timer: add Timer class

Timer class consists of systack_handler functionality
with an internal timer for global counter in main()

Timer/inc/Timer.h

@@ -0,0 +1,75 @@
+/*
+ * Timer.h
+ *
+ *  Created on: Oct 14, 2022
+ *      Author: tylen
+ */
+
+#ifndef TIMER_H_
+#define TIMER_H_
+
+#include "board.h"
+#include <atomic>
+#include <climits>
+
+extern "C"
+{
+  /**
+   * @brief Handle interrupt from SysTick timer
+   * @return Nothing
+   */
+  void SysTick_Handler (void);
+}
+
+class Timer
+{
+public:
+  /**
+   * @brief Initalize the systick configuration with your frequency
+   *
+   */
+  Timer (uint32_t freq = 1000);
+  virtual ~Timer ();
+
+  /**
+   * @brief Tick the counter.
+   *
+   * Counter is incremented by one every tick,
+   * if it gets over the INT_MAX (see limits.h),
+   * the counter rolls up back to zero and starts
+   * over.
+   *
+   *
+   * @param ms Counter ticking frequency is provided in milliseconds
+   */
+  void tickCounter (int ms);
+
+  /**
+   * @brief Get the current counter value
+   *
+   * @return int counter value
+   */
+  int getCounter ();
+
+  /**
+   * @brief Set counter to 0.
+   *
+   */
+  void resetCounter ();
+
+  /**
+   * @brief Sleep for amount of time
+   *
+   * Time is either in ms or in sec, defined
+   * by systickInit_xx()
+   *
+   * @param ms milliseconds
+   */
+  void Sleep (int ms);
+
+private:
+  volatile std::atomic_int counter;
+  volatile std::atomic_int timer;
+};
+
+#endif /* TIMER_H_ */