Disclaimer: I’m very much not an EE
I’m trying to connect my u-blox based GNSS board to the Navigator board via UART serial. I’ve tried many variations but cannot receive good data. When using a UART to USB adaptor connected directly to the Raspberry Pi the data comes through fine.
After analysing the signal with an oscilloscope considerable noise was apparent when the signal is low. This only happens when the UART is connected directly to the Navigator serial and not through the USB adaptor. Also a clean signal is observed when the GNSS TX line is not connected to the Navigator serial.
Noisy Signal - Blue = GNSS Vin, Yellow = GNSS Tx
Clean Signal - GNSS TX not connected to Navigator RX
GNSS Board: https://www.taoglas.com/datasheets/EL20.pdf
Wiring:
GNSS GND → Navigator -
GNSS Vin → Navigator +
GNSS Tx → Navigator Rx
GNSS Rx ->Navigator Tx
I have also tried:
- Powering the GNSS with a 3.2v power supply - Ensuring logic levels are 3.2v
- Attaching all grounds to the navigator power supply ground
- Switching TX and RX pins
- Passing everything through the GNSS to Navigator wiring loom before going into the UART to USB adaptor confirming the wiring loom works
- Other serial devices work on the same Navigator serial port
- Reading serial data with a python script, - should be NMEA but is garbled but fine with the USB adaptor.
I’m at a loss and any feedback/ help would be greatly appreciated.
Thanks in advance.