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Jack ganssle watchdog backup

Toggle the WDT input too slowly, too fast, or not at all, and a timeout will occur. Since a crashed program will likely speed up or bog down if it does anything at all, errant strobing of the tickle bit will almost certainly be outside the time band required. Even if wandering code issues output instructions their potentially scrambled little brains will be straightened out. In other words, a healthy dose of paranoia leads to better systems. It's fun to watch a multitasking product crash - the entire system might be hung, but one task still responds to interrupts.

  • Watchdog Hackaday
  • Designing Great Watchdog Timers for Embedded Systems

  • Great Watchdog Timers For Embedded Systems, by Jack Ganssle . Maybe a pacemaker needs to reboot in a heartbeat (so to speak) or maybe backup. Jack Ganssle believes that embedded development can be much more efficient than it The 's built-in watchdog timer hardware was not used, over the . needs to reboot in a heartbeat (so to speak) or maybe backup hardware should​. Parameter Backup Prior to Watchdog System Reset Jack Ganssle.

    The Enhanced Watchdog Timer (WDT) runs independent of the rest of the system.
    Design the logic so the jumper disconnects the WDT from the reset line possibly though an inverter so an inserted jumper sets debug mode.

    Video: Jack ganssle watchdog backup EEVblog #818 - Embedded Electronics With Jack Ganssle

    November 24, Stephen Evanczuk. The responses were varied, ranging from "Freak! Either handle these competently or initiate a WDT timeout.

    Watchdog Hackaday

    This tells the story of a failed Clementine spacecraft mission that could have been saved by a watchdog, and elaborates on the design and implementation of watchdog techniques.

    Design house plucks means
    They function as failsafes to reset the device in case of a software failure. The CPU halts, staying halted till a reset, and only a reset, comes along.

    Video: Jack ganssle watchdog backup STM32L4 training: 06.7 Timers - Independent Watchdog (IWDG) theory

    It lets you add functions to a queue of jobs, along with data about when they should be run. The Itanium 2 processor, also sporting an astronomical transistor budget and small geometry, includes an on-board system management unit to handle transient hardware failures.

    In other words, it appears the code ran wild, firing thrusters it should never have enabled; they kept firing till the tanks ran nearly dry and the hardware reset closed the valves.

    Here's my take. However, in systems that must use the internal versions, there's plenty we can do to make them more reliable.

    A Designer's Guide to Watchdog Timers. By Jack Ganssle. Contributed By Convergence Promotions LLC. A watchdog timer (WDT) is a bit of. Although a watchdog timer is essential to reliability, a vulnerable dog does not a January 15, Jack Ganssle Maybe a pacemaker needs to reboot in a heartbeat (so to speak)-or maybe backup hardware should issue a few ticks if.

    Watchdog timers are an often overlooked feature of microcontrollers. They function In this oldie-but-goodie, [Jack Ganssle] provides us with a great write up on watchdog timers. This tells the In such cases, some kind of backup is needed.
    But it does offer a very intriguing feature. Surely the customers were irritated, and the possible future sales of that company at least somewhat diminished.

    images jack ganssle watchdog backup

    Pure software implementations are simply not reliable. Not surprisingly, the software team wished they had indeed used the watchdog timer, and had not implemented the thruster timeout in firmware.

    images jack ganssle watchdog backup

    It's external to the CPU, shares no resources, and is utterly simple, thus devoid of latent defects. The WDT cannot be disabled once enabled -- good thinking, folks! A watchdog that runs once a second will miss tasks that start only hourly.

    Encapsulation solves that problem, but not the one of a wandering pointer walking over the data, or of a latent reentrancy issue corrupting things. Call watchdog routine B, which makes sure state is now 0x88DD.

    Designing Great Watchdog Timers for Embedded Systems

    Almost Done. Now redesign the watchdog task to run in one of two modes. Set state to zero.

    Author: Negal

    4 thoughts on “Jack ganssle watchdog backup

    1. The CPU halts, staying halted till a reset, and only a reset, comes along. Some CPUs, notably the 68k and ColdFire, will throw an exception if a software crash causes the stack pointer to go odd.

    2. November 20, Gina Roos. It's entirely possible that a bit of energy from starting the fan's highly inductive motor will alter the port's setting.