samples: board: stm32 pm: add adc power management sample

# SPDX-License-Identifier: Apache-2.0

cmake_minimum_required(VERSION 3.20.0)

find_package(Zephyr REQUIRED HINTS $ENV{ZEPHYR_BASE})

project(stm32_pm_adc)

target_sources(app PRIVATE src/main.c)

.. _stm32-pm-adc-sample:

STM32 PM ADC

############

Overview

********

This sample is a minimum application to demonstrate basic power management

behavior in a basic ADC set up in low power context.

.. _stm32-pm-adc-sample-requirements:

Requirements

************

The board should support enabling PM. For a STM32 based target, it means that

it should support a clock source alternative to Cortex Systick that can be used

in core sleep states, as LPTIM (:dtcompatible:`st,stm32-lptim`).

Building and Running

********************

Build and flash as follows, changing ``nucleo_wb55rg`` for your board:

.. zephyr-app-commands::

   :zephyr-app: samples/boards/stm32/power_mgmt/adc

   :board: nucleo_wb55rg

   :goals: build flash

   :compact:

After flashing, the console shows the ADC measurement in the form:

``ADC reading[0]:``

``- adc@50040000, channel 3: 1158 = 932 mV``

PM configurations

*****************

By default, :kconfig:option:`CONFIG_PM_DEVICE` and :kconfig:option:`CONFIG_PM_DEVICE_RUNTIME` are

enabled.

On STM32WB, we can observe a power consumption of about 25µA with both kconfig

enabled, 27.5µA without (each time with :kconfig:option:`CONFIG_PM` enabled).

/*

 * SPDX-License-Identifier: Apache-2.0

 *

 * Copyright (c) 2023 STMicroelectronics

 */

#include <zephyr/dt-bindings/adc/adc.h>

/ {

	zephyr,user {

		/* adjust channel number according to pinmux in board.dts */

		io-channels = <&adc1 1>;

	};

};

&adc1 {

	#address-cells = <1>;

	#size-cells = <0>;

	channel@1 {

		reg = <1>;

		zephyr,gain = "ADC_GAIN_1";

		zephyr,reference = "ADC_REF_INTERNAL";

		zephyr,acquisition-time = <ADC_ACQ_TIME_DEFAULT>;

		zephyr,resolution = <12>;

	};

};

/*

 * SPDX-License-Identifier: Apache-2.0

 *

 * Copyright (c) 2023 STMicroelectronics

 */

/ {

	zephyr,user {

		/* adjust channel number according to pinmux in board.dts */

		io-channels = <&adc1 3>;

	};

};

&adc1 {

	pinctrl-0 = <&adc1_in3_pc2>;

	#address-cells = <1>;

	#size-cells = <0>;

	channel@3 {

		reg = <3>;

		zephyr,gain = "ADC_GAIN_1";

		zephyr,reference = "ADC_REF_INTERNAL";

		zephyr,acquisition-time = <ADC_ACQ_TIME_MAX>;

		zephyr,resolution = <12>;

	};

};

/*

 * SPDX-License-Identifier: Apache-2.0

 *

 * Copyright (c) 2023 STMicroelectronics

 */

/ {

	zephyr,user {

		/* adjust channel number according to pinmux in board.dts */

		io-channels = <&adc4 8>;

	};

};