a UI task) is using so many CPU cycles that lower priority tasks (like a WiFi task) never get to run preventing sensor data from being published to your cloud service. One or more tasks become deadlocked because mutexes were grabbed in the wrong order or weren’t released.A hardware component (such as a HRM, Accelerometer, or NOR Flash Chip) is wedged and not.Memory gets corrupted and code winds up in an infinite loop.Some of the most common I’ve run into over the There are numerous ways an embedded device can hang. Usually “fed” by toggling a GPIO line from the MCU being monitored. NOTE: It also worth mentioning that for some systems where catching system hangs is missionĬritical, there are even dedicated ICs which can be used 2. The rationale here is if software is unable to reset the watchdog counter, the system is not running as expected and needs to be reset to get back to a sane state. This operation is usually referred to as “feeding”, “kicking”, or “patting” the dog. Once enabled, the system software needs to reset the counter periodically to prevent the device from rebooting. The peripheral is typically disabled by default and it’s the programmers responsibility to configure and enable it in software. When the count reaches zero, the hardware will automatically reset the device. This peripheral is comprised of a counter which decrements automatically by the hardware each clock cycle. Most chip vendors include an isolated RTL block known as a “Watchdog Timer” in a MCU. Using GDB Python to prevent Software Watchdog Misfires.Configuring the NRF52 Hardware Watchdog.Examining the NRF52840 Hardware Watchdog Behavior.Enabling a Hardware Watchdog in a System.How do I find out if a watchdog reset took place?.What happens when the watchdog expires?.How does the watchdog behave with a debugger?.When does the watchdog configuration get reset?.Threading.Timer, Threading.Timer is the way to go. However, if this is not the case, and it's down to Thread.Sleep vs. The locking should prevent the timer callback from trying to free the timer prior to the Timer field having been set.Īddendum: As the commenter pointed out, if action() does something with the UI, then using a is probably a better bet, since it will run the callback on the UI thread. State.Timer = new Timer((callbackState) => and to start the timer: TimerState state = new TimerState() Maybe something like this? (Again, haven't actually tried it) class TimerState Granted, Timer is still not going to be exactly accurate, but the intent is to fire the callback as close to the specified time as possible, whereas this is NOT necessarily the intent of Thread.Sleep.Īs for destroying the Timer, the callback can accept a parameter, so you may be able to pass the Timer itself as the parameter and call Dispose in the callback (though I haven't tried this - I guess it is possible that the Timer might be locked during the callback).Įdit: No, I guess you can't do this, since you have to specify the callback parameter in the Timer constructor itself. It also may be more accurate, since Thread.Sleep is only guaranteed to wait at LEAST as long as the amount of time you specify (the OS may put it to sleep for much longer). In other words, Timer is going to be much more efficient. If you need this to happen more than once during the life of your application, this will save the overhead of creating and destroying a bunch of threads (a process which is very resource intensive, as the article you reference points out), since it will just reuse threads in the pool, and if you will have more than one timer going at once it means you will have fewer threads running at once (also saving considerable resources). One difference is that dispatches the callback on a thread pool thread, rather than creating a new thread every time.
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