ST B-L072Z-LRWAN1 Discovery kit


This Discovery kit features an all-in-one open module CMWX1ZZABZ-091 (by Murata). The module is powered by an STM32L072CZ and an SX1276 transceiver.

This kit provides:

  • CMWX1ZZABZ-091 LoRa* / Sigfox* module (Murata)

    • Embedded ultra-low-power STM32L072CZ Series MCUs, based on Arm* Cortex* -M0+ core, with 192 Kbytes of Flash memory, 20 Kbytes of RAM, 20 Kbytes of EEPROM
    • Frequency range: 860 MHz - 930 MHz
    • USB 2.0 FS
    • 4-channel,12-bit ADC, 2xDAC
    • 6-bit timers, LP-UART, I2C and SPI
    • Embedded SX1276 transceiver
    • LoRa* , FSK, GFSK, MSK, GMSK and OOK modulations (+ Sigfox* compatibility)
    • +14 dBm or +20 dBm selectable output power
    • 157 dB maximum link budget
    • Programmable bit rate up to 300 kbit/s
    • High sensitivity: down to -137 dBm
    • Bullet-proof front end: IIP3 = -12.5 dBm
    • 89 dB blocking immunity
    • Low Rx current of 10 mA, 200 nA register retention
    • Fully integrated synthesizer with a resolution of 61 Hz
    • Built-in bit synchronizer for clock recovery
    • Sync word recognition
    • Preamble detection
    • 127 dB+ dynamic range RSSI
  • SMA and U.FL RF interface connectors

  • Including 50 ohm SMA RF antenna

  • On-board ST-LINK/V2-1 supporting USB re-enumeration capability

  • USB ST-LINK functions:

  • Board power supply:

    • Through USB bus or external VIN/3.3 V supply voltage or batteries
  • 3xAAA-type-battery holder for standalone operation

  • 7 LEDs:

    • 4 general-purpose LEDs
    • A 5 V-power LED
    • An ST-LINK-communication LED
    • A fault-power LED
    • 2 push-buttons (user and reset)
  • Arduino* Uno V3 connectors


More information about the board can be found at the B-L072Z-LRWAN1 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 B-L072Z-LRWAN1 Discovery board configuration supports the following hardware features:

Interface Controller Driver/Component
UART on-chip serial port-polling; serial port-interrupt
PINMUX on-chip pinmux
I2C on-chip i2c
SPI on-chip spi
GPIO on-chip gpio

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

The default configuration can be found in the defconfig file: boards/arm/b_l072z_lrwan1/b_l072z_lrwan1_defconfig

Connections and IOs

B-L072Z-LRWAN1 Discovery kit 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 B-L072Z-LRWAN1 website.

Default Zephyr Peripheral Mapping:

  • UART_1_TX/RX: PA9/PA10 (Arduino Serial)
  • UART_2_TX/RX: PA2/PA3 (ST-Link Virtual COM Port)
  • SPI1 NSS/SCK/MISO/MOSI: PA4/PA5/PA6/PA7 (Semtech SX1276 LoRa* Transceiver)
  • SPI2 NSS/SCK/MISO/MOSI: PB12/PB13/PB14/PB15 (Arduino SPI)
  • I2C1 SCL/SDA : PB8/PB9 (Arduino I2C)

System Clock

B-L072Z-LRWAN1 Discovery board System Clock is at 32mhz.

Serial Port

B-L072Z-LRWAN1 Discovery board has 2 U(S)ARTs. The Zephyr console output is assigned to UART2. Default settings are 115200 8N1.

Programming and Debugging

Applications for the b_l072z_lrwan1 board configuration can be built and flashed in the usual way (see Build an Application and Run an Application for more details).


B-L072Z-LRWAN1 Discovery board includes an ST-LINK/V2-1 embedded debug tool interface. This interface is supported by the openocd version included in the Zephyr SDK since v0.9.2.

Flashing an application to B-L072Z-LRWAN1 Discovery board

Here is an example for the Hello World application.

Connect the B-L072Z-LRWAN1 Discovery board 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:

# On Linux/macOS
cd $ZEPHYR_BASE/samples/hello_world
mkdir build && cd build

# On Windows
cd %ZEPHYR_BASE%\samples\hello_world
mkdir build & cd build

# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=b_l072z_lrwan1 ..

# Now run ninja on the generated build system:
ninja flash

You should see the following message on the console:

$ Hello World! arm


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

# On Linux/macOS
cd $ZEPHYR_BASE/samples/hello_world
# If you already made a build directory (build) and ran cmake, just 'cd build' instead.
mkdir build && cd build

# On Windows
cd %ZEPHYR_BASE%\samples\hello_world
# If you already made a build directory (build) and ran cmake, just 'cd build' instead.
mkdir build & cd build

# If you already made a build directory (build) and ran cmake, just 'cd build' instead.

# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=b_l072z_lrwan1 ..

# Now run ninja on the generated build system:
ninja debug