On 5 September 2016 at 20:13, Jan Kandziora <j...@gmx.de> wrote: > Am 05.09.2016 um 17:23 schrieb Colin Law: >> As in an earlier thread I am using an DS18B20 directly connected to >> GPIO pins of a Pi Zero with 1.5k pullup, operating at 3.3v. Owserver >> is version 3.1p1-6 from raspbian testing. >> >> I have specified >> dtoverlay=w1-gpio,gpiopin=4 >> and done >> sudo modprobe w1-gpio pullup=1 >> >> This basically works, both when connected in parasitic and 3 wire mode >> but about 1 in 20 reads I get a read error (in both modes). >> > That's something you have to take provisions for. OWFS doesn't retry > itself. I have spurious errors in my machines too (of course, a lot of > chips and cabling) with I²C and USB host adapters. > > With the bitbanging host, I think it's connected to CPU frequency > scaling and other powersave measures. You could try to disable all this > and check if it gets better. > > But I would just retry. YOu have to in any case for other errors.
My 'production' software does retry. On other parts of my system I have used adaptors such as the LinkUSB and get read errors only at a very low level, below 0.1% I think, so I had not expected it to be 100 times worse. However I can see that bit-banging is inherently going to be much less reliable so I will make sure my system can cope with that. Thanks Colin ------------------------------------------------------------------------------ _______________________________________________ Owfs-developers mailing list Owfs-developers@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/owfs-developers
