This is the documentation for the latest (main) development branch of Zephyr. If you are looking for the documentation of previous releases, use the drop-down menu on the left and select the desired version.

Dragino NBSN95 NB-IoT Sensor Node


The Dragino NBSN95 NB-IoT Sensor Node for IoT allows users to develop applications with NB-IoT connectivity via the Quectel BC95-G. Dragino NBSN95 enables a wide diversity of applications by exploiting low-power communication, ARM® Cortex®-M0 core-based STM32L0 Series features.

This kit provides:

  • STM32L072CZ MCU

  • Quectel BC95-G NB-IoT

  • Expansion connectors:
    • PMOD

  • Li/SOCI2 Unchargable Battery

  • GPIOs exposed via screw terminals on the carrier board

  • Housing

Dragino NBSN95

More information about the board can be found at the Dragino NBSN95 website.


The STM32L072CZ SoC provides the following hardware IPs:

  • Ultra-low-power (down to 0.29 µA Standby mode and 93 uA/MHz run mode)

  • Core: ARM® 32-bit Cortex®-M0+ CPU, frequency up to 32 MHz

  • Clock Sources:

    • 1 to 32 MHz crystal oscillator

    • 32 kHz crystal oscillator for RTC (LSE)

    • Internal 16 MHz factory-trimmed RC ( ±1%)

    • Internal low-power 37 kHz RC ( ±5%)

    • Internal multispeed low-power 65 kHz to 4.2 MHz RC

  • RTC with HW calendar, alarms and calibration

  • Up to 24 capacitive sensing channels: support touchkey, linear and rotary touch sensors

  • 11x timers:

    • 2x 16-bit with up to 4 channels

    • 2x 16-bit with up to 2 channels

    • 1x 16-bit ultra-low-power timer

    • 1x SysTick

    • 1x RTC

    • 2x 16-bit basic for DAC

    • 2x watchdogs (independent/window)

  • Up to 84 fast I/Os, most 5 V-tolerant.

  • Memories

    • Up to 192 KB Flash, 2 banks read-while-write, proprietary code readout protection

    • Up to 20 KB of SRAM

    • External memory interface for static memories supporting SRAM, PSRAM, NOR and NAND memories

  • Rich analog peripherals (independent supply)

    • 1x 12-bit ADC 1.14 MSPS

    • 2x 12-bit DAC

    • 2x ultra-low-power comparators

  • 11x communication interfaces

    • USB OTG 2.0 full-speed, LPM and BCD

    • 3x I2C FM+(1 Mbit/s), SMBus/PMBus

    • 4x USARTs (ISO 7816, LIN, IrDA, modem)

    • 6x SPIs (4x SPIs with the Quad SPI)

  • 7-channel DMA controller

  • True random number generator

  • CRC calculation unit, 96-bit unique ID

  • Development support: serial wire debug (SWD), JTAG, Embedded Trace Macrocell™

More information about STM32L072CZ can be found here:

Supported Features

The Zephyr Dragino NBSN95 board configuration supports the following hardware features:






serial port-polling; serial port-interrupt







Other hardware features are not yet supported on this Zephyr port.

The default configuration can be found in the defconfig file: boards/dragino/nbsn95/dragino_nbsn95_defconfig

Connections and IOs

Dragino NBSN95 Board has GPIO controllers. These controllers are responsible for pin muxing, input/output, pull-up, etc.

Available pins:

For detailed information about available pins please refer to Dragino NBSN95 website.

Default Zephyr Peripheral Mapping:

  • UART_1_TX : PB6

  • UART_1_RX : PB7

  • UART_2_TX : PA2

  • UART_2_RX : PA3

System Clock

Dragino NBSN95 System Clock is at 32MHz,

Serial Port

Dragino NBSN95 board has 2 U(S)ARTs. The Zephyr console output is assigned to UART1. Default settings are 115200 8N1.

Programming and Debugging

Applications for the dragino_nbsn95 board configuration can be built and flashed in the usual way (see Building an Application and Run an Application for more details).


Dragino NBSN95 board requires an external debugger.

Flashing an application to Dragino NBSN95

Here is an example for the Hello World application.

Connect the Dragino NBSN95 to a STLinkV2 to your host computer using the USB port, then run a serial host program to connect with your board. For example:

$ minicom -D /dev/ttyACM0

Then build and flash the application:

# From the root of the zephyr repository
west build -b dragino_nbsn95 samples/hello_world
west flash

You should see the following message on the console:

$ Hello World! dragino_nbsn95


You can debug an application in the usual way. Here is an example for the Hello World application.

# From the root of the zephyr repository
west build -b dragino_nbsn95 samples/hello_world
west debug