75 lines
2.5 KiB
ReStructuredText
75 lines
2.5 KiB
ReStructuredText
.. _esp32-deep-sleep-sample:
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ESP32 Deep Sleep demo
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#####################
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Overview
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********
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The deep sleep mode of the ESP32 Series is a power saving mode that causes the
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CPU, majority of RAM, and digital peripherals that are clocked from APB_CLK to
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be powered off.
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This sample shows how to set a wake up source, trigger deep sleep and then
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make use of that pre-configured wake up source to bring the system back again.
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The following wake up sources are demonstrated in this example:
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1. ``Timer``: An RTC timer that can be programmed to trigger a wake up after
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a preset time. This example will trigger a wake up every 20 seconds.
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2. ``EXT1``: External wake up 1 is tied to multiple RTC GPIOs. This example
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uses GPIO2 and GPIO4 to trigger a wake up with any one of the two pins are
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HIGH.
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3. ``GPIO``: Only supported by some Espressif SoCs, in the case of ESP32-C3
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GPIOS0~5 can be used as wake-up sources.
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In this demo, Timer is the only wake-up source that cannot be disabled via a
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Kconfig option. The target SoC will always repeat the following: enable Timer
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as wake-up source, deep sleep for 20 seconds, wake up.
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Requirements
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************
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This example should be able to run on any commonly available
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:ref:`esp32_devkitc_wroom` development board without any extra hardware if
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only ``Timer`` is used as wakeup source.
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However, when ``EXT1`` is also enabled, GPIO2 and GPIO4 should be pulled-down
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by external resistors to avoid floating pins. When triggering a wake up, one
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or both of the pins must be set to high. Note that floating pins may trigger
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a wake up.
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The same connection logic used on ``EXT1`` should be applied when ``GPIO`` is
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enabled as wake-up source.
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To enable or disable ``EXT1``, edit ``CONFIG_EXAMPLE_EXT1_WAKEUP`` on demo's
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``prj.conf`` file. By default, this wake up source is enabled. Follow similar
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steps to enable or disable ``GPIO`` by editing ``CONFIG_EXAMPLE_GPIO_WAKEUP``.
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Building, Flashing and Running
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******************************
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.. zephyr-app-commands::
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:zephyr-app: samples/boards/esp32/deep_sleep
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:board: esp32_devkitc_wroom/esp32/procpu
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:goals: build flash
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:compact:
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Sample Output
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=================
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ESP32 core output
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-----------------
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With both wake up sources enabled, the console output will be as below. The
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reset reason message depends on the wake up source used. The console output
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sample below is for GPIO2.
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.. code-block:: console
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*** Booting Zephyr OS build zephyr-v3.1.0-3667-gb42e2b225ecf ***
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Wake up from GPIO 2
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Enabling timer wakeup, 20s
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Enabling EXT1 wakeup on pins GPIO2, GPIO4
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Powering off
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