1. NUCLEO-WL33CC boards
The STM32WL3x Nucleo-64 boards based on the MB1801 mezzanine board and MB2029 MCU RF board (NUCLEO-WL33CC1 and NUCLEO-WL33CC2 order codes) embed the STM32WL33CCV6 sub-GHz application processor. This high‑performance and low‑power application processor can operate in 433, 868, and 915 MHz bands.
The boards are defined in two product variants with dedicated front ends tuned for specific frequency bands.
| Order code | Board references | Target STM32 | Differentiating feature |
|---|---|---|---|
| NUCLEO-WL33CC1 |
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STM32WL33CCV6 | Front end optimized for 826‑958 MHz high band at 16 dBm |
| NUCLEO-WL33CC2 |
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Front end optimized for 413‑479 MHz high band at 16 dBm |
These Nucleo-64 boards are based on the STM32WL33CCV6 device.
The ARDUINO® Uno V3 connectivity support and the ST morpho headers provide an easy means of expanding the functionality of the STM32 Nucleo open-development platform with a wide choice of specialized shields.
The STM32WL3x Nucleo-64 boards come with a dedicated software package, HAL library, and various packaged software examples available with the STM32CubeWL3 MCU Package.
For more information on the NUCLEO-WL33CC board, refer to the product user manual (UM3416).
2. Boards and ST-LINK USB cable connections
For the MB1801 board:
- JP2 must be ON; JP1 must be set to 5V_STLK [1-2].
- Make sure that the SW1 switch is set to the 3V3 power supply (blue arrow - default switch in position [1-2]). Refer to section 7.1.5 of UM3418 for further details.
The different SW1 positions on the MB1801 board:
- Position [1-2]: this is the default position; the voltage source is U4 LDO, providing 3.3 V.
- Position [3-2]: the external sources can be applied to VEXT on CN10, ST morpho 5VEXT, or ARDUINO® VIN. The externally applied voltages must be in the range of the STM32WL33CC supply: 1.7 to 3.6 V. Refer to the solder bridge configurations of SB21, SB22, and SB23 for the specific use-case.
3. Connecting to STM32WL33CC while the chipset is inaccessible
In some application use-cases (such as the redefinition of SWD I/Os or an application loop) or if the application is using a low-power mode, it may no longer be able to access the STM32WL33CC chipset (even when using the STM32CubeProgrammer hot-plug mode). This might be due to the SWD I/O pins being unavailable in low-power modes.
To regain access to the STM32WL33CC chipset, jump to the preprogrammed bootloader. Then, use STM32CubeProgrammer or another programming tool or IDE to program or debug the chipset again.
3.1. Jumping to the bootloader with NUCLEO-WL33CC (Boot0)
The NUCLEO-WL33CCx board has a preprogrammed bootloader supporting the UART protocol with automatic baud rate detection. The main features of the embedded bootloader are:
- Automatic baud rate detection up to 1 Mbit/s
- Flash memory mass and section erase
- Flash memory programming
- Flash memory readout protection enable/disable.
The preprogrammed bootloader is an application, which is stored in the internal ROM by STMicroelectronics during manufacturing. This application allows for upgrading the flash memory device with a user application using a serial communication channel (UART).
The bootloader is activated by forcing PA10 high during hardware reset; otherwise, the application stored in the flash memory is launched.
NUCLEO-WL33CCx has two possibilities to force PA10 high:
- Soldering an SB resistor on the R1 footprint of the MCU RF board. This is not ideal, because STM32WL33CC does not boot from the internal flash memory until the SB is OFF.
- Inserting a jumper between pins 5-7 of the ST morpho CN3 connector, as shown in the image below.
| NUCLEO-WL33CC Boot0 jumper location |
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4. Power consumption measurement setup
Accurately measuring power consumption is essential for optimizing the performance and efficiency of an application. The NUCLEO-WL33CC evaluation kit offers a simple way to measure power consumption.
This setup can be used to measure power consumption for low-power modes (down to a few µA) or measuring RF MCU consumption when using RF (Rx or Tx, in mA).
For the following step, use STLINK-V3PWR or another power analyzer.
- Connect the GND of the measuring tool to the GND connector (CN12 or CN13) on the MB1801 board.
- Remove the JP2 jumper on the MB1801 board
- Connect VDD (from the external supply, like STLINK-V3PWR) to JP2-[2].
| NUCLEO-WL33CC dynamic power setup with external power supply |
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