Stm32-WB55RG high power consumption between adv peaks

[edantoni96]

Describe the bug I'm migrating my project to Zephyr and tried to reach the same level of Power consumption as in the original project using only HAL and FREERTOS. In my original project I could see the power consumption between two advertising peaks reaching the lowest possible level at around 10uA. I saw an example for this feature in samples/boards/stm32/power_mgmt/stm32wb_ble but I haven't been able to achieve the lowest possible power consumption. I tried to build the example as it is but still couldn't manage to get the same result.

BLE CoProcessor Binary : stm32wb5x_BLE_HCILayer_fw.bin (V1.18.0)

My Observation CPU2 wakes up CPU1 from stop2 modes which is unlikely or CPU2 didn't go to STOP mode after advertising event.

To Reproduce Steps to reproduce the behavior:

1. flash the coprocessor binary using version 1.18.0
2. go to zephyrproject
3. west build -b nucleo_wb55rg samples/boards/stm32/power_mgmt/stm32wb_ble
4. flash the sample using west flash / stm32 cube programmer
5. Measure the power using stm32 power monitor

Expected behavior 37895

Impact The device cant reach expected power budget.

Environment (please complete the following information):

• OS: Linux, & Windows
• Toolchain Zephyr SDK v0.16.5
• Zephyr v3.6.0

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[whati001]

Hi All,

I am facing exactly the same problem, as already explained within my discord message. My goal is to replace the existing application build upon ST hal and FreeRTOS with Zephyr. Unfortunately, as @edantoni96 has mentioned the current consumption during advertisement phase is significantly higher because something does not release the resource during advertisement idle phase.

Just to illustrate my findings, which are exactly what is mentioned by @edantoni96: 1) Board: nucleo_wb55rg 2) Zephyr commit 5d054a7eb8fa7786e6459bf348e3ea1ff7208566 3) Zephyr example: samples/boards/stm32/power_mgmt/stm32wb_ble 3.1) Change BLE advertisement interval to (min) 500 ms and (max) 600 ms 4) ST BLE Stack: stm32wb5x_BLE_HCILayer_fw.bin (V1.18.0) on CPU2

As we can see in the screenshot above the power consumption statically increases once the ble host executes bt_le_adv_start and remains high until bt_le_adv_stop.

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The question for me is now, if the HCI ble stack of ST simply does not stop CPU2 or if there is something else wrong with the host implementation in zephyr. The current app implementation, with the current consumption, leverages the full ble stack of ST.

[erwango]

The question for me is now, if the HCI ble stack of ST simply does not stop CPU2 or if there is something else wrong with the host implementation in zephyr.

This is coming from Zephyr integration.

[whati001]

The question for me is now, if the HCI ble stack of ST simply does not stop CPU2 or if there is something else wrong with the host implementation in zephyr.

This is coming from Zephyr integration.

Nice that you already have a hint from where the issue comes from. If there is something I can support please let me know. Unfortunately, I am not an expert in zephyr's ble host but happy to help where I can so resolve this issue :)

[erwango]

Unfortunately, this is not high prio compared to others tasks. I'll make sure it won't be forgotten though and will keep you updated about the plan.

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[whati001]

@Erwango Any update here?

[erwango]

@erwango Any update here?

Unfortunately no.