diff --git a/Timer/inc/Timer.h b/Timer/inc/Timer.h
index 227f4a5..840d386 100644
--- a/Timer/inc/Timer.h
+++ b/Timer/inc/Timer.h
@@ -13,7 +13,7 @@
 #include <climits>
 
 static volatile std::atomic_int timer;
-static volatile unsigned int systicks = 0;
+static volatile std::atomic_int systicks;
 
 extern "C"
 {
@@ -24,8 +24,7 @@ extern "C"
   void SysTick_Handler (void);
 }
 
-uint32_t millis();
-
+uint32_t millis ();
 
 class Timer
 {
diff --git a/Timer/src/Timer.cpp b/Timer/src/Timer.cpp
index 0b93fe3..c66d9ea 100644
--- a/Timer/src/Timer.cpp
+++ b/Timer/src/Timer.cpp
@@ -25,6 +25,7 @@ Timer::Timer (uint32_t freq) : freq (freq)
   SysTick_Config (sysTickRate / freq);
   counter = 0;
   timer = 0;
+  systicks = 0;
 }
 
 Timer::~Timer ()