Allows for a GPS module to be connected to a serial port and exposes an easy to use API to get the GPS data.
Fork of MODGPS by
GPS.cpp
- Committer:
- AjK
- Date:
- 2011-04-16
- Revision:
- 3:28a1b60b0f37
- Parent:
- 2:8aa059e7d8b1
- Child:
- 5:7f130f85d5a4
File content as of revision 3:28a1b60b0f37:
/* Copyright (c) 2010 Andy Kirkham Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */ #include "GPS.h" GPS::GPS(PinName tx, PinName rx, const char *name) : Serial(tx, rx, name) { _nmeaOnUart0 = false; _lastByte = 0; switch(_uidx) { case 1: _base = LPC_UART1; break; case 2: _base = LPC_UART2; break; case 3: _base = LPC_UART3; break; default : _base = NULL; break; } _pps = NULL; _ppsInUse = false; if (_base != NULL) attach(this, &GPS::rx_irq); _second100 = new Ticker; _second100->attach_us(this, &GPS::ticktock, GPS_TICKTOCK); } void GPS::ppsAttach(PinName irq, ppsEdgeType type) { if (_pps != NULL) delete(_pps); _pps = new InterruptIn(irq); if (type == ppsRise) _pps->rise(this, &GPS::pps_irq); else _pps->fall(this, &GPS::pps_irq); _ppsInUse = true; } void GPS::ppsUnattach(void) { if (_pps != NULL) delete(_pps); _ppsInUse = false; } double GPS::latitude(void) { double a, b; do { a = thePlace.lat; b = thePlace.lat; } while (a != b); return a; } double GPS::longitude(void) { double a, b; do { a = thePlace.lon; b = thePlace.lon; } while (a != b); return a; } double GPS::altitude(void) { double a, b; do { a = thePlace.alt; b = thePlace.alt; } while (a != b); return a; } GPS_Geodetic * GPS::geodetic(GPS_Geodetic *q) { GPS_Geodetic a; if (q == NULL) q = new GPS_Geodetic; do { memcpy(&a, &thePlace, sizeof(GPS_Geodetic)); memcpy(q, &thePlace, sizeof(GPS_Geodetic)); } while (memcmp(&a, q, sizeof(GPS_Geodetic)) != 0); return q; } GPS_VTG * GPS::vtg(GPS_VTG *q) { GPS_VTG a; if (q == NULL) q = new GPS_VTG; do { memcpy(&a, &theVTG, sizeof(GPS_VTG)); memcpy(q, &theVTG, sizeof(GPS_VTG)); } while (memcmp(&a, q, sizeof(GPS_VTG)) != 0); return q; } void GPS::ticktock(void) { // Increment the time structure by 1/100th of a second. ++theTime; // Test the serial queue. if (process_required) { char *s = buffer[active_buffer == 0 ? 1 : 0]; if (!strncmp(s, "$GPRMC", 6)) { theTime.nmea_rmc(s); cb_rmc.call(); if (!_ppsInUse) theTime.fractionalReset(); } else if (!strncmp(s, "$GPGGA", 6)) { thePlace.nmea_gga(s); cb_gga.call(); } else if (!strncmp(s, "$GPVTG", 6)) { theVTG.nmea_vtg(s); cb_vtg.call(); } process_required = false; } } void GPS::pps_irq(void) { theTime.fractionalReset(); theTime++; // Increment the time/date by one second. cb_pps.call(); } void GPS::rx_irq(void) { uint32_t iir __attribute__((unused)); char c; if (_base) { iir = (uint32_t)*((char *)_base + GPS_IIR); while((int)(*((char *)_base + GPS_LSR) & 0x1)) { c = (char)(*((char *)_base + GPS_RBR) & 0xFF); // strtok workaround. // Found that ,, together (which some NMEA sentences // contain for a null/empty field) confuses strtok() // function. Solution:- Push a "zero" into the string // for missing/empty fields. if (c == ',' && _lastByte == ',') { buffer[active_buffer][rx_buffer_in] = '0'; if (++rx_buffer_in >= GPS_BUFFER_LEN) rx_buffer_in = 0; } // Debugging/dumping data. if (_nmeaOnUart0) LPC_UART0->RBR = c; // Put the byte into the string. buffer[active_buffer][rx_buffer_in] = c; if (++rx_buffer_in >= GPS_BUFFER_LEN) rx_buffer_in = 0; // Save for next time an irq occurs. See strtok() above. _lastByte = c; // If end of NMEA sentence flag for processing. if (c == '\n') { active_buffer = active_buffer == 0 ? 1 : 0; process_required = true; rx_buffer_in = 0; } } } }