diff --git a/Makefile-ARM b/Makefile-ARM
index dd735f0..2d0a6ac 100644
--- a/Makefile-ARM
+++ b/Makefile-ARM
@@ -98,7 +98,7 @@ TARGET = $(PROGRAM).hex
 # Until the generic ARM port is completed, we'd have to wrap all sources
 # in #ifdef __AVR__. To avoid this, build only a selection for now:
 SOURCES  = mendel.c cpu.c serial.c sermsg.c sersendf.c delay.c
-SOURCES += gcode_parse.c gcode_process.c pinio.c timer.c
+SOURCES += gcode_parse.c gcode_process.c pinio.c timer.c clock.c
 ifeq ($(MCU), lpc1114)
   SOURCES += cmsis-system_lpc11xx.c
 endif
diff --git a/clock.c b/clock.c
index 02c8f8d..e003ec7 100644
--- a/clock.c
+++ b/clock.c
@@ -71,7 +71,11 @@ void clock_tick(void) {
 	called from clock_10ms(), do not call directly
 */
 static void clock_250ms(void) {
+  #ifndef __ARMEL_NOTYET__
   if (heaters_all_zero()) {
+  #else
+  if (1) {
+  #endif /* __ARMEL_NOTYET__, ! __ARMEL_NOTYET__ */
 		if (psu_timeout > (30 * 4)) {
 			power_off();
 		}
@@ -114,7 +118,9 @@ static void clock_10ms(void) {
 	// reset watchdog
 	wd_reset();
 
+  #ifndef __ARMEL_NOTYET__
 	temp_sensor_tick();
+  #endif /* __ARMEL_NOTYET__ */
 
 	ifclock(clock_flag_250ms) {
 		clock_250ms();
diff --git a/mendel.c b/mendel.c
index 05e3a22..dc972e6 100644
--- a/mendel.c
+++ b/mendel.c
@@ -44,8 +44,8 @@
 #include	"analog.h"
 #endif /* __ARMEL_NOTYET__ */
 #include	"pinio.h"
-#ifndef __ARMEL_NOTYET__
 #include	"clock.h"
+#ifndef __ARMEL_NOTYET__
 #include	"intercom.h"
 #include "spi.h"
 #include "sd.h"
@@ -222,8 +222,8 @@ int main (void)
 
       #endif /* CANNED_CYCLE */
 		}
+    #endif /* __ARMEL_NOTYET__ */
 
 		clock();
-    #endif /* __ARMEL_NOTYET__ */
 	}
 }
diff --git a/timer-arm.c b/timer-arm.c
index 39158ca..3c88df0 100644
--- a/timer-arm.c
+++ b/timer-arm.c
@@ -8,6 +8,7 @@
 #if defined TEACUP_C_INCLUDE && defined __ARMEL__
 
 #include "cmsis-core_cm0.h"
+#include "clock.h"
 
 
 /** Timer initialisation.
@@ -53,8 +54,8 @@ void timer_init() {
 */
 void SysTick_Handler(void) {
 
-  #ifndef __ARMEL_NOTYET__
   clock_tick();
+  #ifndef __ARMEL_NOTYET__
   dda_clock();
   #endif /* __ARMEL_NOTYET__ */
 }