1. HW set up
1.1. Required tools
STLINK-V3PWR is a two-in-one standalone debugger probe and a source measurement unit (SMU) designed to synchronize code execution with a power consu32KHzmption of STM32 applications in real time. This tool is specifically adapted for power consumption optimization (patent pending). STLINK-V3PWR can be used as a standalone source measurement unit to supply power and measure the current consumption of the target application. The product keeps the output voltage constant during a fast current transient from a very low current to a high current.
STM32CubeMonitor-Power (STM32CubeMonPwr) enables developers to swiftly analyze the power/low‑power consumption of target boards, and optimize the energy efficiency of their applications. This software tool acquires power measurements through the STLINK-V3PWR probe.
1.2. X-NUCLEO-67W61M1 supply injection
As shown below in the X-NUCLEO-67W61M1 schematic, the 3V3 is down-converted by an LDO from the 5 V Arduino pin input. By default, VDDRF is supplied by the 3V3 via JP2 closed.
JP2 must be removed and STLINK_V3PWR must be connected as shown below. It supplies the 3.3 V directly and the supply current is monitored in real time.
The picture below shows where to physically connect the supply.
2. Wifi Measurement result example
The plot below depicts the current measurement done with the ST67W6X_CLI Application project using the wifi_scan command.
3. Bluetooth® LE Measurement
3.1. Bluetooth® LE with low-power setup
Bluetooth® LE protocol requires an accurate low-frequency clock to enable low-power scenarios which is not the case with the internal RC oscillator.
Please refer to 32.768 kHz clock activation on the NUCLEO-U575ZI-Q board section to see how to use the 32.768 kHz clock from a STM32U5 host platform.
In order to support low-power mode in Bluetooth® LE projects the following SW changes are also required.
File w6x_config.h:
/** NCP will go by default in low power mode when NCP is in idle mode */
#define W6X_POWER_SAVE_AUTO 1
/** NCP clock mode : 1: Internal RC oscillator, 2: External passive crystal, 3: External active crystal */
#define W6X_CLOCK_MODE 3
3.2. Bluetooth® LE Measurement result example
The plot below depicts the current measurement done with a BLE server project during advertising and after a connection with a Smartphone.
