How to power down the UART on nrf52832

[riceman0]

Hello, we are trying to use a uart while minimizing power consumption.  On this post

https://devzone.nordicsemi.com/f/nordic-q-a/26030/how-to-reach-nrf52840-uarte-current-supply-specification/102605#102605

It's said that the way to shut off uart and all clocks, etc, to minimize power consumption you need to run the register assigments below after closing the uart.

But this is for the nrf52840. What is the equivalent code on the nrf52832?

Also, is this still necessary? Or has it been resolved?

Thanks.

uart_close();
*(volatile uint32_t *)0x40002FFC = 0;
*(volatile uint32_t *)0x40002FFC;
*(volatile uint32_t *)0x40002FFC = 1;

[Jørgen Holmefjord]

Hi,

Are you seeing abnormal current consumption after disabling UART with the uart_close() function? The workaround in the thread you are linking is related to this errata. If you are not seeing excessive current consumption, there is no need to implement the workaround. The base address for UARTE0 is the same on nRF52832 as nRF52840, the workaround is identical for the two devices.

Best regards,
Jørgen

[riceman0]

Actually I am seeing the ble_app_uart example, after app_uart_close, we don't see the power drop nearly as much as the blinky example while advertising.

Are those the wrong registers for this peripheral?  (I actually don't understand the difference between UARTE0 and UART...)

https://devzone.nordicsemi.com/f/nordic-q-a/59373/how-to-power-down-the-uart-on-nrf52832

[Jørgen Holmefjord]

The current consumption of the examples will depend on many factors, especially how often packets are transmitted over BLE. I checked the ble_app_uart example with and without the errata 89 workaround, and I do not see any difference in average current consumption (~480 uA):

 

This is also in line with the expected current consumption reported by the nRF Online Power Profiler (I may have entered too large packet payload, which could explain the higher current reported by the calculator):

If you want a lower current consumption, you should try to increase the advertising interval in the application.

[riceman0]

Thanks... I'll compare and contrast to what I'm seeing when I can get back to my equipment. :)