e...@thyrsus.com said: > * an Anker 10-port powered USB hub, because Mark turned out to be > unsurpringly right that el cheapo unpowered hubs aren't stable > enough (ordered)
I'm missing something. What is that hub for? Are you using it to power all the Pi-s? USB provides 100 mA by default. A device can ask for up to 500 mA. It's supposed to ask/negotiate before it uses more than 100. It's supposed to be able to ask while only using 100 mA. If you have a 4 port hub, it can get 500 mA from the host, use up to 100 mA itself, and pass on 100 mA to each of the 4 downstream slots. You can get tiny meters that plug into a USB chain to measure the current. Beware, they will reduce the voltage slightly, maybe enough to make a Pi unhappy. My Pi 3 with HAT and GR-701W is taking 350 mA. lsusb on the PC it's plugged into doesn't see any new USB devices so it didn't negotiate. If I fill up 1 CPU with NTP requests, it takes 430 mA. If I do a big memcpy, it takes 530 mA. memcpy and NTP take 560 mA. Without the 701W, it's only using 280 mA. That's when idle. -- These are my opinions. I hate spam. _______________________________________________ devel mailing list devel@ntpsec.org http://lists.ntpsec.org/mailman/listinfo/devel
