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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.
Remove JP2 and connect STLINK_V3PWR as shown below. STLINK_V3PWR supplies 3.3 V directly, and the supply current is monitored in real time. To measure the VDD_IO current, remove JP1 and connect STLINK_V3PWR in a similar way.
The picture below shows where to physically connect the supply.
2. Wifi Measurement result example
The plot below depicts the VDDRF 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 VDDRF current measurement done with a BLE server project during advertising and after a connection with a Smartphone.
