Issue running GPS code

[atin121]

Super handy library, the LoRa stuff works great. Trying to read off the GPS, I am getting:

Archiving built core (caching) in: /var/folders/fs/yrrtd9hn7p1bsz8n_57_69cc0000gn/T/arduino_cache_893081/core/core_esp32_esp32_ttgo-lora32-v1_FlashFreq_80,UploadSpeed_921600,DebugLevel_none_279fa844f13a7dc74d194a5db99730eb.a arduino.ar(HardwareSerial.cpp.o):(.bss.Serial1+0x0): multiple definition of `Serial1' sketch/GPS.ino.cpp.o:(.bss.Serial1+0x0): first defined here collect2: error: ld returned 1 exit status exit status 1 Error compiling for board TTGO LoRa32-OLED V1.

I added the TinyGPS++ library to my Arduino IDE to get to this point. I'm a long time mobile dev doing my first dabbles into Arduino stuff so forgive me if this is a basic thing! Thanks

[atin121]

If I comment out the line "//HardwareSerial Serial1(1);" it runs, but I get no data from the GPS (all 0s).

[jcwren]

Try reversing the TXD and RXD pin numbers. My code was using the Espressif esp-idf platform instead of Arduino, but the pins numbers listed are backwards.

And if you're lucky, you won't have a counterfeit uBlox NEO-6M like my two do. It'll work as a GPS, but only with basic NMEA strings. You won't be able to use uBlox commands, or the NMEA PUBX commands.

[atin121]

Thanks @jcwren for the quick reply, sadly no luck. When I flip them(to 15, 12), after a few iterations I start seeing the 'check wiring' message. Any suggestions about further steps to troubleshoot?

I should note that I have the TTGO board without a OLED (unlike as indicated in my initial post), specifically: https://de.aliexpress.com/item/TTGO-T-Beam-ESP32-433-868-915Mhz-WiFi-wireless-Bluetooth-Module-ESP-32-GPS-NEO-6M/32875743018.html

[jcwren]

Sorry, no other ideas. Once I got the TXD and RXD straightened out, it started spitting out NMEA data at 9600 baud. The GPS is definitely on UART1. That's the same one I have, only through Banggood.

And if you have any GPS signal, the red LED should start blinking. It's the 1PPS output, and requires the GPS to have acquired enough satellites to get a time fix.

[atin121]

Solved! Being in the middle of an old building was the problem, once I was up on the roof I was good to go.

For future reference, the key was noting (as JCWren mentioned) that there are two status LEDs next to the NEO-6M chip, the blue one for GPS power and the red for GPS lock. This red LED should be blinking - if not, then no GPS fix.

[KommandorKeen]

Even simpler for diagnostic purposes just load a serial echo/passthrough and check out what is coming out. I had to comment out the Hardware Serial line too. But found pin 12 (as was written on the board) was the correct pin to receive info.

With serial passthrough I could use the unit as a gps input to QGIS.

[Xerxes3rd]

For anyone interested, here's a sample sketch that's basically a pass-through to the GPS. u-blox u-center works fine with it, and is able to enable/disable sentences, etc.

// Note these are opposite from the silk screen on the board
#define GPS_RX 12
#define GPS_TX 15

void setup() {
  Serial.begin(9600);
  Serial1.begin(9600, SERIAL_8N1, GPS_RX, GPS_TX);
}

void loop() {
  while (Serial1.available()) {
    Serial.write(Serial1.read());
  }
  while (Serial.available()) {
    Serial1.write(Serial.read());
  }
}

[lopoty]

My ttgo t-beam continues to has problems as the code cannot be compiled. What to do? The error is Archiving built core (caching) in: /var/folders/fs/yrrtd9hn7p1bsz8n_57_69cc0000gn/T/arduino_cache_893081/core/core_esp32_esp32_ttgo-lora32-v1_FlashFreq_80,UploadSpeed_921600,DebugLevel_none_279fa844f13a7dc74d194a5db99730eb.a arduino.ar(HardwareSerial.cpp.o):(.bss.Serial1+0x0): multiple definition of `Serial1' sketch/GPS.ino.cpp.o:(.bss.Serial1+0x0): first defined here collect2: error: ld returned 1 exit status exit status 1 Error compiling for board TTGO T-Beam

If I put a comment in the code Serial1.begin(115200, SERIAL_8N1, 12, 15); //17-TX 18-RX it doesnot have problems.