Update main.c

Add Main function

main.c

@@ -25,3 +25,12 @@ void delay(int us)
     while ((STCTRL & (1 << 16)) == 0);          // Wait until flag is set
     STCTRL &= ~ENABLE;                          // Stop the timer
 }
+
+int main(void) 
+{
+    systick_setting(); // SysTick setup
+    while (1) 
+    {
+      
+    }
+}