ESP32-PaxCounter/src/gpsread.cpp
2019-09-01 00:11:20 +02:00

167 lines
4.4 KiB
C++

#if (HAS_GPS)
#include "globals.h"
// Local logging tag
static const char TAG[] = __FILE__;
// we use NMEA $GPZDA sentence field 1 for time synchronization
// $GPZDA gives time for preceding pps pulse, but does not has a constant offset
TinyGPSPlus gps;
TinyGPSCustom gpstime(gps, "GPZDA", 1); // field 1 = UTC time
static const String ZDA_Request = "$EIGPQ,ZDA*39\r\n";
gpsStatus_t gps_status = {0};
TaskHandle_t GpsTask;
#ifdef GPS_SERIAL
HardwareSerial GPS_Serial(1); // use UART #1
static uint16_t nmea_txDelay_ms =
(tx_Ticks(NMEA_FRAME_SIZE, GPS_SERIAL) / portTICK_PERIOD_MS);
#else
static uint16_t nmea_txDelay_ms = 0;
#endif
// initialize and configure GPS
int gps_init(void) {
int ret = 1;
if (!gps_config()) {
ESP_LOGE(TAG, "GPS chip initializiation error");
return 0;
}
#ifdef GPS_SERIAL
GPS_Serial.begin(GPS_SERIAL);
ESP_LOGI(TAG, "Using serial GPS");
#elif defined GPS_I2C
Wire.begin(GPS_I2C, 400000); // I2C connect to GPS device with 400 KHz
Wire.beginTransmission(GPS_ADDR);
Wire.write(0x00); // dummy write
ret = Wire.endTransmission(); // check if chip is seen on i2c bus
if (ret) {
ESP_LOGE(TAG,
"Quectel L76 GPS chip not found on i2c bus, bus error %d. "
"Stopping GPS-Task.",
ret);
ret = 0;
} else {
ESP_LOGI(TAG, "Quectel L76 GPS chip found");
}
#endif
return ret;
} // gps_init()
// detect gps chipset type and configure it with device specific settings
int gps_config() {
int rslt = 1; // success
#if defined GPS_SERIAL
/* insert user configuration here, if needed */
#elif defined GPS_I2C
/* insert user configuration here, if needed */
#endif
return rslt;
}
// store current GPS location data in struct
void gps_storelocation(gpsStatus_t *gps_store) {
if (gps.location.isUpdated() && gps.location.isValid() &&
(gps.location.age() < 1500)) {
gps_store->latitude = (int32_t)(gps.location.lat() * 1e6);
gps_store->longitude = (int32_t)(gps.location.lng() * 1e6);
gps_store->satellites = (uint8_t)gps.satellites.value();
gps_store->hdop = (uint16_t)gps.hdop.value();
gps_store->altitude = (int16_t)gps.altitude.meters();
}
}
// function to fetch current time from struct; note: this is costly
time_t fetch_gpsTime(uint16_t *msec) {
time_t time_sec = 0;
// poll NMEA $GPZDA sentence
#ifdef GPS_SERIAL
GPS_Serial.print(ZDA_Request);
// wait for gps NMEA answer
vTaskDelay(tx_Ticks(NMEA_FRAME_SIZE, GPS_SERIAL));
#elif defined GPS_I2C
Wire.print(ZDA_Request);
#endif
// did we get a current time?
if (gpstime.isUpdated() && gpstime.isValid()) {
tmElements_t tm;
String rawtime = gpstime.value();
uint32_t time_bcd = rawtime.toFloat() * 100;
uint32_t delay_ms =
gpstime.age() + nmea_txDelay_ms + NMEA_COMPENSATION_FACTOR;
uint8_t year =
CalendarYrToTm(gps.date.year()); // year offset from 1970 in microTime.h
ESP_LOGD(TAG, "time [bcd]: %u", time_bcd);
tm.Second = (time_bcd / 100) % 100; // second
tm.Minute = (time_bcd / 10000) % 100; // minute
tm.Hour = time_bcd / 1000000; // hour
tm.Day = gps.date.day(); // day
tm.Month = gps.date.month(); // month
tm.Year = year; // year
// add protocol delay to time with millisecond precision
time_sec = makeTime(tm) + delay_ms / 1000;
*msec = (delay_ms % 1000) ? delay_ms % 1000 : 0;
}
return timeIsValid(time_sec);
} // fetch_gpsTime()
time_t fetch_gpsTime(void) {
uint16_t msec;
return fetch_gpsTime(&msec);
}
// GPS serial feed FreeRTos Task
void gps_loop(void *pvParameters) {
configASSERT(((uint32_t)pvParameters) == 1); // FreeRTOS check
while (1) {
if (cfg.payloadmask & GPS_DATA) {
#ifdef GPS_SERIAL
// feed GPS decoder with serial NMEA data from GPS device
while (GPS_Serial.available()) {
gps.encode(GPS_Serial.read());
}
#elif defined GPS_I2C
Wire.requestFrom(GPS_ADDR, 32); // caution: this is a blocking call
while (Wire.available()) {
gps.encode(Wire.read());
delay(2); // 2ms delay according L76 datasheet
}
#endif
} // if
// show NMEA data in verbose mode, useful for debugging GPS
ESP_LOGV(TAG, "GPS NMEA data: passed %u / failed: %u / with fix: %u",
gps.passedChecksum(), gps.failedChecksum(),
gps.sentencesWithFix());
delay(2); // yield to CPU
} // end of infinite loop
} // gps_loop()
#endif // HAS_GPS