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DS28E17. Support

288 Views - Created 28 days ago

28 days ago

Posted by:
Lpeart

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Hi has anyone successfully connect a 1wire device that uses the DS28E17 to the 1 wire pi ?

28 days ago

Posted by:
andrew

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Location:
United Kingdom

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Hi

We have not tested the DS28E17 on the 1 Wire Pi.  In theory it should be compatible with the DS2482-100 1-Wire controller used on the 1 Wire Pi but the problem you will have is finding software drivers to communicate between the DS2482-100 and the DS28E17.

The DS28E17 is not listed as a compatible device on the OWFS website so you will not be able to use OWFS to talk to the device.  You may have to write a custom linux kernel driver to make the DS28E17 appear as an I2C bus within linux.  I don't have any experience with writing kernel drivers so this is not something I could help you with.

AB Electronics UK Tech Support

27 days ago

Posted by:
Lpeart

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The DS28E17 is supported by the kernel although that's for the gpio 1wire do you know if the existing kernel drivers can use this hardware instead of gpio ?

27 days ago

Posted by:
andrew

Last edited: 21/04/2021

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If you enable the DS2482 kernel module to work with the "w1" subsystem using the steps below you should be able to use the w1_ds28e17 kernel driver.

sudo modprobe ds2482
sudo sh -c "echo ds2482 0x18 > /sys/bus/i2c/devices/i2c-1/new_device"
sudo modprobe wire

Any one wire devices connected to the 1 Wire Pi will be available in the /sys/bus/w1/devices directory.

The github repository for the w1_ds28e17 driver has more information on getting it working.  It does say that the w1_ds28e17 driver is compatible with the DS2482 so it should work with the 1 Wire Pi but as I have not tested it myself I can not give you any guarantees that it will be compatible.

One issue you will find is the DS28E17 only works at 3.3V and the 1 Wire Pi is designed to work at 5V.  You can change the 1 Wire Pi to work at 3.3V by removing the jumper J1 on the 1 Wire Pi Plus or the POWER solder bridge on 1 Wire Pi Zero to isolate it from the 5V supply and connect a wire between the 3.3V pin on the Raspberry Pi GPIO header and the 5V pin next to the RJ12 connector on the 1 Wire Pi.  The photo below shows where the wire needs to connect.  This should convert the 1 Wire bus to be 3.3V making it compatible with the DS28E17. 

Be careful not to accidentally short the jumper pins once you have connected the 3.3V to the 1 Wire Pi as this will feed 5 volts directly into the 3.3V pin on the GPIO header and damage the Raspberry Pi.

Post image

If you need to use other 5V 1 Wire devices on the same bus as the DS28E17 there is a circuit in section "2.3  Interfacing the DS28E17 with a 5V onewire bus and/or 5V I2C device" of the w1_ds28e17 github repository which will level shift the 5V bus to 3.3V.

AB Electronics UK Tech Support

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