   static int32_t cycle = 1;
 
   // Wait for rising edge on clock pin
+#if defined(SQUARE_WAVE_CLOCK)
   while (clkPin.is_clear()) yield();
+#else
+  clock.await();
+#endif
   ledPin.set();
 
   // Read the time from the rtc device and print

OutputPin ledPin(Board::LED);

// Clock pin
#if defined(ARDUINO_PRO_MICRO)
InputPin clkPin(Board::D0);
#else
InputPin clkPin(Board::D2);
#endif

void setup()

#include "Cosa/Trace.hh"
#include "Cosa/IOStream/Driver/UART.hh"

// Set the extern RTC
// #define SET_TIME

// Synchronized with external RTC square-ware
// #define SQUARE_WAVE_CLOCK

// The real-time device, latest start and sample time in ram
DS1307 rtc;
