You can sum it all up into this; The problem is completely solved by using a battery and having acpid installed. Except you need a way to completely disconnect power, from the BBB's input, for a single, or perhaps two corner cases that would otherwise require a hard reset.
All these fancy high cost solutions are honestly ridiculous, and if you can just use an OTS UPS . . . On Mon, May 16, 2016 at 2:55 PM, Super Twang <[email protected]> wrote: > > > Hey y'all (yes, I'm in Texas), > > I have really appreciated all of the good ideas and thoughtful design > ideas here. There are some apples and oranges being discussed at times > because the problem of BBB reliability is not single-fold. In the hopes of > providing a clearer "Big picture" of the issue, as well as to summarize > some of my own research on the topic, I've attempted to capture the main > points in this thread into an outline format. If it is convenient, you can > refer to specific problems/solutions/caveats by the outline number, ie ( > III.A.1 ) in any subsequent discussions -- this kind of shorthand might > clarify the issues that are being discussed, rather than having to spell > this stuff out (or omit it) when talking about a point. > > Is there a good spot on a WIKI for this somewhere? > > Enjoy, and thank you! > > ST > -------------------- DOCUMENT IS BELOW HERE > > > *SUMMARY BBB RELIABILITY PROBLEMS & FIXES:* > > > *I. Problems:* > > *A. System/Client Software Problems:* > * 1. Problem: Incomplete system/client sw startups ( why? -- can damage > result with this? )* > > * 2. Problem: Incomplete system/client sw shutdown* > > * a. Can cause system corruption* > > * 3. Client or system software freeze-up (it can happen!)* > > * a. Can freeze device operation even in absence of power issues* > > > *B. Hardware Problems:* > > * 1. Problem: BBB doesn't always restart without a hard-disconnect of > power (known hardware issue)* > > * a. Always - when shutdown/halted (ie shutdown/halt)* > * b. Sometimes - when hard cycled (ie power removed, reset button > pushed)* > > *C. Power problems* > > * 2. Problem: Mains power can't be relied upon* > > * a. Power loss (ie blackouts)* > * b. Partial power loss (ie brownouts)* > > > *II. Requirements:* > > * A. A "Reliability System" to address above problems. * > > *III. Needs:* > > * A. Backup power source for* > > * 1. BBB until complete shutdown* > * 2. Additional components of reliability system* > > * B. Hard-Reset Circuit: to completely remove, and re-add power to the > board (for I.B.1 above)* > > * C. Sensing: Need to detect* > > * 1. Power off: both presence and duration (ie detect/differentiate > I.C.2.a and I.C.2.b)* > * 2. System soft-freeze up (detect I.A.3)* > * 3. Power on: both present, and "Good" (ie good enough for full > reboot + protected powerdown)* > > * D. State Machine to enforce guaranteed order, no matter what* > > * 1. "Protected Shutdown": Complete shutdown after it has been > initiated* > > * a. even if power up is specified during shutdown (in which case > protected startup begins thereafter)* > > * 2. "Protected startup": Complete startup once it has been initiated* > > * a. even if power is removed during startup (in which case > protected shutdown follows)* > > * 3. "Power Good" before Startup: Power remains detached until enough > backup power for Protected Startup + Protected Shutdown* > > * 4. "Complete" Power off after shutdown: Complete detachment of power > from BBB to solve (I.B.1)* > > * 5. Others?* > > > > *IV. Solution Design Components/Approaches* > > * A. Backup power* > > * 1. Li-po Battery backup * > > * a. Pros:* > * i. Long lasting* > * ii. Relatively simple circuitry to support* > * iii. Greatest capacity* > > * b. Cons:* > * i. "Dangerous", thus travel/shipping restrictions* > * ii. Limited recharge cycles* > > * 2. Super capacitor-based Backup Power* > > * a. Pros:* > * i. No practical recharge cycle-limit* > * ii. "Safe" enough for restrition-free transport/shipping* > > * b. Cons:* > * i. Increased circuit complexity, esp for 2-cell systems needed to > produce 5v* > > > * 3. Coin-cell (to power Reliability System only)* > * a. Pros:* > * i. Cheap* > * ii. Long-lasting (10+ years)* > * iii. "Safe"* > * b. Cons:* > * i. Only powers reliability system, need additional solution > for BBB* > > > * B. Hard Reset Circuit (Pretty well known problem with solutions out > there)* > > * 1. Relay (physical, or solid state)* > * 2. Some kind of transistor switch* > > * C. Sensing* > > * 1. Mains Power off* > * a. Voltage comparator of some sort* > > * 2. System "Soft-freeze"* > > * a. BBB On-board software-controlled watchdog timer initiates > reboot* > > * 3. System initiated shutdown* > * a. GPIO pin connected to Reliability System, change state on > start* > > * 4. System completed shutdown * > * a. heuristic delay after final GPIO pin state change on end > (from IV.C.3.a just above)* > > * 5. System initiated startup* > * a. Implied action on "Power Good" (add'l sensing not needed)* > > * 6. System completed startup* > * a. GPIO pin connected to Reliability System changes state on > "Startup complete"* > > * 7. Mains Power On* > * a. Voltage comparator of some sort * > > * 8. Mains Power "Good" (enough backup power available for Protected > Startup + Protected Shutdown* > > > * D. State Machine* > > * 1. An MCU of some sort* > > * a. MSP430 series (William Herman/Wulfmans's recs)* > * i. Pros: * > * * very low power + coin cell battery == >10 years backup > life* > * * onboard ADC for voltage measurement/sensing* > * * inexpensive* > > * b. ST Micro series (ie STM8)* > > * c. NXP's LPC800 series* > > * 2. Discrete logic state machine* > > * a. Pros* > * i. More tolerant of brownouts(?) than unprotected MCU* > > * b. Cons* > * i. Lots of soldering! * > > * 3. Hybrid Technology - Programmable Mixed Mode Circuits* > > * a. Silego GreenPak (John3909's rec)* > > * i. Pros* > * * Nice dev kit ( < $60 )* > * * Very inexpensive ( < $0.40 )* > * * More tolerant of brownouts(?) than unprotected MCU > (John can you comment on this?)* > > > *V. Commercially Available Solutions* > > * A. Andice Labs Power Cape (Available for BBB/RaspberryPi)* > * http://andicelabs.com/beaglebone-powercape/ > <http://andicelabs.com/beaglebone-powercape/>* > * Li-Po Battery Backup, with software readable battery voltage and > current* > * ~ $65 (with headers) * > > > * B. Juice4Halt (Built for RaspberryPi, not BBB, but could be > repurposed, one would assume)* > * http://juice4halt.com <http://juice4halt.com>* > * Dual Super-capacitor Backup, with State Machine implemented* > * ~ $85 (5V, all told shipped to US)* > > * C. Others?* > > > > > > -- > For more options, visit http://beagleboard.org/discuss > --- > You received this message because you are subscribed to the Google Groups > "BeagleBoard" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected]. > To view this discussion on the web visit > https://groups.google.com/d/msgid/beagleboard/a3163a27-66e2-4efd-af37-aa92414fb01e%40googlegroups.com > <https://groups.google.com/d/msgid/beagleboard/a3163a27-66e2-4efd-af37-aa92414fb01e%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. 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