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I know there are similar posts to this I am just looking to see if there are any new more efficient solutions. I have a MCU and I am looking to add a circuit in between the power supply and the MCU that can force a power-cycle after X seconds/hours.

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closed as too broad by The Photon, Dave Tweed Oct 11 '17 at 11:49

Please edit the question to limit it to a specific problem with enough detail to identify an adequate answer. Avoid asking multiple distinct questions at once. See the How to Ask page for help clarifying this question. If this question can be reworded to fit the rules in the help center, please edit the question.

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    \$\begingroup\$ Any more efficient solution would be a dedicated IC. You can Google "watchdog timer IC" to find examples. Specific recommendations are off topic thought. \$\endgroup\$ – The Photon Oct 10 '17 at 1:00
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    \$\begingroup\$ Many microcontrollers include a "watchdog timer" that can be enabled by software. The watchdog timer will cause a reset if not kicked occasionally. \$\endgroup\$ – Peter Bennett Oct 10 '17 at 1:15
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    \$\begingroup\$ What does the 555 solution cost you and can you then define what you mean by "cost effective." How inefficient is the 555 and what would you call "efficient," by comparison? Give us some numbers here. \$\endgroup\$ – jonk Oct 10 '17 at 4:01
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    \$\begingroup\$ @Transistor (1) I don't know of any that accept only windowed kicks. (2) Many of them are tied to the MCU clock (should have their own separate clock.) (3) Many don't actually reset the MCU, but just issue an NMI of sorts. (4) Many are maskable in software and can be repurposed as a timer; external ones are always active. (5) They don't reset external hardware (which may be appropriate.) (6) External ones often support a much wider designable timing range. (7) External ones can support different timing for reset vs normal operation, instead of "disabled until ready to go" with internal ones. \$\endgroup\$ – jonk Oct 10 '17 at 6:46
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    \$\begingroup\$ At this point, its no longer a high level question on what type of device does what you want, but a product recommendation. You have the name of the two types of chips that do what you want, and an option to roll your own MCU solution. \$\endgroup\$ – Passerby Oct 11 '17 at 0:09
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These are called watchdogs. They come as dedicated external ICs and have a variety of functions and features. Sometimes they also have low voltage monitoring.

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    \$\begingroup\$ ...and also on most MCUs as built in internal functionality. Typically there's a brownout detector, too. \$\endgroup\$ – Chris Stratton Oct 10 '17 at 2:21
  • \$\begingroup\$ Can these ICs detect when a script on the main system has failed? I am not sure what the full scope of functionality is built into a watchdog IC \$\endgroup\$ – SChand Oct 10 '17 at 5:39
  • \$\begingroup\$ @SChand -- yes, you reset the watchdog timer in your main loop. If it doesn't update, then the watchdog will restart the MCU. \$\endgroup\$ – Wesley Lee Oct 10 '17 at 5:42
  • \$\begingroup\$ @WesleyLee I see how the SW watchdog is useful but I need a system independent of the MCU. I was thinking of using a 555 timer but not sure if that is my best option \$\endgroup\$ – SChand Oct 10 '17 at 21:34

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