diff --git a/delay.c b/delay.c
index 0468c02..bf0be85 100644
--- a/delay.c
+++ b/delay.c
@@ -4,20 +4,33 @@
 	\brief Delay routines
 */
 
-#include <util/delay_basic.h>
+//#include <util/delay_basic.h>
 
-#include	"watchdog.h"
+//#include	"watchdog.h"
+
+
+/// interruptable microsecond delay
+/// does NOT call wd_reset
+/// \param delay time in microseconds
+void delay_us( uint16_t delay )
+{
+	while (delay > (65536UL / (F_CPU / 4000000UL))) {
+		_delay_loop_2(65534); //
+		delay -= (65536L / (F_CPU / 4000000L));
+	}
+	_delay_loop_2( delay * (F_CPU / 4000000UL));
+}
 
 /// delay microseconds
 /// \param delay time to wait in microseconds
-void delay_us(uint16_t delay) {
+void _delay(uint32_t delay) {
 	wd_reset();
 	while (delay > (65536L / (F_CPU / 4000000L))) {
 		_delay_loop_2(65534); // we use 65534 here to compensate for the time that the surrounding loop takes. TODO: exact figure needs tuning
 		delay -= (65536L / (F_CPU / 4000000L));
 		wd_reset();
 	}
-	_delay_loop_2(delay / (F_CPU / 4000000L));
+	_delay_loop_2(delay * (F_CPU / 4000000L));
 	wd_reset();
 }
 
diff --git a/delay.h b/delay.h
index 4631928..e507199 100644
--- a/delay.h
+++ b/delay.h
@@ -3,28 +3,49 @@
 
 #include	<stdint.h>
 #include	<util/delay_basic.h>
+#include	"watchdog.h"
 
 #define		WAITING_DELAY		100
 
+#if F_CPU < 4000000UL
+#error Delay functions only work with F_CPU >= 4000000UL 
+#endif
+
+// microsecond delay, does NOT reset WDT if feature enabled
 void delay_us(uint16_t delay);
 
+// microsecond delay, does reset WDT if feature enabled
+void _delay(uint32_t delay);
+
+// millisecond delay, does reset WDT if feature enabled
 void _delay_ms(uint32_t delay);
 
+
+// microsecond timer, does reset WDT if feature enabled
+// 0 results in no real delay, but the watchdog
+// reset is called if the feature is enabled
 static void delay(uint32_t) __attribute__ ((always_inline));
 inline void delay(uint32_t d) {
-	if (d >= (65536L / (F_CPU / 4000000L))) {
-		delay_us(d);
+	if (d > (65536L / (F_CPU / 4000000L))) {
+		_delay(d);
+	}
+	else {
+		wd_reset();
+		if( d ) {
+			_delay_loop_2(d * (F_CPU / 4000000L));
+			wd_reset();
+		}
 	}
-	else
-		_delay_loop_2(d * (F_CPU / 4000000L));
 }
 
+// millisecond timer, does reset WDT if feature enabled
+// 0 results in no real delay, but the watchdog
+// reset is called if the feature is enabled
 static void delay_ms(uint32_t) __attribute__ ((always_inline));
 inline void delay_ms(uint32_t d) {
 	if (d > 65)
-		delay_ms(d);
+		_delay_ms(d);
 	else
-		delay_us(d * 1000);
-}
-
+		delay(d * 1000);
+ }
 #endif	/* _DELAY_H */