BLE mesh device entering sleep / low power mode in nRF Connect SDK

RE: BLE mesh device entering sleep / low power mode in nRF Connect SDK

usmanmehmood55 — Tue, 30 May 2023 06:51:41 GMT

You can have a time based wake-up or a GPIO based wake-up. There can be more but these two are the only ones I have tested.

To setup the controller for sleep, you can have something like this

void set_pm_state()
{
    struct pm_state_info info =
    {
        .exit_latency_us  = 0,
        .min_residency_us = 0,
        .state            = PM_STATE_SUSPEND_TO_RAM,
        .substate_id      = 0,
    };
    pm_state_force(CPU_ID, &info);
}

Then whenever you have to put it to sleep, you can have this code in a function

void pre_sleep()
{
    const struct device *cons = device_get_binding(CONSOLE_LABEL); // get UART device
    pm_device_action_run(cons, PM_DEVICE_ACTION_SUSPEND);          // turn off UART
    bt_mesh_prov_disable(BT_MESH_PROV_GATT | BT_MESH_PROV_ADV);    // disabling provisioning bearer
    bt_mesh_suspend();                                             // turn off mesh
}

For sleep, use

k_sleep(milliseconds) // for specified time
k_sleep(K_FOREVER)    // for sleeping without a timeout

And then after waking up

void post_sleep()
{
    bt_mesh_resume();                                              // turn on mesh
    bt_mesh_prov_enable(BT_MESH_PROV_GATT | BT_MESH_PROV_ADV);     // enabling provisioning bearer
    const struct device *cons = device_get_binding(CONSOLE_LABEL); // get UART device
    pm_device_action_run(cons, PM_DEVICE_ACTION_RESUME);           // turn off UART
}

Hope this helps. 🙂

RE: BLE mesh device entering sleep / low power mode in nRF Connect SDK

Dker19 — Tue, 30 May 2023 06:41:26 GMT

usmanmehmood55 Okay, So how will it will be wakeup from that state? any specific code is required for that?

RE: BLE mesh device entering sleep / low power mode in nRF Connect SDK

usmanmehmood55 — Tue, 30 May 2023 06:33:52 GMT

The code that I provided in the question is in fact using PM_STATE_SUSPEND_TO_RAM, so just copy-paste it.

RE: BLE mesh device entering sleep / low power mode in nRF Connect SDK

Dker19 — Tue, 30 May 2023 05:39:25 GMT

usmanmehmood55 Thanks for reply!!

Do you have some sample code by using PM_STATE_SUSPEND_TO_RAM, PM_STATE_SUSPEND_TO_DISK? I don't want to use PM_STATE_STANDBY.

Can you please guide me here? I am working on the nrf5340dk board.

RE: BLE mesh device entering sleep / low power mode in nRF Connect SDK

usmanmehmood55 — Mon, 29 May 2023 17:25:40 GMT

[quote userid="125979" url="~/f/nordic-q-a/91720/ble-mesh-device-entering-sleep-low-power-mode-in-nrf-connect-sdk/428005"]Can you please enlighten why there are different modes and When to use them? like, PM_STATE_RUNTIME_IDLE, PM_STATE_SUSPEND_TO_IDLE, PM_STATE_STANDBY and [/quote]

I'm not really sure about the other states. From what I remember, PM_STATE_SUSPEND_TO_RAM, PM_STATE_SUSPEND_TO_DISK, and PM_STATE_SOFT_OFF had the same power consumption during sleep mode for the nRF52832. For other controllers I don't know.

Not to mention I measured these 9 months ago, so any updates in the SDK might have changed the power consumption or the three modes might not be the same anymore.

[quote userid="125979" url="~/f/nordic-q-a/91720/ble-mesh-device-entering-sleep-low-power-mode-in-nrf-connect-sdk/428005"]Also is there any best state other than PM_STATE_SOFT_OFF which help my device to save more power without losing its context?[/quote]

I don't think so.

[quote userid="125979" url="~/f/nordic-q-a/91720/ble-mesh-device-entering-sleep-low-power-mode-in-nrf-connect-sdk/428005"]Do I just need to disable/suspend the resources that are taking more power, this will save the power consumption of the battery. CPU will automatically go into sleep mode?[/quote]

Not a 100% sure about this either, but from what I noticed, if no active thread is running (or if every thread is performing `k_sleep(...)` and the appropriate power management mode is selected, the CPU will be in sleep mode.

RE: BLE mesh device entering sleep / low power mode in nRF Connect SDK

Dker19 — Mon, 29 May 2023 16:44:28 GMT

usmanmehmood55

I required the device should be run in low power mode when there is no work to do. so I gone through the state.h and found that there are different states. So I choose PM_STATE_RUNTIME_IDLE or PM_STATE_SUSPEND_TO_IDLE so just curious like if I select one of them then on some event how to wakeup the device to a normal state.

Also is there any best state other than PM_STATE_SOFT_OFF which help my device to save more power without losing its context?

Do I just need to disable/suspend the resources that are taking more power, this will save the power consumption of the battery. CPU will automatically go into sleep mode?

Can you please enlighten why there are different modes and When to use them? like, PM_STATE_RUNTIME_IDLE, PM_STATE_SUSPEND_TO_IDLE, PM_STATE_STANDBY and

PM_STATE_SUSPEND_TO_RAM.
Also how to use them?

Do I need any power state to set other than PM_STATE_SOFT_OFF?

RE: BLE mesh device entering sleep / low power mode in nRF Connect SDK

Joakim Jakobsen — Tue, 04 Oct 2022 12:23:09 GMT

Thank you for sharing the solution.

Br,
Joakim

RE: BLE mesh device entering sleep / low power mode in nRF Connect SDK

usmanmehmood55 — Tue, 04 Oct 2022 12:12:40 GMT

Hi Joakim Jakobsen

I actually did find the solution to this. I achieved it by first turning off the UART, then provisioning bearers, and then mesh.

const struct device *cons = device_get_binding(CONSOLE_LABEL); // get UART device
pm_device_action_run(cons, PM_DEVICE_ACTION_SUSPEND);          // turn off UART
bt_mesh_prov_disable(BT_MESH_PROV_GATT | BT_MESH_PROV_ADV);    // disabling provisioning bearer
bt_mesh_suspend();                                             // turn off mesh

And then turn it back on using the opposite statements to these. Works like a charm.

RE: BLE mesh device entering sleep / low power mode in nRF Connect SDK

Joakim Jakobsen — Thu, 29 Sep 2022 18:50:14 GMT

Hi.

I apologize that this was left unanswered.

Do you still need assistance on this? Or did you find the answer to your questions?

Br,
Joakim