LTE GNSS Breakout - SARA-R5 Hookup Guide

Contributors: El Duderino, PaulZC
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This section outlines a few troubleshooting tips and common snags when using the LTE GNSS Breakout - SARA-R5.

LTE Network Availability

The SARA-R5 supports LTE-M and NB-IoT data communication for multi-regional use. Please check the LTE signal availability for your area before purchasing a SARA-R5 product and selecting an LTE service provider / operator.

Data Connectivity

When working through the data connectivity examples, it is important that you run examples 13, 14 and 17 in order, before moving on to example 18 or 19. Each example builds on the last and together they configure the SARA’s data connection correctly.

TP (1PPS) Pin and LED

At the time of writing, we are shipping the SARA-R5 on the Asset Tracker with firmware version 02.06 on it. 02.06 contains a feature (which is just a polite name for a bug!) which means the 1 Pulse-Per-Second from the GNSS does work, but the pulse is only ~3 microseconds wide and cannot be adjusted. Handy huh? u-blox are aware of this - in fact we told them about it - and a fix is coming but they haven’t added it yet. We will keep an eye out for it and update this section once the fix is released.

Just to complicate matters, 3 microseconds is too short for the buffer FET and LED connected to the timing pulse to respond. So, we regret that you cannot currently use the TP PTH. We will share the fix with you as soon as we have it.

NB/IoT Compatibility

The SparkFun LTE GNSS Breakout - SARA-R5 uses the "00B" product version of the SARA-R5 module (specifically the SARA-R510M8S-00B-00). LTE NB-IoT Radio Access Technology, and the LTE FDD bands: 66, 71, 85 are not supported by this version.

Arduino Debug Messages

If you run into any trouble using one of the Arduino examples, uncomment this line:


This enables serial debugging to print out the full debug report from AT commands sent via functions in the library. Read through the data and search for matching error codes in Appendix A of the AT Command Reference manual to decipher the code.

General Troubleshooting Help