How to keep nRF5340 in low power mode with BLE always ON and UART active only during data transfer (with no data loss)?

RE: How to keep nRF5340 in low power mode with BLE always ON and UART active only during data transfer (with no data loss)?

Turbo J — Wed, 23 Jul 2025 10:44:14 GMT

Nopers.

It will have to be System ON with the HF clock running at very roughly 0.5mA current consumtion. Check the datasheet/PS for details.

Low power mode typically means less consumtion, but YMMV.

RE: How to keep nRF5340 in low power mode with BLE always ON and UART active only during data transfer (with no data loss)?

pal_722 — Wed, 23 Jul 2025 10:13:23 GMT

Hi
Did you mean the nrf has to be SYSTEM-ON Low Power mode?

RE: How to keep nRF5340 in low power mode with BLE always ON and UART active only during data transfer (with no data loss)?

Turbo J — Wed, 23 Jul 2025 07:47:58 GMT

Not possible, especially at high baud rates. Whenever the UART is ready to receive ("RX started"), it will keep the HFINT running. At high baud rates I would also recommend requesting HFCLK running.

You have to keep the UART(E) peripherial in active state in order to be able to receive data at all. It can't wake up on data receive alone.