I'll try again soon with my more stable circuit (*soldered), also with RX disconnected so I just get output from the Pocket Beagle and the only power input is from the battery circuit.
(*Soldered, so no loose breadboard connections, better current carrying capacity, etc.) What is a good way to share log files? Mine can get verbose! I could store it somewhere and post a link - suggestions welcomed! I have a lot of possibilities, but just let me know what works best for you. On Tuesday, August 28, 2018 at 12:51:23 PM UTC-7, Fred Kerr wrote: > > Yes, it ran quite a lot longer on the 1F, but still hung. > > I wired this up (see pic) to be more stable than the breadboard mess I > had. The led on 1.8k resistor is gonna run a lot longer than I'll take at > lunch!!! > > Can I isolate RX and TX or...oh I just need TX from the beagle for > visibility! > > 1F 5.5v supercap (that battery was discharged to 3.96v). This one has more > charge. Also put a 1000uf electrolytic on the soldered version, "because". > > Fred Kerr (mobile) > > On Tue, Aug 28, 2018, 12:13 PM Jason Kridner <[email protected]> wrote: > >> >> >> On Monday, August 27, 2018 at 11:15:36 PM UTC-4, Fred Kerr wrote: >>> >>> Hello all, >>> >>> I'm being just a little bit careful here: >>> >>> I'm about to try this, but I will connect up the serial terminal first, >>> so I can see output and interact with the board. (Graceful shutdown!) >>> >> >> Don't connect the power or RX (ie., serial cable to PocketBeagle) signals >> to avoid them interfering. Great thing to monitor. >> >> >>> >>> I will test the serial connection first with just a micro USB charging >>> cable rather than USB to a computer. (Simplify!) >>> >> >> Not sure what you are testing here. Are you just saying you'll power via >> the microUSB connection and not connect to a computer, just to see the >> behavior? You are monitoring with a serial connection? >> >> >>> >>> It's my understanding that LiPo charging is disabled or not present in >>> the firmware. (I'll give you the "uname -a" and other info the next time I >>> fire it up. Just let me know what and how to check.) >>> >> >> It is not enabled by default. There is a flag in the PMIC that needs to >> be enabled. We've been playing with a driver to set the flag, but there are >> other bugs in that driver not related to actually charging. >> >> >>> >>> Also, it's not clear (without reading the data sheet :) ) about the >>> resistor values for the thermistor and the parallel (linearizing?) resistor. >>> >>> If you have a 10K thermistor, do you put it in parallel with a 10K >>> resistor, or likewise 100K thermistor in parallel with a 100K resistor? Do >>> you put the thermistor anywhere in contact with the (e.g., 18650) LiPo? >>> >> >> Looking at the TPS65217 datasheet says to put a 75kohm resistor in >> parallel. >> >> I'm not sure, but I believe the actual thermal resistor should be >> something like >> https://www.ametherm.com/blog/thermistors/thermistors-ntc-thermistor-temperature-sensors-provide-li-ion-battery-safety/ >> . >> >> >>> >>> From the prior thread, it seems to be sufficient (if even necessary) >>> just to connect a 10K resistor from TS (P2-16) to ground (P2-15). >>> >> >> Yes, that is supposed to work, ignoring the battery temperature. >> >> >>> >>> 10uF cap from battery (P2-14) to ground (P2-15). >>> >>> (Tangent/future: What about larger cap, perhaps using a 5.5V supercap, >>> detect supercap discharging (lipo voltage to ~min input voltage on vbat) >>> and give an interrupt to shut the board down?) >>> >>> >>> Thanks in advance for your help, and to the original thread authors! >>> >>> >>> Other posts that I found: >>> >>> Safely power down the PocketBeagle supplied by a battery (no replies?): >>> https://groups.google.com/d/msg/beagleboard/dDSD89DGzpU/j2WzZyA2CgAJ >>> >> >> I threw in a reply. >> >> >>> >>> >>> Supplying two ICs from the PocketBeagle powered by a Lipo battery >>> https://groups.google.com/d/msg/beagleboard/B7Zyf97hvzY/z8cOt0MHBwAJ >>> >>> I want to do some excessive self-telemetry, both internal and external. >>> I plan to scale the raw battery voltage by 1/11 with an op amp before >>> feeding to one of the 1.8V ADC inputs. I'll defer to suggestions about >>> measuring current. >>> >>> (This is a tangent: I also plan to be paranoid if I connect to a car and >>> want to monitor the car's "12V" with something like a VCO on the car side >>> pulsing to an optoisolator, but I'm sure there are better ideas out there! >>> :) (I could use several PIC -> nrf24l01 for some "really good" isolation!) >>> >>> Thanks, >>> Fred Kerr >>> >>> On Friday, November 10, 2017 at 10:32:46 AM UTC-8, Adam Saenz wrote: >>>> >>>> Keep in mind that the 7V is Absolute Max voltage so you should operate >>>> below this level or risk damaging the chip. >>>> >>>> >>>> >>>> On Thursday, November 9, 2017 at 10:15:05 PM UTC-8, Shannon Mackey >>>> wrote: >>>>> >>>>> >>>>> I expect I'm overlooking something, But it isn't obvious to me how to >>>>> power the PocketBeagle with batteries. It doesn't have a similar >>>>> arrangement to BBB. Can someone point me in the right direction, please? >>>>> >>>>> Thanks! >>>>> >>>>> -- >> For more options, visit http://beagleboard.org/discuss >> --- >> You received this message because you are subscribed to a topic in the >> Google Groups "BeagleBoard" group. >> To unsubscribe from this topic, visit >> https://groups.google.com/d/topic/beagleboard/PQCNhmeBK3M/unsubscribe. >> To unsubscribe from this group and all its topics, send an email to >> [email protected]. >> To view this discussion on the web visit >> https://groups.google.com/d/msgid/beagleboard/846799d8-d0bf-481a-9599-cd3b97c1b065%40googlegroups.com >> >> <https://groups.google.com/d/msgid/beagleboard/846799d8-d0bf-481a-9599-cd3b97c1b065%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. 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