mesh_stack_init and Low Power

[Jerome ML]

Hello,

I'm working with the nRF5 SDK for Mesh v4.2.0.

During the init phase, I call the function mesh_stack_init()

After doing so, the consumption is on average 2.8 mA, even when doing :

    for (;;)
    {
        nrf_pwr_mgmt_run();
    }

And the MCU is never in idle state.

How to desactivate all the functions initialized by mesh_stack_init() in order to put the MCU in low power state ?

Thank you.

[Hung Bui]

Hi Jerome, 
When you enable mesh stack the radio will be active and stay in RX mode all the time. 
To achieve low power you need to disable the stack. 
Please have a look here: https://devzone.nordicsemi.com/f/nordic-q-a/57450/reliably-disabling-mesh-stack-quickly-for-low-power

[Jerome ML]

Thank you for your answer.

I tried this, and also to disable everything that I could, but it doesn't work.

PS : I made a lot of research and tests before posting my question, and I wouldn't have posted it if there was a publicly available and functionnal answer.

[Hung Bui]

Ok if you have done that and the current consumption still high, I suspect the high current was from something else. 

Have you made sure you power reset the chip before you do the measurement ? After flashing the chip will remain in debug mode hence the CPU will stay awake regardless what you do. A power reset needed. 

[Jerome ML]

The chip is not in debug mode. If I don't call the function mesh_stack_init(), the average power consumption is 2.3 µA.

I did what you suggested :

uint32_t retval = proxy_stop();

if (retval == NRF_SUCCESS)

{

retval = nrf_mesh_disable();

}

And I still have an average power consumption of 2.8 mA.

The INTENSET registers give me :

<t:      14010>, main.c,  410, Peripherals enabled:
<t:      14013>, main.c,  436,   RTC1:   	0x10002
<t:      14016>, main.c,  460,   RNG:    	0x1
<t:      14019>, main.c,  475,   MWU:    	0x1000001

So, it seems that the stack is not disabled.

I didn't find any example that disables the mesh stack. If you have one, I'm interested.

[Hung Bui]

Hi,

I added this:

 case 2:
        {
          uint32_t retval = proxy_stop();

          if (retval == NRF_SUCCESS)

          {

              retval = nrf_mesh_disable();
              if (retval != NRF_SUCCESS) 
              {
                  __LOG(LOG_SRC_APP, LOG_LEVEL_INFO, "error = %d \n",retval);
              }


          }
        break;
        }
        case 3:
        {
          retval = proxy_enable();
          if (retval == NRF_SUCCESS)
          {
              retval = proxy_start();
          }
          if (retval == NRF_SUCCESS)
          {
              retval = nrf_mesh_enable();
          }
           if (retval != NRF_SUCCESS)
           {
            __LOG(LOG_SRC_APP, LOG_LEVEL_INFO, "error = %d \n",retval);
            }
          break;

        }

Into button_event_handler() in light_switch server in SDK v4.2 and I can see when I press button 2 on nRF52832 DK the current dropped down to a few uA. And pressing button 3 will wake it up again (up to 12mA). 
(There is an issue when enabling it when it not provisioned that I'm looking into, but I guess it's not relevant to this thread)

Please make sure you don't use RTT log when you measure the current, it would keep the CPU awake. 
I attached the hex file here in case you need for testing. 

5001.light_switch_server_nrf52832_xxAA_s132_7.0.1.hex

[Jerome ML]

I did what you said, once more, and it still doesn't work.

I also added in the callback of the NRF_MESH_EVT_DISABLED event  :

mesh_adv_stop();
scanner_disable();

Some timer is still running and wakes up the MCU.

Try to do something like this in your own code, and tell me if the LED blinks :

for (;;)
{
    nrf_pwr_mgmt_run();
    nrf_gpio_pin_toggle(LED_1);
    nrf_delay_ms(100);
}

How to be sure that the RTT log is not working ?