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Modem Callbacks

Overview

The Modem Callbacks sample demonstrates how to set up callbacks for Modem library initialization and shutdown calls, using the Modem library integration layer and how to set up a callback for changes to the modem functional mode using the LTE link control library.

The sample performs the following operations:

  1. Registers callbacks during compile time for modem initialization, functional mode changes, and shutdown using the NRF_MODEM_LIB_ON_INIT, NRF_MODEM_LIB_ON_CFUN and NRF_MODEM_LIB_ON_SHUTDOWN macros respectively.

  2. Initializes the Modem library.

  3. Changes functional mode using the lte_lc_func_mode_set() function in the LTE link control library

  4. Shuts down the Modem library.

This triggers the callbacks for on_modem_init(), on_cfun() and on_modem_shutdown() functions.

Requirements

Before you start, check that you have the required hardware and software:

  • 1x nRF9151 Connect Kit
  • 1x nano-SIM card with LTE-M or NB-IoT support
  • 1x U.FL cabled LTE-M/NB-IoT/NR+ Flexible Antenna (included in the box)
  • 1x USB-C Cable
  • A computer running macOS, Ubuntu, or Windows 10 or newer

Set up your board

  1. Insert the nano-SIM card into the nano-SIM card slot.
  2. Attach the U.FL cabled LTE-M/NB-IoT/NR+ Flexible Antenna.
  3. Connect the nRF9151 Connect Kit to the computer with a USB-C cable.

Building the sample

To build the sample, follow the instructions in Getting Started Guide to set up your preferred building environment.

Use the following steps to build the Modem Callbacks sample on the command line.

  1. Open a terminal window.

  2. Go to NCS-Project/nrf9151-connectkit repository cloned in the Getting Started Guide.

  3. Build the sample using the west build command, specifying the board (following the -b option) as nrf9151_connectkit/nrf9151/ns.

    west build -p always -b nrf9151_connectkit/nrf9151/ns samples/modem_callbacks

    The -p always option forces a pristine build, and is recommended for new users. Users may also use the -p auto option, which will use heuristics to determine if a pristine build is required, such as when building another sample.

    Note

    This sample has Cortex-M Security Extensions (CMSE) enabled and separates the firmware between Non-Secure Processing Environment (NSPE) and Secure Processing Environment (SPE). Because of this, it automatically includes the Trusted Firmware-M (TF-M).

  4. After building the sample successfully, the firmware with the name merged.hex can be found in the build directory.

Flashing the firmware

Set up your board before flashing the firmware. You can flash the sample using west flash:

west flash

Tip

In case you wonder, the west flash will execute the following command:

pyocd load --target nrf91 --frequency 4000000 build/merged.hex

Testing

After programming the sample, test it by performing the following steps:

  1. Open up a serial terminal, specifying the correct serial port that your computer uses to communicate with the nRF9151 SiP:

    1. Start PuTTY.

    2. Configure the correct serial port and click Open:

    Open up a terminal and run:

    screen <serial-port-name> 115200

    Open up a terminal and run:

    screen <serial-port-name> 115200

  2. Press the DFU/RST button to reset the nRF9151 SiP.

  3. Observe the output of the terminal. You should see the output, similar to what is shown in the following:

    Terminal
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    All pins have been configured as non-secure
Booting TF-M v2.1.0
[Sec Thread] Secure image initializing!
*** Booting nRF Connect SDK v2.9.99-98a5e50b9ac1 ***
*** Using Zephyr OS v3.7.99-693769a5c735 ***
Modem callbacks sample started
Initializing modem library
> Initialized with value 0
Connecting to network
> Functional mode has changed to 1
Shutting down modem library
> Shutting down
> Functional mode has changed to 0
Bye