diff --git a/src/hal.c b/src/hal.c
index 0c863410..45161647 100644
--- a/src/hal.c
+++ b/src/hal.c
@@ -137,16 +137,16 @@ void start_hal(){
 
    if(hal.frt_func_count > 0){
       start_frt();
-      TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE); // enable frt
+      enable_frt();
    }
-   TIM_Cmd(TIM2, ENABLE); // enable rt
+   enable_rt();
 }
 
 void stop_hal(){
    stop_frt();
    stop_rt();
-   TIM_ITConfig(TIM2, TIM_IT_Update, DISABLE); // disable frt
-   TIM_Cmd(TIM2, DISABLE); // disable rt
+   disable_frt();
+   disable_rt();
    for(; hal.rt_deinit_func_count > 0; hal.rt_deinit_func_count--){
       hal.rt_deinit[hal.rt_deinit_func_count - 1]();
    }
@@ -270,9 +270,6 @@ int link_hal_pins(HPNAME source, HPNAME sink){
   s = find_hal_pin(sink);
 
   if(d != 0 && s != 0){
-   //   if(s->source != s){
-   //      printf_("relink %s:%i -> %s:%i to %s:%i -> %s:%i\n", s->source->name, s->source, sink, s, source, d, sink, s);
-   //   }
     s->value = s->source->source->value;
     s->source = d;
 	return(1);
diff --git a/src/hal.h b/src/hal.h
index 48dfce67..fe7e66a1 100644
--- a/src/hal.h
+++ b/src/hal.h
@@ -18,9 +18,7 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
-#include "scanf.h"
-#include "printf.h"
-#include "stm32f4xx_conf.h"
+#include <stdint.h>
 
 #pragma once
 
@@ -153,6 +151,10 @@ int link_hal_pins(HPNAME source, HPNAME sink);
 
 void add_comp(struct hal_comp* comp);
 
+extern void enable_rt();
+extern void enable_frt();
+extern void disable_rt();
+extern void disable_frt();
 
 #define COMP(type)                  \
 {                                   \
diff --git a/src/main.c b/src/main.c
index f76c2f04..93e7ae5c 100644
--- a/src/main.c
+++ b/src/main.c
@@ -41,6 +41,20 @@ int __errno;
 volatile double systime_s = 0.0;
 void Wait(unsigned int ms);
 
+//hal interface
+void enable_rt(){
+   TIM_Cmd(TIM2, ENABLE);
+}
+void enable_frt(){
+   TIM_ITConfig(TIM2, TIM_IT_Update, ENABLE);
+}
+void disable_rt(){
+   TIM_Cmd(TIM2, DISABLE);
+}
+void disable_frt(){
+   TIM_ITConfig(TIM2, TIM_IT_Update, DISABLE);
+}
+
 //20kHz
 void TIM2_IRQHandler(void){
    TIM_ClearITPendingBit(TIM2,TIM_IT_Update);