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I am trying to get a GNSS module to communicate with a raspberry pi serially. I was attempting to set this up with an ESP module but I don't think it will work, or at least I am missing something. In the past I have used RPi break-out boards for GNSS with success. But this time I need to put the module on a PCB. The good thing about the breakout boards is that they don't require much additional circuitry, if any. But some of the PCB surface mount modules require lots of circuitry and I am trying to avoid this.

I think I've found a U-blox module that can be mounted to a PCB and then just connected to an antenna, ground, Vcc, and serial interface. Which is similar to the requirements of the breakout boards. The module is U-blox Max-8 datasheet

The datasheet mentions connections to an external crystal oscillator and RF in (antenna). I am sure there is some circuitry around the antenna, but I am not sure how to design this. Also there is a time pulse output.

Below I attached the footprint and block diagram of the GNSS module. As I thought it might help.

Will my set-up be okay if I just connect Vcc, GND, antenna, and UART to the Pi?

block diagram footprint

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  • \$\begingroup\$ You talk about GNSS, but the module you reference is for Bluetooth LE. You might want to resolve this. \$\endgroup\$
    – Kartman
    Mar 17, 2021 at 17:46
  • \$\begingroup\$ looks like you are correct there are lots of Ublox modules and I must've mixed them up \$\endgroup\$
    – Feynman137
    Mar 17, 2021 at 17:49
  • \$\begingroup\$ I will edit the question \$\endgroup\$
    – Feynman137
    Mar 17, 2021 at 17:50
  • \$\begingroup\$ Edited the question to contain Max8 module instead of NINA-B410 \$\endgroup\$
    – Feynman137
    Mar 17, 2021 at 18:06

1 Answer 1

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That should be all you need, make sure the max current from the nrF52833 can be supported by the PI. The GPS antenna will probably require an impedance controlled transmission line (the trace will need to be calculated, check the datasheet to see if it's 50Ω or some other value (75Ω maybe), then calculate the trace width with an online calculator. Four layer boards work better with a signal layer with a ground plane just underneath. It also helps to keep the trace to the U.fl short).

Other than that make sure you have your TX's and Rx's for the uarts right here is a pinout for the UARTS:

https://raspberrypi.stackexchange.com/questions/104464/where-are-the-uarts-on-the-raspberry-pi-4

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  • \$\begingroup\$ I apologize I have edited the original question due to an error mentioned in the comments. A lot of the info from the original post has changed. Hope I did not waste your time! \$\endgroup\$
    – Feynman137
    Mar 17, 2021 at 18:05
  • \$\begingroup\$ As to what you need to do on the pcb - that's in the module's documentation. For the most part it is simply mounting the module, wiring up the power and serial connections etc. Where it gets tricky, is RF interference from the RasPi drowning out the GPS/GNSS signal. Look inside an old TomTom and see the lengths they went to in order to shield the receiver from the RF noise generated locally. The Pi is going to generate more noise as it is a faster processor. You might want to consider an off the shelf usb GNSS receiver - might be cheaper, easier and more reliable. \$\endgroup\$
    – Kartman
    Mar 18, 2021 at 12:09
  • \$\begingroup\$ @Feynman137 nothing has changed, it's the same as long as your still using a uart \$\endgroup\$
    – Voltage Spike ♦
    Mar 18, 2021 at 13:24
  • \$\begingroup\$ Thanks guys, that's good to hear as I am still planning to use UART. This board doesn't have an IPEX connector for the RFin line though. Is that pretty easy to add? \$\endgroup\$
    – Feynman137
    Mar 18, 2021 at 13:33
  • \$\begingroup\$ meta.stackexchange.com/questions/126180/… \$\endgroup\$
    – Voltage Spike ♦
    Mar 18, 2021 at 15:07

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