High power consumption after uninit of libuarte

RE: High power consumption after uninit of libuarte

ilockit_CFR — Wed, 22 May 2024 11:53:37 GMT

Hi Vidar,

thanks for your support. I tried the code snippet, but nothing changes. So I initialised the UART with two different pins and that led to the correct result. The power consumption was reduced to the expected value after uninit. Obviously, there's an issue with our pcb but that's something I have to discuss with our team.

Thanks for your time and your help.

Best regards,

Christian

RE: High power consumption after uninit of libuarte

Vidar Berg — Wed, 22 May 2024 11:38:10 GMT

Hi Christian,

Thanks for sharing the project. Unfortunately, I'm currently unable to build Keil projects as I'm running Ubuntu, but I did look at the code and did not spot any errors.

Please try to add the code snippet below after libuarte uninit and see if it makes any difference. This will help confirm if the UARTE peripheral is the culprit or not.

    /* Power-cycle UARTE0 to force release of HF clock request */
    *(volatile uint32_t *)(NRF_UARTE0_BASE + 0xFFC) = 0;
    *(volatile uint32_t *)(NRF_UARTE0_BASE + 0xFFC);
    *(volatile uint32_t *)(NRF_UARTE0_BASE + 0xFFC) = 1;

Best regards,

Vidar

RE: High power consumption after uninit of libuarte

ilockit_CFR — Wed, 22 May 2024 10:12:57 GMT

Hi Vidar,

thanks for the hint. I prepared a minimal example. Unfortunately, I have no dev-kit here at the moment, so that I could only test with our custom pcb. I hope it works on your side.

Best regards,

Christian

RE: High power consumption after uninit of libuarte

Vidar Berg — Wed, 22 May 2024 08:20:00 GMT

Hi Christian,

You can use the nrf_drv_clock_hfclk_request() function to start up the crystal oscillator, and nrf_drv_clock_hfclk_release() when you no longer need it.

Are you able to share a minimal version of your project so I can try to replicate this issue on a DK?

Best regards,

Vidar

RE: High power consumption after uninit of libuarte

ilockit_CFR — Wed, 22 May 2024 07:10:19 GMT

Hi Vidar,

we only have one other pin to activate/deactivate the modem part, but for the tests this pin is set to LOW the whole time.

The application does not request the HF oscillator when initialising the UART. How would I do that? I checked it with nrf_drv_clock_hfclk_is_running and it always returned false.

Best regards,

Christian

RE: High power consumption after uninit of libuarte

Vidar Berg — Wed, 22 May 2024 06:28:22 GMT

Hi Christian,

Thanks for confirming. Is your application requesting the HF crystal oscillator when it enables the UARTE as recommended in the PS? Are there any other pins being used for interfacing with the GSM modem apart from the RX and TX pins? A current draw of 2-300 µA often indicates that there is a floating input or that the crystal oscillator is left running.

Best regards,

Vidar

RE: High power consumption after uninit of libuarte

ilockit_CFR — Wed, 22 May 2024 06:18:43 GMT

Hi Vidar,

at the moment the GSM modem is completely disconnected. We observed higher current consumption after using the modem so we investigated where it comes from. We could break it down to the initialisation and uninitialisartion of the UART after we disconnected the whole modem part. So I guessed that there's an issue with the configuration or usage of the UART library, bubt I couldn't find any solution in your examples or the devzone.

Best regards,

Christian

RE: High power consumption after uninit of libuarte

Vidar Berg — Tue, 21 May 2024 13:35:16 GMT

Hi Christian,

Based on the pin naming, I assume that you are connected to a GSM modem. Is the current going into the modem part of the measurement, or do you power it off after disabling the UART?

Best regards,

Vidar