Diff: FixedRefresh.hpp

Revision:

6:076fcae78bac

diff -r e00cc0dab1c7 -r 076fcae78bac FixedRefresh.hpp
--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/FixedRefresh.hpp	Wed Jun 29 19:04:28 2016 +0000
@@ -0,0 +1,51 @@
+/**
+ * @file FixedRefresh.hpp
+ * @author Weimen Li
+ * @date June 26th, 2016
+ * @class FixedRefresh
+ * @brief This class is used in an RTOS to ensure that iterations of a loop happen at fixed time intervals,
+ * regardless of how long other code in the loop takes. In doing so, it waits the thread that is currently
+ * running to allow other threads to run.
+ */
+
+/*
+ * FixedRefresh.hpp
+ *
+ *  Created on: Jun 26, 2016
+ *      Author: Developer
+ */
+
+#ifndef FIXEDREFRESH_HPP_
+#define FIXEDREFRESH_HPP_
+#include "mbed.h"
+#include "rtos.h"
+
+class FixedRefresh {
+public:
+    /// Constructor for the FixedRefresh class.
+    FixedRefresh();
+    /// Destructor for the FixedRefresh class.
+    virtual ~FixedRefresh();
+
+    /*
+     * @brief Function which ensures as much as possible that micros microseconds elapses
+     * between successive calls, no matter how long the computation beforehand took.
+     * @args micros The number of microseconds that should elapse between successive calls.
+     * @returns false if waiting will not occur because greater than micros microseconds has
+     * elapsed since the previous calls. If the function does return false, then your computation
+     * is taking too much time.
+     */
+    bool refresh_us(uint32_t micros);
+private:
+    /// The number of microseconds to wait.
+    uint32_t wait_us;
+    Timer elapsedTime;
+    Timeout waitTimer;
+    /**
+     * @brief Mutex that is locked
+     */
+    Semaphore waitSemaphore;
+    void timerCallback();
+};
+
+#endif /* FIXEDREFRESH_HPP_ */