GPS serial communication fails

[realhik]

I have tested the T-Impulse and got GPS and LoRaWAN working for TTN.

However, since a few days I could no longer get a GPS fix. Today, I have found out that the serial communication to the GNSS stopped working. Or to be more precise: all GPS_WaitAck("...");commands are no longer answered. All other peripherals work as expected. I used the original code with an Serial.println(ack); statement after ack = gpsPort.readStringUntil('\n') in GPS_Waitack();.

Any ideas how this can be fixed?

Thanks
Thorsten

[realhik]

Could the problem possibly be due to missing 1.8V, so that the GNSS has no supply voltage? How can this be checked?

[realhik]

LiLyGo support via Aliexpress told mit to compile and upload GPStest from the examples. Here is the result:

GPS Each test
Never try to send @FER, it clears GPS firmware!!
Never try to send @FER, it clears GPS firmware!!
Never try to send @FER, it clears GPS firmware!!
@GSTP  send time out
@BSSL 0x2EF send time out
@GSOP 1 1000 0 send time out
@GNS 0x03 send time out
@GSR  send time out
millis[8211]
millis[8712]
millis[9213]
millis[9714]
millis[10215]

and so on

[simkard69]

Here is my initialization sequency before trying to gather data from GPS serial port on STM32 :

PIN DEFINITIONS
// POWER / CHARGE / BATTERY
#define PIN_PWR_1_8v PB0
// GPS (CXD5603GF)
#define PIN_GPS_PWR PA3
#define PIN_GPS_EN PC6
#define PIN_GPS_1PPS PB5
#define PIN_GPS_RST PB2
#define PIN_GPS_TX PC10
#define PIN_GPS_RX PC11
#define GPS_BAUDRATE 115200

PIN INITIALIZATIONS
// GPS
pinMode(PIN_PWR_1_8v, OUTPUT); // PIN : POWERSWITCH > +1.8v power supply
pinMode(PIN_GPS_PWR, OUTPUT); // PIN : POWERSWITCH > GPS power supply (from +1.8v)
pinMode(PIN_GPS_EN, OUTPUT); // PIN : GPS > level shifter
pinMode(PIN_GPS_RST, GPIO_PULLUP); // PIN : GPS > reset (+ PULLUP)
digitalWrite(PIN_PWR_1_8v, HIGH); // Enable +1.8v power switch
digitalWrite(PIN_GPS_PWR, HIGH); // Enable GPS power switch (from +1.8v)

PRINT GPS SERIAL DATA ON SERIAL FOR USB DEBUGGING
while (gpsPort.available()){ Serial.write(gpsPort.read()); } // GPS data >>> SERIAL port

Hope that helps :)

[Litosaragon]

Same problem here, any update?

[pmoncks]

I'm also facing the same issue. Any solution? I Have T-Impulse wristband k200!

[Litosaragon]

If someone have any update about this issue, please write here in order to have all the solution ASAP