];
strcpy(filename, "GPSLOG00.TXT");
for (uint8_t i = 0; i < 100; i++) {
filename[6] = '0' + i/10;
filename[7] = '0' + i%10;
// create if does not exist, do not open existing, write, sync after write
if (! SD.exists(filename)) {
logfile =, FILE_WRITE);
if( ! logfile ) {
Serial.print("Couldnt create ");
Serial.print("Writing to ");
// connect to the GPS at the desired rate
// uncomment this line to turn on RMC (recommended minimum) and GGA (fix data) including altitude
// uncomment this line to turn on only the "minimum recommended" data
// For logging data, we don't suggest using anything but either RMC only or RMC+GGA
// to keep the log files at a reasonable size
// Set the update rate
GPS.sendCommand(PMTK_SET_NMEA_UPDATE_1HZ); // 100 millihertz (once every 10 seconds), 1Hz or 5Hz update rate
// Turn off updates on antenna status, if the firmware permits it
// the nice thing about this code is you can have a timer0 interrupt go off
// every 1 millisecond, and read data from the GPS for you. that makes the
// loop code a heck of a lot easier!
// Interrupt is called once a millisecond, looks for any new GPS data, and stores it
char c =;
// if you want to debug, this is a good time to do it!
#ifdef UDR0
if (c) UDR0 = c;
// writing direct to UDR0 is much much faster than Serial.print
// but only one character can be written at a time.
void useInterrupt(boolean v) {
if (v) {
// Timer0 is already used for millis() - we'll just interrupt somewhere
// in the middle and call the "Compare A" function above
OCR0A = 0xAF;
usingInterrupt = true;
else {
// do not call the interrupt function COMPA anymore
usingInterrupt = false;
void loop() {
if (! usingInterrupt) {
// read data from the GPS in the 'main loop'
char c =;
// if you want to debug, this is a good time to do it!
if (c) Serial.print(c);
// if a sentence is received, we can check the checksum, parse it...
if (GPS.newNMEAreceived()) {
// a tricky thing here is if we print the NMEA sentence, or data
// we end up not listening and catching other sentences!
// so be very wary if using OUTPUT_ALLDATA and trying to print out data
// Don't call lastNMEA more than once between parse calls! Calling lastNMEA
// will clear the received flag and can cause very subtle race conditions if
// new data comes in before parse is called again.
char *stringptr = GPS.lastNMEA();
if (!GPS.parse(stringptr)) // this also sets the newNMEAreceived() flag to false
return; // we can fail to parse a sentence in which case we should just wait for another
// Sentence parsed!
if (LOG_FIXONLY && !GPS.fix) {
Serial.print("No Fix");
// Rad. lets log it!
uint8_t stringsize = strlen(stringptr);
if (stringsize != logfile.write((uint8_t *)stringptr, stringsize)) //write the string to the SD file
if (strstr(stringptr, "RMC") || strstr(stringptr, "GGA")) logfile.flush();
/* End code */