Low Power UART

The Low Power UART sample demonstrates the capabilities of the Low power UART driver module.

Overview

The sample implements a simple loopback using a single UART instance. The sample has console and logging disabled by default, to demonstrate low power consumption while having UART active.

Requirements

The sample supports the following development kits:

Hardware platforms

PCA

Board name

Build target

nRF9160 DK

PCA10090

nrf9160dk_nrf9160

nrf9160dk_nrf9160

nRF52840 DK

PCA10056

nrf52840dk_nrf52840

nrf52840dk_nrf52840

nRF52833 DK

PCA10100

nrf52833dk_nrf52833

nrf52833dk_nrf52833

nRF52 DK

PCA10040

nrf52dk_nrf52832

nrf52dk_nrf52832

nRF5340 DK

PCA10095

nrf5340dk_nrf5340

nrf5340dk_nrf5340_cpuapp

The sample also requires the following pins to be shorted:

  • TX (Arduino Digital Pin 10) with RX (Arduino Digital Pin 11)

  • Request Pin (Arduino Digital Pin 12) with Response Pin (Arduino Digital Pin 13)

Additionally, it requires a logic analyzer.

Building and running

This sample can be found under samples/peripheral/lpuart in the nRF Connect SDK folder structure.

See Building and programming a sample application for information about how to build and program the application.

Testing

After programming the sample to your development kit, test it by performing the following steps:

  1. Connect the logic analyzer to the shorted pins, to confirm UART activity.

  2. Measure the current to confirm that the power consumption indicates that high-frequency clock is disabled during the idle stage. During the idle stage, the UART receiver is ready to start reception, as the request pin wakes it up.

Dependencies

This sample uses the following nRF Connect SDK driver:

In addition, it uses the following Zephyr libraries: