diff --git a/conf/Makefile.sim b/conf/Makefile.sim
index 8830edd81d..34db63a13d 100644
--- a/conf/Makefile.sim
+++ b/conf/Makefile.sim
@@ -51,12 +51,12 @@ ifneq ($(SIM_TYPE),JSBSIM)
 INCLUDES += -I `ocamlc -where`
 endif
 
-CFLAGS		=						\
-	-W -Wall 						\
-	$(INCLUDES)					  	\
-	$($(TARGET).CFLAGS)					\
-	$(LOCAL_CFLAGS)						\
-	-O2							\
+CFLAGS  = -W -Wall
+CFLAGS += $(INCLUDES)
+CFLAGS += $($(TARGET).CFLAGS)
+CFLAGS += $(LOCAL_CFLAGS)
+CFLAGS += -O2
+CFLAGS += -std=gnu99
 
 # meschach prototypes trigger numerous warnings
 ifneq ($(SIM_TYPE),BOOZ)
@@ -66,7 +66,7 @@ endif
 endif
 
 
-LDFLAGS		=	-lm					\
+LDFLAGS		=	-lm
 
 ifeq ($(SIM_TYPE),BOOZ)
 LDFLAGS		+= $($(TARGET).LDFLAGS)
diff --git a/conf/autopilot/subsystems/fixedwing/autopilot.makefile b/conf/autopilot/subsystems/fixedwing/autopilot.makefile
index d63af15830..090911bbaa 100644
--- a/conf/autopilot/subsystems/fixedwing/autopilot.makefile
+++ b/conf/autopilot/subsystems/fixedwing/autopilot.makefile
@@ -71,7 +71,7 @@ ifndef PERIODIC_FREQUENCY
 PERIODIC_FREQUENCY = 60
 endif
 $(TARGET).CFLAGS += -DPERIODIC_TASK_PERIOD='CPU_TICKS_OF_SEC((1./$(PERIODIC_FREQUENCY).))' -DPERIODIC_FREQUENCY=$(PERIODIC_FREQUENCY)
-$(TARGET).srcs += mcu_periph/sys_time.c
+$(TARGET).srcs += mcu_periph/sys_time.c $(SRC_ARCH)/mcu_periph/sys_time_arch.c
 
 #
 # InterMCU & Commands
@@ -127,7 +127,6 @@ endif
 # Sys-time
 #
 ns_CFLAGS 		+= -DUSE_SYS_TIME -DSYS_TIME_RESOLUTION='(1./300.)'
-ns_srcs 		+= $(SRC_ARCH)/mcu_periph/sys_time_arch.c
 
 
 #
diff --git a/conf/autopilot/subsystems/rotorcraft/fdm_nps.makefile b/conf/autopilot/subsystems/rotorcraft/fdm_nps.makefile
index ea4bd2fae4..8e0ae66853 100644
--- a/conf/autopilot/subsystems/rotorcraft/fdm_nps.makefile
+++ b/conf/autopilot/subsystems/rotorcraft/fdm_nps.makefile
@@ -70,7 +70,7 @@ endif
 
 sim.CFLAGS += -DPERIODIC_TASK_PERIOD='CPU_TICKS_OF_SEC((1./512.))'
 #sim.CFLAGS += -DUSE_LED
-sim.srcs += mcu_periph/sys_time.c
+sim.srcs += mcu_periph/sys_time.c $(SRC_ARCH)/mcu_periph/sys_time_arch.c
 
 sim.srcs += subsystems/settings.c
 sim.srcs += $(SRC_ARCH)/subsystems/settings_arch.c
diff --git a/sw/airborne/arch/lpc21/mcu_periph/sys_time_arch.c b/sw/airborne/arch/lpc21/mcu_periph/sys_time_arch.c
index 25c771c96b..076cd64f05 100644
--- a/sw/airborne/arch/lpc21/mcu_periph/sys_time_arch.c
+++ b/sw/airborne/arch/lpc21/mcu_periph/sys_time_arch.c
@@ -87,7 +87,7 @@
                         AMI601_IT)
 
 
-void sys_time_init( void ) {
+void sys_time_arch_init( void ) {
   /* setup Timer 0 to count forever  */
   /* reset & disable timer 0         */
   T0TCR = TCR_RESET;
@@ -113,19 +113,6 @@ void sys_time_init( void ) {
 
   /* set first sys tick interrupt */
   T0MR1 = SYS_TIME_RESOLUTION_CPU_TICKS;
-
-  sys_time.nb_sec     = 0;
-  sys_time.nb_sec_rem = 0;
-  sys_time.nb_tick    = 0;
-
-  for (unsigned int i=0; i<SYS_TIME_NB_TIMER; i++) {
-    sys_time.timer[i].in_use     = FALSE;
-    sys_time.timer[i].cb         = NULL;
-    sys_time.timer[i].elapsed    = FALSE;
-    sys_time.timer[i].end_time   = 0;
-    sys_time.timer[i].duration   = 0;
-  }
-
 }
 
 
diff --git a/sw/airborne/arch/sim/mcu_periph/sys_time_arch.c b/sw/airborne/arch/sim/mcu_periph/sys_time_arch.c
new file mode 100644
index 0000000000..d516657fed
--- /dev/null
+++ b/sw/airborne/arch/sim/mcu_periph/sys_time_arch.c
@@ -0,0 +1,28 @@
+/*
+ *
+ * Copyright (C) 2009-2011 The Paparazzi Team
+ *
+ * This file is part of paparazzi.
+ *
+ * paparazzi is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * paparazzi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with paparazzi; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "mcu_periph/sys_time.h"
+
+
+void sys_time_arch_init( void ) {
+
+}
diff --git a/sw/airborne/arch/sim/mcu_periph/sys_time_arch.h b/sw/airborne/arch/sim/mcu_periph/sys_time_arch.h
new file mode 100644
index 0000000000..634c9aa5d7
--- /dev/null
+++ b/sw/airborne/arch/sim/mcu_periph/sys_time_arch.h
@@ -0,0 +1,48 @@
+/*
+ *
+ * Copyright (C) 2009-2011 The Paparazzi Team
+ *
+ * This file is part of paparazzi.
+ *
+ * paparazzi is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2, or (at your option)
+ * any later version.
+ *
+ * paparazzi is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with paparazzi; see the file COPYING.  If not, write to
+ * the Free Software Foundation, 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ *
+ */
+
+/*
+ *\brief simulator dummy timing functions
+ *
+ */
+
+#ifndef SYS_TIME_ARCH_H
+#define SYS_TIME_ARCH_H
+
+#include <unistd.h>
+
+#define CPU_TICKS_OF_SEC(x) (x)
+#define SIGNED_CPU_TICKS_OF_SEC(x) (x)
+
+#define SEC_OF_CPU_TICKS(st) (st)
+#define MSEC_OF_CPU_TICKS(st) (st)
+#define USEC_OF_CPU_TICKS(st) (st)
+
+#define SysTimeTimerStart(_t) { }
+#define SysTimeTimer(_t) (_t)
+#define SysTimeTimerStop(_t) { }
+
+
+static inline void sys_time_usleep(uint32_t us) {}
+
+#endif /* SYS_TIME_ARCH_H */
diff --git a/sw/airborne/arch/stm32/mcu_periph/sys_time_arch.c b/sw/airborne/arch/stm32/mcu_periph/sys_time_arch.c
index 5db659944e..a9582a3015 100644
--- a/sw/airborne/arch/stm32/mcu_periph/sys_time_arch.c
+++ b/sw/airborne/arch/stm32/mcu_periph/sys_time_arch.c
@@ -27,7 +27,7 @@
 #include "led.h"
 #endif
 
-void sys_time_init( void ) {
+void sys_time_arch_init( void ) {
 
   /* Generate SysTick interrupt every SYS_TIME_RESOLUTION_CPU_TICKS
    * The timer interrupt is activated on the transition from 1 to 0,
@@ -38,19 +38,6 @@ void sys_time_init( void ) {
 
   /* Set SysTick handler priority */
   NVIC_SetPriority(SysTick_IRQn, 0x0);
-
-  sys_time.nb_sec     = 0;
-  sys_time.nb_sec_rem = 0;
-  sys_time.nb_tick    = 0;
-
-  for (unsigned int i=0; i<SYS_TIME_NB_TIMER; i++) {
-    sys_time.timer[i].in_use     = FALSE;
-    sys_time.timer[i].cb         = NULL;
-    sys_time.timer[i].elapsed    = FALSE;
-    sys_time.timer[i].end_time   = 0;
-    sys_time.timer[i].duration   = 0;
-  }
-
 }
 
 
diff --git a/sw/airborne/mcu_periph/sys_time.c b/sw/airborne/mcu_periph/sys_time.c
index f8ebe22266..e2900d9e8a 100644
--- a/sw/airborne/mcu_periph/sys_time.c
+++ b/sw/airborne/mcu_periph/sys_time.c
@@ -61,3 +61,19 @@ void sys_time_update_timer(uint8_t id, uint32_t duration) {
   sys_time.timer[id].duration = duration;
   mcu_int_enable();
 }
+
+void sys_time_init( void ) {
+  sys_time_arch_init();
+
+  sys_time.nb_sec     = 0;
+  sys_time.nb_sec_rem = 0;
+  sys_time.nb_tick    = 0;
+
+  for (unsigned int i=0; i<SYS_TIME_NB_TIMER; i++) {
+    sys_time.timer[i].in_use     = FALSE;
+    sys_time.timer[i].cb         = NULL;
+    sys_time.timer[i].elapsed    = FALSE;
+    sys_time.timer[i].end_time   = 0;
+    sys_time.timer[i].duration   = 0;
+  }
+}
diff --git a/sw/airborne/mcu_periph/sys_time.h b/sw/airborne/mcu_periph/sys_time.h
index e25fa87a12..f83be3b34a 100644
--- a/sw/airborne/mcu_periph/sys_time.h
+++ b/sw/airborne/mcu_periph/sys_time.h
@@ -108,5 +108,8 @@ static inline bool_t sys_time_check_and_ack_timer( uint8_t id ) {
 
 #include "mcu_periph/sys_time_arch.h"
 
+/* architecture specific init implementation */
+extern void sys_time_arch_init(void);
+
 
 #endif /* SYS_TIME_H */