Dell watchdog timer utility7/3/2023 ![]() ![]() You might then be able to go back and optimise the design later on once that initial pressure to release has subsided, but it's more common than you might think (or want) to effectively throw money at the first version of a product, because not getting it into market quickly might cost the company far more than what they're losing per item on the extra hardware they're shipping. Or even if you are working on a high volume product where shaving even a few pence/cents/etc off the cost would be beneficial, you might also be up against a stupidly tight deadline which means you have to do whatever it takes to get something out the door ASAP. if you're working on a low volume high cost product where time spent on optimising the BOM cost and trying out new design ideas rather than just sticking with what you know will work and get the product up and running and out the door sooner rather than later, isn't going to be repaid through increased profit margins. Don't quote me on that though, I've not done any designs that fall into these categories, I just have a vague recollection of hearing this mentioned during a seminar or somesuch.Īnd sometimes designers just do stuff because it's how they're used to doing it, and the nature of the design means the added cost of fitting an external watchdog isn't important - e.g. IIRC, some safety critical designs require the watchdog to meet certain criteria, which aren't always provided by the internal watchdogs. And something has to protect the machine, if possible. This is problematic when you're running a multi kilowatt temperature control system. ![]() In the machine, where the power is noisy, tcp/ip problems have caused the comm system to freeze with no recovery. On the bench, the controller runs hundreds of thousands of requests without an error, and every error recovers elegantly. I've had issues running an RTOS with a tcp/ip stack hanging. Even if your MTBF is 14 years in a machine that only lasts 5 years, you can't release something that could cause a catastrophic error without a failsafe. MTBFs don't really matter here, in my opinion. Third party library has an unrecoverable error. A long read function overwrites a return vector Function requiring input from another machine fails because the other machine fails. I wanted to understand how big a concern is it for iot devices which are supposed to run 24*7 with a life expectancy of atleast 5 years. And these things can be mitigated by writing a better firmware in my opinion.Īnother thing I came across is bit flips caused by cosmic rays. If I have an independent watchdog timer like in my case (I'm using STM32L4 series mcu), what could be the reasons which should make me include an external watchdog ?Īlso, I read that main causes for the device misbehaving can be attributed to memory errors or stack overflow. Given the fairly advance mcu, what should be athe reason to use a watchdog in a system ? Good thing in my case is that the watchdog runs via LSI which is independent of the main system clock. Use internal watchdog which is available in the mcu I'm using. ![]() So, I'm laying it out here and hope to get more clarity on the subject. I was weighing my option to include a watchdog timer.Īfter researching about the topic, I'm even more confused about it. I am working on a design for a telematics device. General question: any question that is not technicalĪfter your question is answered, please change the flair to "Resolved".(*) At mods' discretion, certain self-promotion submissions from people who contribute to this sub in other ways may be allowed and tagged with the "Self-promo" flairĬomplete rules: /r/embedded/about/rules/ Link flairsĪfter posting a submission, please select a flair: No memes (pictures with superimposed text), shit posts.No spam no commercial posts, links to commercial pages (including crowd funding sites), no employment ads (job offers and requests go to the weekly thread), no self-promotion (*).If asking a question, ask the actual question, fully yet concisely, right in the title.Be civil: do not insult no all-caps, no excessive "!" and "?", please.Questions on employment (career, internship), education (major, certificates), how to start in embedded.Job announcements (outside the monthly job thread).High level software (e.g., C#, Javascript): r/softwaredevelopment, r/software.Single Board computers: r/Raspberry_pi, r/Arduino, r/linux_devices, r/linuxboards.Hardware design that does not include a micro for electronic circuits: /r/AskElectronics.Homework help but make it clear it's homework. ![]() This sub is dedicated to discussion and questions about embedded systems: "a controller programmed and controlled by a real-time operating system (RTOS) with a dedicated function within a larger mechanical or electrical system, often with real-time computing constraints." FAQ ![]()
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