OneWire master and slave

rowan.bradley
Posts: 6
Joined: Tue Jan 01, 2019 3:31 pm

OneWire master and slave

Postby rowan.bradley » Tue Oct 27, 2020 12:58 pm

Has anyone implemented the Dallas/Maxim OneWire (1-Wire) protocol on an ESP? I need to build a OneWire hub (to enable me to connect multiple OneWire buses to a single OneWire master such as the DS9490R). This no longer seems easy since Maxim stopped making the DS2409. The best way forward in the absence of these chips seems to be to emulate the protocol using a micro like the ESP32. I'm looking to make an 8-way hub. I have no idea whether a single ESP32 could emulate 8 OneWire buses at once, or whether I would need more than one processor. I suppose the strong pullup function could be emulated by using two GPIOs for each OneWire bus, one for data in/out and one to turn on and off the strong pullup.

If anyone has any code, or design, or ideas to help me on this route, your input would be most appreciated.

Thanks - Rowan

WiFive
Posts: 2991
Joined: Tue Dec 01, 2015 7:35 am

Re: OneWire master and slave

Postby WiFive » Fri Oct 30, 2020 10:46 pm

You can find master implementations on github I don't know about slave

greg-dickson
Posts: 1
Joined: Sun Nov 01, 2020 1:51 am

Re: OneWire master and slave

Postby greg-dickson » Sun Nov 01, 2020 2:03 am

did you check
https://github.com/orgua/OneWireHub

It is fairly easy to implement in arduino and you can implement any known slaves and even your own if you can deal with it in the master

However on the esp32 I haven't tried it yet.

Also the one wire bus is often 5v but can be run at 3.3 it just depends on what slaves you are attaching to it and what are their requirements.
to run 5v parasitic slaves you would need a level translator that's all.

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