95 lines
3.1 KiB
C++
95 lines
3.1 KiB
C++
/*
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Simple Deep Sleep with Timer Wake Up
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=====================================
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ESP32 offers a deep sleep mode for effective power
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saving as power is an important factor for IoT
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applications. In this mode CPUs, most of the RAM,
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and all the digital peripherals which are clocked
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from APB_CLK are powered off. The only parts of
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the chip which can still be powered on are:
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RTC controller, RTC peripherals ,and RTC memories
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This code displays the most basic deep sleep with
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a timer to wake it up and how to store data in
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RTC memory to use it over reboots
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This code is under Public Domain License.
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Author:
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Pranav Cherukupalli <cherukupallip@gmail.com>
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*/
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#define uS_TO_S_FACTOR 1000000 /* Conversion factor for micro seconds to seconds */
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#define TIME_TO_SLEEP 5 /* Time ESP32 will go to sleep (in seconds) */
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RTC_DATA_ATTR int bootCount = 0;
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/*
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Method to print the reason by which ESP32
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has been awaken from sleep
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*/
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void print_wakeup_reason(){
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esp_sleep_wakeup_cause_t wakeup_reason;
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wakeup_reason = esp_sleep_get_wakeup_cause();
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switch(wakeup_reason)
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{
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case 1 : Serial.println("Wakeup caused by external signal using RTC_IO"); break;
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case 2 : Serial.println("Wakeup caused by external signal using RTC_CNTL"); break;
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case 3 : Serial.println("Wakeup caused by timer"); break;
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case 4 : Serial.println("Wakeup caused by touchpad"); break;
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case 5 : Serial.println("Wakeup caused by ULP program"); break;
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default : Serial.printf("Wakeup was not caused by deep sleep: %d\n",wakeup_reason); break;
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}
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}
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void setup(){
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Serial.begin(115200);
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delay(1000); //Take some time to open up the Serial Monitor
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//Increment boot number and print it every reboot
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++bootCount;
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Serial.println("Boot number: " + String(bootCount));
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//Print the wakeup reason for ESP32
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print_wakeup_reason();
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/*
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First we configure the wake up source
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We set our ESP32 to wake up every 5 seconds
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*/
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esp_sleep_enable_timer_wakeup(TIME_TO_SLEEP * uS_TO_S_FACTOR);
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Serial.println("Setup ESP32 to sleep for every " + String(TIME_TO_SLEEP) +
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" Seconds");
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/*
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Next we decide what all peripherals to shut down/keep on
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By default, ESP32 will automatically power down the peripherals
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not needed by the wakeup source, but if you want to be a poweruser
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this is for you. Read in detail at the API docs
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http://esp-idf.readthedocs.io/en/latest/api-reference/system/deep_sleep.html
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Left the line commented as an example of how to configure peripherals.
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The line below turns off all RTC peripherals in deep sleep.
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*/
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//esp_deep_sleep_pd_config(ESP_PD_DOMAIN_RTC_PERIPH, ESP_PD_OPTION_OFF);
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//Serial.println("Configured all RTC Peripherals to be powered down in sleep");
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/*
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Now that we have setup a wake cause and if needed setup the
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peripherals state in deep sleep, we can now start going to
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deep sleep.
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In the case that no wake up sources were provided but deep
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sleep was started, it will sleep forever unless hardware
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reset occurs.
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*/
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Serial.println("Going to sleep now");
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Serial.flush();
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esp_deep_sleep_start();
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Serial.println("This will never be printed");
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}
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void loop(){
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//This is not going to be called
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}
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