diff --git a/inc/pwmout.h b/inc/pwmout.h
--- a/inc/pwmout.h
+++ b/inc/pwmout.h
@@ -9,7 +9,7 @@
 
 
 void pwmout_init(void);
-void pwmout_process(uint16_t duty);
+void pwmout_process(int16_t duty);
 TIM_HandleTypeDef* pwmout_get_tim(void);
 
 #endif