On 3 September 2016 at 13:04, Jan Kandziora <j...@gmx.de> wrote: > Am 03.09.2016 um 10:36 schrieb Colin Law: >> I want to use owserver on a raspberry pi (zero) running Raspbian >> (Jessie) using the method of direct connection to GPIO pins with a >> pullup resistor. Unfortunately I have found a fair amount of >> conflicting and confusing information on this around the web. Is >> there an up to date and authoritative write up somewhere on how to do >> this? >> > 1. You have to recall the Raspberry Pi's GPIOs are 3.3V. You'll have a > non-standard 3.3V Onewire then. That's okay for the DS18B20, but for > other Onewire chips, you have to check the datasheets. Same, if you > use an external pullup, it has to go to 3.3V, not 5V. > > Of course, you can always use this simple level shifting circuit, should > you need a 5V Onewire: > > | > | +5V ----. ,-----+---- +3.3V > | | | | > | \ G | \ > | / –––––' / > | \ ––– – ––– \ > | | | ^ | | > | 5V bus line ---+-----' '--+-----+---- 3.3V bus line > | D S > | > > The transistor is a small signal N-channel enhancement mode MOSFET, e.g. a > 2N7000, BS170 or MMBF170. The value of the two pullup resistors depend on > the pullup current you need, 1.5kΩ is okay for most cases. > > > 2. You have to put > > dtoverlay=w1-gpio,gpiopin=4 > > or > > dtoverlay=w1-gpio-pullup,gpiopin=4,pullup=5 > > into your Raspberry Pi boot partition config.txt. And of course, the > w1-gpio resp. w1-gpio-pullup dtb files have to be present in the boot > partition overlays directory. Then reboot. > > > 3. You have to use --w1 for this. The w1 kernel driver is the only way > to use the bitbanging host adapter. > > > 4. You have to update your owfs to 3.1p1 or later, because Debian Jessie > uses kernel 3.16.x, and there was a long-unseen incompatiblity between > post-3.16rc kernels and pre-3.1p1 owfs. > > You can use the owfs packages from the Raspbian testing repository. Edit > (or create) your /etc/apt/preferences to contain: > -------------------------------------------------------------------------- > Package: * > Pin: release o=Raspbian,a=stable > Pin-Priority: 500 > > Package: * > Pin: release o=Raspbian,a=testing > Pin-Priority: 300 > -------------------------------------------------------------------------- > This is important so you keep stable (Jessie) for all packages but the ones > explicitly taken from testing (Stretch). > > > Then, add a line > -------------------------------------------------------------------------- > deb http://mirrordirector.raspbian.org/raspbian/ testing main contrib > non-free rpi > -------------------------------------------------------------------------- > to your /etc/apt/sources.list to get access to the Raspbian testing > repository. > > Do an > > $ sudo apt-get update > > to read the package metadata, then check > > $ sudo apt-cache policy > > whether the testing repo is there with priority 300. Then > > $ sudo apt-get update -t testing owserver ow-shell > > That should install all you need, including the startup files and systemd > units. > Note you have to edit /etc/owfs.conf again to contain (this and only this) > -------------------------------------------------------------------------- > !server: server = localhost:4304 > server: w1 > -------------------------------------------------------------------------- > Restart the owserver service after that. > > > Done.
That's great Jan Many thanks Colin ------------------------------------------------------------------------------ _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
