LG290P with Raspberry Pi

GPS/GNSS
1

I’m trying to use a LG290P with a Pi 3 through the USB interface. The Pi doesn’t seem to recognize the 290P.

Is there a driver that needs to be installed on the Pi?

2

The product page notes ‘only the UART interface is supported by the module’

I would just pass one of the UARTs Hardware Overview - SparkFun LG290P Quadband GNSS RTK Breakout Hookup Guide Tx & Rx to the Rx & Tx of the Pi, then listen to those pins

3

Thanks. Somehow I thought UART included USB.

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4

You might be able to use raspi-config and enable serial and see if something shows up over the usb (bc the LG290P has a UART-USB on it) but hardwiring to Rx/Tx will definitely work :wink:

5

What is the initial baud rate on the 290P? How does one change that?

6

Looks like 460800 Hardware Overview - SparkFun LG290P Quadband GNSS RTK Breakout Hookup Guide

You shouldn’t need to change the board’s baud; change the Pi’s
You may need drivers for CH342 for the Pi…not sure how drivers work for those

7

Using the UART pins on the PI works fine, ty.

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8

More an observation than a fix, but in deploying PyGPSClient on a Raspberry Pi 5 to monitor and configure an LG290P, I noticed that none of the UART ports are recognised automatically by the standard Python function used by PyGPSClient to detect comms ports ( serial.tools.list_ports.comports()), even after enabling the serial interface in raspi-config and making the recommended changes to the /boot/firmware/config.txt file:

dtoverlay=uart2
dtoverlay=uart3
dtoverlay=uart4

This would seem to suggest there’s something slightly unusual about Quectel’s UART implementation on the LG290P - I’ve not seen this behaviour on any other serial GNSS device with a Raspberry Pi 4 or 5.

PyGPSClient does, however, allow users to manually add a user-defined serial port e.g. \dev\ttyAMA0, and it then works fine. The default baud rate for all 3 UART ports is 460800.

Note that some cheaper UART-USB FTDI adapters don’t support this baud rate, at least not reliably.

9

@Planxty312 Are you using the sparkfun LG290P breakout board, or another? If you’re using the Sparkfun LG290P board - it is kind of unique in that the UART to USB chip on it shows up in linux as two different ports, but only one is connected to UART1 from the LG290P.

Make sure you are using the right one. On my system they come up as ttyACM0 and ttyACM1 - and for me ttyACM1 is the one with data, but that can change.

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