> -----Original Message-----
> From: Per Jessen <p...@jessen.ch>
> Sent: 04 December 2019 08:54
> To: opensuse-arm@opensuse.org
> Subject: RE: [opensuse-arm] any hints for getting ds1820s to work with my nano
> pi neo air?
>
> Guillaume Gardet wrote:
>
> >> For module 'w1-therm', I ended up adding 'strong_pullup=2' which
> >> reduced the number of bad readings, a lot.
> >
> > 1-wire should have CRC checksum to avoid wrong read.
>
> Yes, it does and the kernel module also checks and prints out a YES or a NO.
> Sometimes you still get a good reading (the CRC is good), but it reads 85000
> which
> is the DS18x20 saying "poor communication".
>
> Yesterday since 1500, I have read 3 sensors once a minute, that is approx.
> 3000
> readings. Of those, 73 had a bad crc, and 203 were bad readings (85000).
> That's
> actually pretty good, only 9% failure rate. I can possibly improve it with
> better
> cabling/routing.
The pull-up resistor value is very important. You can try a higher or a lower
value and test.
Guillaume
>
>
> --
> Per Jessen, Zürich (0.1°C)
> member, openSUSE Heroes
>
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