STM32WBA65RI BLE Advertise with Standby Mode

[JPortilha]

Hello,

I am currently working with the NUCLEO-STM32WBA65RI. My main goal is to place the board in Standby mode and periodically wake it up to perform BLE advertising (as a Peripheral), while still allowing it to handle a possible connection request from another device.

So far, I have followed the "Standby with RTC" example to implement low-power operation. I would now like to integrate the BLE stack to enable advertising during the wake-up periods. The intended behavior is for the device to sleep for 1 minute, wake up via the RTC, perform advertising for a short duration, and then return to Standby mode.

From the documentation, I understand that the radio and Link Layer must be in deep sleep for Standby mode to be properly achieved. Could you provide some guidance on the correct way to ensure this state? Additionally, what happens if the radio is not in deep sleep when attempting to enter Standby mode?

Best regards,

[Imen.D]

Hello @JPortilha ,

To properly enter Standby mode on the STM32WBA, it is essential that the BLE Link Layer and radio are in deep sleep. This is achieved by ensuring there is no ongoing or scheduled radio activity and switching the Link Layer to deep-sleep mode, which is the lowest power state for the BLE hardware.

If the BLE Link Layer or radio is not in deep sleep when attempting to enter Standby, the Standby mode cannot be properly entered, as this is a strict requirement, and the system will not achieve the lowest power consumption state.

I recommend you the following resources and articles as guidance:

• "Standby mode" section in the RM0515 (page 312)
• AN5928: How to build a short range wireless application with STM32WBA MCUs
• STM32CubeWBA: Low-power management - stm32mcu

[JPortilha]

Hello, 

I have already read all those documents, I was in search of a code snippet that could help me. I have already looked at the BLE_HeartRate examples (with ThreadX and bare metal). On those examples, it seems to me that the standby mode is not completely reached as the current consumption in the low power mode is around 15uA. My goal was to put the system in the lowest consumption possible (in the nano Amps scale), with all the radio stack disabled. When the device wakes-up (very ocasioanlly), it should re-init all again and advertise. On those examples, it does not seem that the device makes a soft reset. Can you help me understand this?

BR. 

[JPortilha]

Would it be possible to combine the BLE Direction Finder example with standby mode? How does that example run on the NUCLEO-STM32WBA65RI Dev Kit that only has 1 antenna?