STM32WB Thread SED device high current consumption after 3 minutes of inactivity

[paul.uuu]

Hi there,

I'm using the STM32WB55 to build a ultra low power sensor. The low power is working very well on the M4 with my firmware but the M0 with the Thread MTD stack is giving back unexpected results.

Since the sensor can sleep for a while (also 10 minutes and also more) between samplings, I'm setting it as a SED by using the otLinkSetPollPeriod and the otThreadSetLinkMode to tell the radio to sleep and poll the parent every 5 minutes and it seemed to work.

During the consumption tests we noticed that while the M4 was still asleep, the M0 started an high consumption (~10mA) after 3 exact minutes of inactivity (no tx from us and poll period at 5 minutes). The high consumption stops after other 2 minutes (so, after a total of 5, as the poll period set).

I really don't know what's happening, am I missing something?

Thank you in advance for your help

Have a nice day

Paul

[Remi QUINTIN · Accepted solution]

We will start working on this item asap.

It could be linked to the fact that the SF timer (which is used on 802_15_4) is modulo 3 minutes…

[paul.uuu]

Hi Remi,

have you find anything on this subject?

We are still having this issue and now we are starting to be late on market...

I also repeated the test using the latest stack (MTD) and FUS from STM32Cube_FW_WB_V1.10.0 but the issue still remains.

I made few changes on the Thread_SED_Coap_Multicast example:

• changed poll period to 5 minutes
• disabled (commented) coap send task

The results are the same:

-> On startup and before the radio is connected to an FTD device the power consumption is around 11mA.

-> When the polling is set (5minutes) and rx is switched off with otThreadSetLinkMode, the power consumption arrive at 0.08mA

-> at minute 3 from startup the power raise to 1.9mA and it remains like this for 2 minutes

-> at minute 5 the power come back to 0.08mA

-> at minute 8 the power raise again to 1.9mA

-> at minute 10 the power goes back to 0.08mA

.... and so on....

Do you have any update for me?

Thank you

Best regards

Paolo

[paul.uuu]

Hi Remi,

I opened a ticket on the support, they found the same issue and even them say that could be related to the modulo 3 minutes SF timer.

I will proceed with the dedicated support so there is no need to go on here on the forum.

Thank you for your support

Best regards

Paolo