sparkfun DEV-17272 Hook-Up Manual page 25

The things to look out for are a 980 milli-g Acceleration in Z - if your board is horizontal. That's gravity. You will also
see a reading of the Earth's magnetic field on one or more of the Magnetometer (Compass) axes, but the value
will depend on your local Angle Of Magnetic Declination and Inclination. (Strange but true: the strongest magnetic
field points downward into the ground in many places.)
Example 3: µSD Card
Example3 uses Bill Greiman's SdFat library to print a directory of all the files on your microSD card.
The usual restrictions apply: we recommend disconnecting the power to your Asset Tracker before removing or
inserting the µSD card. Removing the card while powered can cause data corruption.
Example 4: MAX17048 Fuel Gauge
Example4 demonstrates how to use the MAX17048 Fuel Gauge to read the battery charge status.
Example 5: Qwiic
Example5 demonstrates how to use the Qwiic bus to talk to an external sensor attached to the Qwiic connector.
The example assumes that you have a Qwiic Power Switch attached, but you can adapt the code to use
whichever Qwiic board you have available. The Qwiic I C bus is called Wire on the Asset Tracker.
Example 6: I/O Pins
Example6 demonstrates how to configure the D0, D1, A0, A1, PWM0 and PWM1 Input / Output pins.
Example 7: GNSS Antenna Power
Example7 is where we communicate with the SARA-R5 for the first time. The power for the active GNSS antenna
is controlled by the SARA GPIO2 pin. When the SARA is on and GPIO2 is high, the 3.3V antenna power is
enabled. We need to instruct the SARA to enable GPIO2 and set it high via the UART interface.
The example code calls
lifting for you. Those functions are defined in AssetTrackerPins.in and in turn call the SARA-R5 library:
assetTracker.setGpioMode(assetTracker.GPIO2, assetTracker.GPIO_OUTPUT, 1); // Enable
and
assetTracker.setGpioMode(assetTracker.GPIO2, assetTracker.GPIO_OUTPUT, 0); // Disable
There is no indicator LED to tell you if the antenna power is on. You can, if you wish, use a digital multimeter to
probe carefully on the center pin of the GNSS SMA connector. You will see voltage toggling between 3.3V and 0V.
Important! When probing the GNSS SMA connector be very careful to avoid static discharge. A grounding
strap is recommended to prevent damaging the antenna and board from static discharge.
This example demonstrates that serial communication is taking place between the Processor Board and the
SARA-R5.
Example 8: External SPI
enableGNSSAntennaPower();
2
and
disableGNSSAntennaPower();
which do the heavy