nRF9160: AT monitor
The AT monitor sample demonstrates how to use the AT monitor library and define AT monitors to receive AT notifications from the Modem library.
The sample supports the following development kit:
When built for an
_ns build target, the sample is configured to compile and run as a non-secure application with Cortex-M Security Extensions enabled.
Therefore, it automatically includes Trusted Firmware-M that prepares the required peripherals and secure services to be available for the application.
The sample defines two AT monitors, one for network status notifications (
+CEREG) and one for received signal quality parameters notifications (
+CESQ) through the
The sample then subscribes to both notifications and switches the modem to function mode one to register to the network.
While the device is registering to the network, the sample uses one of the AT monitors to determine if the registration is complete and monitors the signal quality using the other monitor.
Once the device registers with the network, the sample reads the modem PSM mode status, enables it, and reads the PSM mode status again.
Building and running
This sample can be found under
samples/nrf9160/at_monitor in the nRF Connect SDK folder structure.
When built as firmware image for the
_ns build target, the 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).
To read more about CMSE, see Processing environments.
To build the sample with Visual Studio Code, follow the steps listed on the How to build an application page in the nRF Connect for VS Code extension documentation. See Building and programming an application for other building and programming scenarios and Testing and debugging an application for general information about testing and debugging in the nRF Connect SDK.
After programming the sample to your development kit, complete the following steps to test it:
Connect the kit to the computer using a USB cable. The kit is assigned a COM port (Windows) or ttyACM device (Linux), which is visible in the Device Manager.
Connect to the kit with a terminal emulator (for example, PuTTY). See How to connect with PuTTY for the required settings.
Power on or reset your nRF9160 DK.
Observe that the sample starts and connects to the LTE network, while displaying both the network registration status and signal quality during the process.
Observe that the sample displays the PSM status twice on the terminal, once when it is disabled, and once when it is enabled.
Observe that the sample completes with a message on the terminal.
The sample shows the following output:
AT Monitor sample started Subscribing to notifications Connecting to network Resuming link quality monitor for AT notifications Waiting for network Link quality: -61 dBm Network registration status: searching Link quality: -59 dBm Network registration status: home Network connection ready Pausing link quality monitor for AT notifications Reading PSM info... PSM: disabled Enabling PSM Reading PSM info... PSM: enabled Periodic TAU string: 00000110 Active time string: 00100001 Modem response: +CEREG: 1,1 OK Shutting down modem Network registration status: no network Bye
This sample uses the following nRF Connect SDK libraries:
It uses the following sdk-nrfxlib library:
In addition, it uses the following secure firmware component: