+ // Enable watchdog to wake from MCU sleep
+ cli();
+ wdt_reset();
+
+ // Watchdog Interrupt and System Reset Mode
+ //wdt_enable(WDTO_1S);
+ //WDTCSR |= _BV(WDIE);
+
+ // Watchdog Interrupt Mode
+ wdt_intr_enable(WDTO_120MS);
+
+ // TODO: more power saving
+ // See PicoPower application note
+ // - I/O port input with pullup
+ // - prescale clock
+ // - BOD disable
+ // - Power Reduction Register PRR
+ // sleep in power down mode
+ set_sleep_mode(SLEEP_MODE_PWR_DOWN);
+ sleep_enable();
+ sei();
+ sleep_cpu();
+ sleep_disable();
+
+ // Disable watchdog after sleep
+ wdt_disable();
+
+ // Send request of USB Wakeup from Suspend to host