add devterm_keyboard_mini init code

Code/devterm_keyboard_mini/debouncer.h

@@ -0,0 +1,53 @@
+#ifndef DEBOUNCER_H
+#define DEBOUNCER_H
+
+#include <cstdint>
+
+typedef uint8_t millis_t;
+
+const millis_t DEBOUNCE_MS = 5;
+
+/**
+   @brief Asymmetric debouncer
+*/
+class Debouncer {
+  public:
+    Debouncer();
+    void updateTime(millis_t delta);
+    bool sample(bool value);
+  private:
+    millis_t timeout;
+};
+
+template<typename T, T millis>
+class Timeout {
+  public:
+    Timeout() {
+      timeout = 0;
+    }
+
+    void updateTime(millis_t delta) {
+      if (timeout > delta) {
+        timeout -= delta;
+      } else {
+        timeout = 0;
+      }
+    }
+
+    void expire() {
+      timeout = 0;
+    }
+
+    bool get() const {
+      return timeout == 0;
+    }
+
+    void reset() {
+      timeout = millis;
+    }
+  private:
+    uint16_t timeout;
+};
+
+
+#endif