Add examples

Signed-off-by: fpr <[email protected]>

Author: fpr

examples/ExternalWakeup/ExternalWakeup.ino

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+/*
+  ExternalWakeup
+
+  This sketch demonstrates the usage of External Interrupts (on pins) to wakeup
+  a chip in sleep mode. Sleep modes allow a significant drop in the power usage
+  of a board while it does nothing waiting for an event to happen.
+  Battery powered application can take advantage of these modes to enhance
+  battery life significantly.
+
+  In this sketch, pressing a pushbutton attached to pin will wake up the board.
+
+  This example code is in the public domain.
+*/
+
+#include "STM32LowPower.h"
+
+// Blink sequence number
+// Declare it volatile since it's incremented inside an interrupt
+volatile int repetitions = 1;
+
+// Pin used to trigger a wakeup
+const int pin = USER_BTN;
+
+void setup() {
+  pinMode(LED_BUILTIN, OUTPUT);
+  // Set pin as INPUT_PULLUP to avoid spurious wakeup
+  pinMode(pin, INPUT_PULLUP);
+
+  // Configure low power
+  LowPower.begin();
+  // Attach a wakeup interrupt on pin, calling repetitionsIncrease when the device is woken up
+  LowPower.attachInterruptWakeup(pin, repetitionsIncrease, RISING);
+}
+
+void loop() {
+  for (int i = 0; i < repetitions; i++) {
+    digitalWrite(LED_BUILTIN, HIGH);
+    delay(500);
+    digitalWrite(LED_BUILTIN, LOW);
+    delay(500);
+  }
+  // Triggers an infinite sleep (the device will be woken up only by the registered wakeup sources)
+  // The power consumption of the chip will drop consistently
+  LowPower.sleep();
+}
+
+void repetitionsIncrease() {
+  // This function will be called once on device wakeup
+  // You can do some little operations here (like changing variables which will be used in the loop)
+  // Remember to avoid calling delay() and long running functions since this functions executes in interrupt context
+  repetitions ++;
+}

examples/SerialDeepSleep/SerialDeepSleep.ino

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+/*
+  SerialDeepSleep
+
+  This sketch demonstrates the usage of Serial Interrupts to wakeup a chip
+  in deep sleep mode.
+
+  This sketch is compatible only with board supporting uart peripheral in
+  stop mode.
+
+  This example code is in the public domain.
+*/
+
+#include "STM32LowPower.h"
+
+// Declare it volatile since it's incremented inside an interrupt
+volatile int wakeup_counter = 0;
+
+void setup() {
+  Serial.begin(9600);
+  // initialize digital pin LED_BUILTIN as an output.
+  pinMode(LED_BUILTIN, OUTPUT);
+  // Configure low power
+  LowPower.begin();
+  // Enable UART in Low Power mode wakeup source
+  LowPower.enableWakeupFrom(&Serial, SerialWakeup);
+  Serial.println("Start deep sleep wakeup from Serial");
+}
+
+void loop() {
+  digitalWrite(LED_BUILTIN, HIGH);
+  delay(500);
+  digitalWrite(LED_BUILTIN, LOW);
+  delay(500);
+  // Triggers an infinite deep sleep
+  // (the device will be woken up only by the registered wakeup sources)
+  // The power consumption of the chip will drop consistently
+  LowPower.deepSleep();
+
+  Serial.print(wakeup_counter);
+  Serial.println(" wake up");
+
+  // Empty Serial Rx
+  while(Serial.available()) {
+    char c = Serial.read();
+    Serial.print(c);
+  }
+  Serial.println();
+}
+
+void SerialWakeup() {
+  // This function will be called once on device wakeup
+  // You can do some little operations here (like changing variables
+  // which will be used in the loop)
+  // Remember to avoid calling delay() and long running functions
+  // since this functions executes in interrupt context
+  wakeup_counter++;
+}

examples/TimedWakeup/TimedWakeup.ino

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+/*
+  TimedWakeup
+
+  This sketch demonstrates the usage of Internal Interrupts to wakeup a chip
+  in deep sleep mode.
+
+  In this sketch, the internal RTC will wake up the processor every second.
+
+  This example code is in the public domain.
+*/
+
+#include "STM32LowPower.h"
+
+void setup() {
+  pinMode(LED_BUILTIN, OUTPUT);
+  // Configure low power
+  LowPower.begin();
+}
+
+void loop() {
+  digitalWrite(LED_BUILTIN, HIGH);
+  LowPower.deepSleep(1000);
+  digitalWrite(LED_BUILTIN, LOW);
+  LowPower.deepSleep(1000);
+}