diff --git a/Firmware/config.h b/Firmware/config.h
index a1014ca34..8bd1a16e2 100644
--- a/Firmware/config.h
+++ b/Firmware/config.h
@@ -8,5 +8,8 @@
 #define ADC_OVRSAMPL      16        //oversampling multiplier
 #define ADC_CALLBACK      adc_ready //callback function ()
 
+//SM4 configuration
+#define SM4_DEFDELAY      500       //default step delay [us]
+
 
 #endif //_CONFIG_H
diff --git a/Firmware/temperature.h b/Firmware/temperature.h
index 91791c4cf..b20a67cd6 100644
--- a/Firmware/temperature.h
+++ b/Firmware/temperature.h
@@ -27,6 +27,9 @@
   #include "stepper.h"
 #endif
 
+#define ENABLE_TEMPERATURE_INTERRUPT()  TIMSK0 |= (1<<OCIE0B)
+#define DISABLE_TEMPERATURE_INTERRUPT() TIMSK0 &= ~(1<<OCIE0B)
+
 // public functions
 void tp_init();  //initialize the heating
 void manage_heater(); //it is critical that this is called periodically.