nrf52832 power consumption when disabling Twi driver (i2c)

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Luca Nisti — Tue, 21 Apr 2026 15:05:09 GMT

Håkon I think I've found the reason of the power consumption.

The hfclock need to be released. I though once no peripheral was using it, it was suspended but I was wrong.

Calling the nrf_drv_clock_hfclk_release when going to sleep fix the issue.

Thank you for your support.

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Luca Nisti — Tue, 21 Apr 2026 14:34:55 GMT

I can confirm there is no changes in power consumption, compared to the 2 cases above.

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Håkon Alseth — Tue, 21 Apr 2026 14:18:00 GMT

Hi,

[quote user="Luca Nisti"]Register checked is CLOCK->HFCLKRUN[/quote]

This shows only if the task has been triggered:

https://docs.nordicsemi.com/bundle/ps_nrf52832/page/clock.html#d910e3076

Which it will, as the SoftDevice will use the external HFXO (start and stop when finished), as the radio is unable to run on the HF_INT (which has % tolerance)

Can you please test with setting NRF_LOG_ENABLED to '0' and see if this has any impact?

Kind regards,

Håkon

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Luca Nisti — Tue, 21 Apr 2026 13:59:35 GMT

Hi Håkon Alseth .

I can confirm the high frequency clock is still running when the i2c is configured and disabled when firmware goes to sleep mode.

If the i2c is not initialized at all the high speed clock is off when in sleep mode.

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Luca Nisti — Tue, 21 Apr 2026 12:48:04 GMT

Here the file.

The NRF_LOG_ENABLED is set to 1 but module is not initialized at boot.

How does it explain the consumption when the i2c is initialized or not initialized?

devzone.nordicsemi.com/.../4274.sdk_5F00_config.h

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Håkon Alseth — Tue, 21 Apr 2026 12:15:19 GMT

Hi,

[quote user="Luca Nisti"]1. We measured the board consumption removing the mcu from the pcb, plus it is consistent with calculation done by the hw engineer.[/quote][quote user="Luca Nisti"]The results are consistent with different boards.[/quote]

Thank you for confirming.

[quote user="Luca Nisti"]2. I checked the SDA and SCL pin status during the sleep mode and they are set correctly to save power[/quote]

Good to hear.

[quote user="Luca Nisti"]3. Attached the sdk config file. I can confirm we are using the NRF_TWIM and TWI0_USE_EASY_DMA and TWI1_USE_EASY_DMA[/quote]

It looks like you have forgotten to attach the .h file?

Is the log module disabled? Should be sdk_config.h::#define NRF_LOG_ENABLED 0 to disable logging, as uart will cause the peripheral clock tree to run in sleep.

Kind regards,

Håkon

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Luca Nisti — Tue, 21 Apr 2026 11:06:02 GMT

The results are consistent with different boards.

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Luca Nisti — Tue, 21 Apr 2026 11:04:30 GMT

Good morning Håkon Alseth

1. We measured the board consumption removing the mcu from the pcb, plus it is consistent with calculation done by the hw engineer.

2. I checked the SDA and SCL pin status during the sleep mode and they are set correctly to save power

3. Attached the sdk config file. I can confirm we are using the NRF_TWIM and TWI0_USE_EASY_DMA and TWI1_USE_EASY_DMA

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Håkon Alseth — Tue, 21 Apr 2026 09:59:55 GMT

Hi,

If custom design; Is this repeatable on all your boards, or just one?

[quote user="Luca Nisti"]The board without mcu consume around 200uA.[/quote]

Does this mean that you physically remove or power off the nRF?

[quote user="Luca Nisti"]

Using the same firmware without initializing the I2C (twi0 an twi1 using easy dma) the consumption is around 250uA as expected and how we should want to have with the i2c disabled.

[/quote]

Could you verify that the SDA and SCL is set high, either by pull-up (via NRF_GPIO->PIN_CNF register), or externally?

If these pins are floating, you will see excessive current leaked.

Can you please share your sdk_config.h?

I want to explicitly see if you are using NRF_TWI or NRF_TWIM, by checking the defines "TWI0_USE_EASY_DMA" and "TWI1_USE_EASY_DMA".

If one or both are set to '0', try setting them to '1' and see if this has any impact.

Kind regards,

Håkon

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Luca Nisti — Mon, 20 Apr 2026 15:13:21 GMT

Håkon Alseth I am happy to run a debug session and report o you register status if you need to understand what is the issue.

Thank you for support

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Luca Nisti — Mon, 20 Apr 2026 13:45:42 GMT

The board does not have a pull-up-resistor to the SDA/SCL.

After disabling/uninit the i2c the consumption is still 550uA.
The board without mcu consume around 200uA.

The mcu is in SystemOn and adversting, using the Online Power Profiler for Bluetooth LE the mcu shall consume around 50uA.

Using the same firmware without initializing the I2C (twi0 an twi1 using easy dma) the consumption is around 250uA as expected and how we should want to have with the i2c disabled.

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Håkon Alseth — Mon, 20 Apr 2026 13:36:45 GMT

Hi,

Do you still measure 550 uA?

Have you applied pull-resistors to the SDA/SCL lines after disabling the NRF_TWI instances?

Kind regards,

Håkon

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Luca Nisti — Mon, 20 Apr 2026 13:31:12 GMT

Good afternoon, I tried the following code with no success

    NRF_TWI_MNGR_DEF(nrfTwiMngr0, MAX_PENDING_TRANSACTIONS, TWI_INSTANCE_ID0);
    NRF_TWI_MNGR_DEF(nrfTwiMngr1, MAX_PENDING_TRANSACTIONS, TWI_INSTANCE_ID1);
    static const nrf_twi_mngr_t* const busToTwiInstance[I2C_BUS_N] =
    {
        &nrfTwiMngr0,
        &nrfTwiMngr1
    };
    
    

    nrf_drv_twi_disable(&busToTwiInstance[0]->twi);
    nrf_twi_mngr_uninit(busToTwiInstance[0]);
    nrf_drv_twi_disable(&busToTwiInstance[1]->twi);
    nrf_twi_mngr_uninit(busToTwiInstance[1]);

    *(volatile uint32_t *)0x40003FFC = 0;
    *(volatile uint32_t *)0x40003FFC;
    *(volatile uint32_t *)0x40003FFC = 1;
    *(volatile uint32_t *)0x40004FFC = 0;
    *(volatile uint32_t *)0x40004FFC;
    *(volatile uint32_t *)0x40004FFC = 1;

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Håkon Alseth — Mon, 20 Apr 2026 08:42:56 GMT

Hi,

I suspect that this erratum is the root cause of the higher current consumption while in sleep:

https://docs.nordicsemi.com/bundle/errata_nRF52832_Rev3/page/ERR/nRF52832/Rev3/latest/anomaly_832_89.html#anomaly_832_89

Could you try to implement this and see if you are able to reach the expected current consumption?

Kind regards,

Håkon

RE: nrf52832 power consumption when disabling Twi driver (i2c)

Luca Nisti — Fri, 17 Apr 2026 16:40:21 GMT

errata, we use SDK version 17.1.0