UART for Tiny RTK


I have a question regarding the UART hardware connection. From the last question/topic from Marcel

Tiny RTK GPS (NEO-M8P Rover): Use same UART for RTCM and NMEA?,

the TXD and RXD for both port A and B should be connected.

By referring to your wiring and schematic for the Tiny RTK GPS documentation, I tried to check the electrical connection test on both Tiny GPS RTK kit that I’ve. It seems that only the TXD (port A5 and B4) pins connected meanwhile the both RXD pins are not connected between each other. Is it actually a PCB mistake or is it on purpose?

Furthermore, from the documentation there is a switch on the side of Tiny RTK GPS board. What is the purpose of the switch? The Tiny RTK GPS that we recently got are however not featured with switch. (I assume the switch is maybe the updated version of the board).

Best regards, Z. Zulkifli


You should see a solder bridge on the Tiny module. With this option, you will be able to activate the rover or telem mode. What do you want to do with the system?

Hi Jerome,

Thank you very much for your reply. It is just some positioning system research we are doing right now.
I find this separate solder bridge is useful to give more flexibility on connecting device i.e. microcontroller. The question is just to make sure that if there is an event that both RXD pins need to be connected, then I know what needs to be done.

After all, thanks again!

Best regards, Z. Zulkifli

You have to connect the TX of your telemetry radio to the RX of the port A of the Tiny module. Then enable the solder bridge on the telemetry side.

I have two Tiny RTK GPS NEO-M8P devices that I ordered quite some time ago. When I ordered them, I specified one as a rover and one as a base. They do not have a switch on the side of the device. Unfortunately, I have mixed up the two modules, and I don’t know which is the rover or base. They look to be identical.

How can identify the rover or base? Secondly, I’d like to understand why someone would need to perform the soldering operation described above.

You can follow the docs here to configure and check the GPS.