RE: current consumption for ble nrf52840

Vidar Berg — Thu, 24 Jul 2025 06:49:55 GMT

The main reason for the increase in current while in the connected state in the original case is likely that you were calling uart_init() in the connected event. Enabling UART reception raises the base current to ~0.61-1 mA as it forces system resources like the HF clock to stay on in sleep.

But I'm not sure why you are measuring 516 uA in the advertising state now. Edvin did not suggest any code changes relevant to this state.

RE: current consumption for ble nrf52840

NANDANI — Wed, 16 Jul 2025 09:44:35 GMT

After implementing the provided solution:

When BLE is not connected, the Power Profiler Kit shows:
- Average current: 516 µA
- Maximum current: 95.46 mA
When BLE is connected, the Power Profiler Kit shows:
- Average current: 1.44 mA
- Maximum current: 19 mA

RE: current consumption for ble nrf52840

Edvin — Wed, 11 Jun 2025 21:53:26 GMT

Hello,

[quote user="Tubald"]How do you measure the current consumption? I am trying to do this on my nrf52840 with a multimeter, but without any success.[/quote]

The challenge is that a BLE device will have very little current consumption most of the time, but then it will have large spikes, when the radio is being used, and for some periods where the CPU is being used. Most Multimeters may not sample quick enough to see these spikes, so it will give a very inaccurate measurement.

As NANDANI says, you can use the Power Profiler Kit (II) to measure an accurate current consumption, either on our DKs, or 3rd party devices. It is actually a very good tool for it's price. You can also use it as a logic analyzer for signals that aren't too fast.

Regarding your current consumption:

[quote user=""]When BLE is not connected, current consumption is ~30 µA.
But when BLE is connected, consumption increases by ~1 mA.[/quote]

From what I can tell from your main.c file, you are using an advertising interval of 1000ms, and a connection interval between 300ms and 400ms. The 300 and 400ms, however, is a desired connection interval. It is not guaranteed that you will actually achieve this. It depends on your central device, who has the final saying in connection parameters.

What you can do is to try to connect to your peripheral using nRF Connect for Desktop, and it's "Bluetooth Low Energy" app. It does require an extra DK, but it will accept any connection parameter change request that the peripheral requests. So when the central first connects, it will decide the connection interval. But after FIRST_CONN_PARAMS_UPDATE_DELAY (5 seconds in your case) the peripheral will request it's desired connection parameters, given it is outside your desired parameters (300ms and 400ms).

Do you see that the current consumption goes down after 5 seconds? What if you use the nRF Connect for Desktop -> Bluetooth Low Energy app?

If not, can you try adding this to your ble_evt_handler():

        case BLE_GAP_EVT_CONN_PARAM_UPDATE:
            uint16_t max_conn_int = p_ble_evt->evt.gap_evt.params.conn_param_update.conn_params.max_conn_interval;
            uint16_t min_conn_int = p_ble_evt->evt.gap_evt.params.conn_param_update.conn_params.min_conn_interval;
            NRF_LOG_INFO("connection parameters updated. max: %d, min: %d", max_conn_int, min_conn_int);
            break;
        case BLE_GAP_EVT_CONN_PARAM_UPDATE_REQUEST:
            uint16_t max_conn_int = p_ble_evt->evt.gap_evt.params.conn_param_update_request.conn_params.max_conn_interval;
            uint16_t min_conn_int = p_ble_evt->evt.gap_evt.params.conn_param_update_request.conn_params.min_conn_interval;
            NRF_LOG_INFO("Connection parameters update request. max: %d, min: %d", max_conn_int, min_conn_int);
            break;

You can also add this to the BLE_GAP_EVT_CONNECTED case:

        case BLE_GAP_EVT_CONNECTED:
            NRF_LOG_INFO("Connected");
            [...]
            uint16_t max_conn_int = p_ble_evt->evt.gap_evt.params.connected.conn_params.max_conn_interval;
            uint16_t min_conn_int = p_ble_evt->evt.gap_evt.params.connected.conn_params.min_conn_interval;
            NRF_LOG_INFO("connection parameters: max: %d, min: %d", max_conn_int, min_conn_int);
            break;

To see your initial connection parameters.

What do you see? Does the connection parameters update after the connection event?

Best regards,

Edvin

RE: current consumption for ble nrf52840

NANDANI — Mon, 09 Jun 2025 07:04:34 GMT

power profiler kit using measure current consumption.

RE: current consumption for ble nrf52840

Tubald — Mon, 09 Jun 2025 07:02:33 GMT

Hello,
Sorry for not knowing the answer to your question, but maybe you can help me answer mine.
How do you measure the current consumption? I am trying to do this on my nrf52840 with a multimeter, but without any success.

I would really appreciate if you could tell me how to do it.

Thank you