Watchdog.h

00001 /// @file Watchdog.h provides the interface to the Watchdog module
00002 ///
00003 /// This provides basic Watchdog service for the mbed. You can configure
00004 /// various timeout intervals that meet your system needs. Additionally,
00005 /// it is possible to identify if the Watchdog was the cause of any 
00006 /// system restart, permitting the application code to take appropriate
00007 /// behavior.
00008 /// 
00009 /// Adapted from Simon's Watchdog code from http://mbed.org/forum/mbed/topic/508/
00010 ///
00011 /// @note Copyright © 2011,2015 by Smartware Computing, all rights reserved.
00012 ///     This software may be used to derive new software, as long as
00013 ///     this copyright statement remains in the source file.
00014 /// @author David Smart
00015 ///
00016 /// History
00017 /// \li v2.00 - 20150315: Enhanced beyond TARGET_LPC1768 to TARGET_LPC4088, TARGET_STM
00018 /// \li v1.00 - 20110616: initial release with some documentation improvements
00019 ///
00020 #ifndef WATCHDOG_H
00021 #define WATCHDOG_H
00022 #include "mbed.h"
00023 
00024 /// The Watchdog class provides the interface to the Watchdog feature
00025 ///
00026 /// Embedded programs, by their nature, are usually unattended. If things
00027 /// go wrong, it is usually important that the system attempts to recover.
00028 /// Aside from robust software, a hardware watchdog can monitor the
00029 /// system and initiate a system reset when appropriate.
00030 ///
00031 /// This Watchdog is patterned after one found elsewhere on the mbed site,
00032 /// however this one also provides a method for the application software
00033 /// to determine the cause of the reset - watchdog or otherwise.
00034 ///
00035 /// Supports:
00036 /// \li TARGET_LPC1768 
00037 /// \li TARGET_LPC4088
00038 /// \li TARGET_STM
00039 ///
00040 /// example:
00041 /// @code
00042 /// Watchdog wd;
00043 ///
00044 /// ...
00045 /// main() {
00046 ///    if (wd.WatchdogCausedReset())
00047 ///        pc.printf("Watchdog caused reset.\r\n");
00048 ///      
00049 ///    wd.Configure(3.0);       // sets the timeout interval
00050 ///    for (;;) {
00051 ///         wd.Service();       // kick the dog before the timeout
00052 ///         // do other work
00053 ///    }
00054 /// }
00055 /// @endcode
00056 ///
00057 class Watchdog {
00058 public:
00059     /// Create a Watchdog object
00060     ///
00061     /// example:
00062     /// @code
00063     /// Watchdog wd;    // placed before main
00064     /// @endcode
00065     Watchdog();
00066     
00067     /// Configure the timeout for the Watchdog
00068     ///
00069     /// This configures the Watchdog service and starts it. It must
00070     /// be serviced before the timeout, or the system will be restarted.
00071     ///
00072     /// example:
00073     /// @code
00074     ///     ...
00075     ///     wd.Configure(1.4);  // configure for a 1.4 second timeout
00076     ///     ...
00077     /// @endcode
00078     ///
00079     /// @param[in] timeout in seconds, as a floating point number
00080     /// @returns none
00081     ///
00082     void Configure(float timeout);
00083     
00084     /// Service the Watchdog so it does not cause a system reset
00085     ///
00086     /// example:
00087     /// @code
00088     ///    wd.Service();
00089     /// @endcode
00090     /// @returns none
00091     void Service();
00092     
00093     /// WatchdogCausedReset identifies if the cause of the system
00094     /// reset was the Watchdog
00095     ///
00096     /// example:
00097     /// @code
00098     ///    if (wd.WatchdogCausedReset())) {
00099     /// @endcode
00100     ///
00101     /// @returns true if the Watchdog was the cause of the reset
00102     bool WatchdogCausedReset();
00103 private:
00104     bool wdreset;
00105 };
00106 
00107 #endif // WATCHDOG_H