BLE central application and low power

[Aurélien f]

Posted on October 18, 2017 at 10:58

Hello,

I'm pretty new to BLE devices. I intend to develop a BLE central application device that needs to run in low power most of the time. This central device will be paired with some other slave devices arround. My slaves will send data when it is needed. My question is the following and regards the central application device : is it possible to combine a BLE central application device and ultra low power, that is to say, is it possible to wake up my device when there is data to listen ? Or do i need to manually set my device in RX mode and wait for data coming from my slaves ?

If you have any ideas, don't hesitate to share your thoughts :)

Regards,

Aurélien

[Antonio Vilei]

Posted on October 19, 2017 at 10:33

Hi Aurélien,

please take a look at the SampleApp_DMA_LowPower project in the

http://www.st.com/content/st_com/en/products/embedded-software/mcus-embedded-software/stm32-embedded-software/stm32cube-embedded-software-expansion/x-cube-ble1.html

SW package.

To test it you need two STM32 Nucleo boards with their respective BlueNRG-MS STM32 expansion boards. One board will be configured as Peripheral role, while the other will be configured as Central role.

After connection has been established, by pressing the USER button on one board,the micro on the other one gets toggled from RUN to STOP mode and viceversa.

This example is highly optimized and shows how to get very low power consumption while still being able to react to BLE events.

Best regards,

Antonio

[Aurélien f]

Posted on October 19, 2017 at 15:18

Hi,

Thank you very much for your reply

Do you think with nucleo l073 it is possible because i have already several of them !

Is this expansion board could be ok to start : 

http://www.st.com/en/ecosystems/x-nucleo-idb05a1.html

 

What you present is exactly what i want, my central application will need to be in ultra low power but still reactive. On this central application device, I would like to be under 50uA during a kind of idle state but still listening my slaves, are my expection realistic ?

Best regards,

Aurélien

[Antonio Vilei]

Posted on October 19, 2017 at 15:51

Yes, I confirm that you can use the X-NUCLEO-IDB05A1 expansion board for Bluetooth Low Energy.

The example that I mentioned earlier has been tested with the NUCLEO-L053R8 board. As both boards are based on STM32L0, I think it should work fine with NUCLEO-L073RZ, too (even if it has not been tested on that board). Please take into account that you won't be able to get full advantage of your STM32L073RZ functionalities because the project has been configured for STM32L053R8 (which has less flash and RAM than yours).

As for power consumption, your expectation to have less than 50 ua  and still be able to react to BLE events is absolutely realistic. The longer you'll stay in low power mode, the lower the current value. If you send data infrequently (less than once per second), it will be even lower than that!

Best regards,

Antonio

[Aurélien f]

Posted on October 19, 2017 at 16:17

Thank you very for all the shared information. I will order two expansion boards.

I'm eager to start working on them.

Thx again