RE: [opensuse-arm] any hints for getting ds1820s to work with my nano pi neo air?

-----Original Message----- From: Per Jessen 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:

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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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