How to disable and enable UART at runtime to avoid TX current when connected UART device is POWERD OFF ?

RE: How to disable and enable UART at runtime to avoid TX current when connected UART device is POWERD OFF ?

Karl Ylvisaker — Fri, 21 Jul 2023 11:14:25 GMT

Hello again,

I am glad to hear that you were able to achieve the lower power consumption!
Using the power management module to disable the peripheral is also a good way to approach this.

For the record, you can use these predefined PM actions with the call to pm_device_action_run, instead of the '0' argument, for convenience, readability, and maintainability :)

Best regards,
Karl

RE: How to disable and enable UART at runtime to avoid TX current when connected UART device is POWERD OFF ?

vinodsdw — Thu, 20 Jul 2023 07:31:45 GMT

I tried to find such uninit functions but couldn't find those.

Instead I called the below function and those disabled the PORT and made the PINs are input floating.

pm_device_action_run(uart_dev1, 0);

pm_device_action_run(uart_dev2, 0);

pm_device_action_run(i2c, 0);

pm_device_action_run(spi, 0);

This reduced power consumption drastically and now able to achieve < 50uA with Bluetooth advertising.

RE: How to disable and enable UART at runtime to avoid TX current when connected UART device is POWERD OFF ?

Karl Ylvisaker — Wed, 19 Jul 2023 12:04:57 GMT

Hello,

[quote user="vinodsdw"]Now irrespective of the rtos sleep/idle, if I want to disable the sensor, I am turning OFF the sensor VDD by above mentioned method. Now if I turn off the sensor, then I need to immediately turn OFF the UART to INPUT mode to save current drawn via the TX pin.[/quote]

Thank you for clarifying, you can achieve this using the uninit function which you can call at the same time you are cutting the power to the sensor.

[quote user="vinodsdw"]I will check the e driver's uninit function to see if I can disable and enable the driver in runtime.[/quote]

Alright, let me know if you should encounter any other issues or questions when doing this! :)

Best regards,
Karl

RE: How to disable and enable UART at runtime to avoid TX current when connected UART device is POWERD OFF ?

vinodsdw — Tue, 18 Jul 2023 13:53:57 GMT

I mean I am using a GPIO to control the power (vdd) of external sensor by using P-Mosfet.

Now irrespective of the rtos sleep/idle, if I want to disable the sensor, I am turning OFF the sensor VDD by above mentioned method. Now if I turn off the sensor, then I need to immediately turn OFF the UART to INPUT mode to save current drawn via the TX pin.

I will check the e driver's uninit function to see if I can disable and enable the driver in runtime.

RE: How to disable and enable UART at runtime to avoid TX current when connected UART device is POWERD OFF ?

Karl Ylvisaker — Tue, 18 Jul 2023 13:04:14 GMT

Hello,

[quote user=""]How to disable and enable UART on runtime to avoid TX current when connected UART device is POWERD OFF ? (NRF5340)[/quote]

Do you here mean SYSTEM_ON sleep when you say POWERED OFF?
In the case of SYSTEM_OFF sleep no peripherals will be enabled, and so the UART would not be contributing to any power leakage in this case.

You can still use the driver's uninit function to uninit the driver at any time during runtime, and then use the corresponding init function again when you require the UART functionality, if this is what you are asking.

Please let me know and elaborate more on the desired behavior if this was not what you were asking about.

Best regards,
Karl