Move master branch from from mios git repo

libraries/InterruptChain/examples/Basic/Basic.ino

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+/**
+ * Demo of a chained interrupt handler.
+ *
+ * This sketch duplicates the signal on digital pin 2 to digital pin 13 (the LED) and
+ * echos the value on the serial line. (so open up the serial console @ 9600 baud)
+ *
+ * Hardware setup for this example:
+ *  - Attach a switch from ground to pin 2, or use a wire from ground to pin 2.
+ */
+
+#include <InterruptChain.h>
+
+void echoLed() {
+  digitalWrite(13, digitalRead(2));
+}
+
+void echoSerial() {
+  // Within interrupts handlers, interrupts are disabled.
+  // However, Serial doesn't seem to like it when interrupts are disabled,
+  // causing hangs when the transmit buffer is full.
+  // First, disable the interrupt chain, to prevent race conditions.
+  // Then enable interrupts.
+  InterruptChain::disable(0);
+  interrupts();
+
+  if (digitalRead(2)) {
+    Serial.println("The signal is HIGH!");
+  } else {
+    Serial.println("The signal is LOW!");
+  }
+
+  // Disabling interrupts before enabling the interrupt chain.
+  noInterrupts();
+  InterruptChain::enable(0);
+}
+
+void setup() {
+    Serial.begin(9600);
+    pinMode(13, OUTPUT);
+
+    // Enable internal pull-up on pin 2.
+	// This is merely for this demo; it is not required for interrupt handling.
+    digitalWrite(2, HIGH);
+
+    // Links two callback to interrupt 0 with default mode CHANGE.
+    InterruptChain::addInterruptCallback(0, echoLed);
+    InterruptChain::addInterruptCallback(0, echoSerial);
+}
+
+void loop() {
+   // You can do other stuff here!
+}