Once you've gotten the GPS module tested with direct wiring, we can go forward and set it up for Soft Serial connection. The soft serial connection works by setting up a secondary UART on two pins (digital 7 and 8) so that the main UART is free for debugging & uploading sketches
Soft Serial connection works on Uno/Duemilanove/Diecimila Arduinos as well as Leonardos. It does not work on Mega as the Mega does not have Soft Serial support on pins 7 & 8

Next up, download the Adafruit GPS library. This library does a lot of the 'heavy lifting' required for receiving data from GPS modules, such as reading the steaming data in a background interrupt and auto-magically parsing it. This library can be downloaded from the Arduino library manager.

Open up the Arduino library manager:

Search for the Adafruit GPS library and install it

For Arduino UNO and other Atmega 328 boards: Due to limited memory, the shield_sdlog example will not work with the latest version of the library. If you want to log GPS messages on the UNO, you will need to install version 1.1.3 or earlier of the GPS library.

We also have a great tutorial on Arduino library installation at:

Open up the File→Examples→Adafruit_GPS→GPS_SoftwareSerial_EchoTest sketch and upload it to the Arduino. Then open up the serial monitor. This sketch simply reads data from the software serial port (pins 7&8) and outputs that to the hardware serial port connected to USB.

You can configure the output you see by commenting/uncommenting lines in the setup() procedure. For example, we can ask the GPS to send different sentences, and change how often it sends data. 10 Hz (10 times a second) is the max speed, and is a lot of data. You may not be able to output "all data" at that speed because the 9600 baud rate is not fast enough.

In general, we find that most projects only need the RMC and GGA NMEA's so you don't need ALLDATA unless you have some need to know satellite locations.

This guide was first published on Feb 18, 2013. It was last updated on Mar 08, 2024.

This page (Soft Serial Connect) was last updated on Mar 08, 2024.

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