Has anyone used the OneWire protocol with the Seeeduino XIAO under MicroPython?

I am trying to use the OneWire protocol to talk to a DS18B20, but I don't think it is currently compiled in to MicroPython for SAMD21 based devices.

Am I correct? If so are there any recommended alternative libraries. If not then any thought as to what I am doing wrong?

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Alistair over 1 year ago in reply to scottiebabe +1

That is the command I was needed. Thanks. Yes, it confirms that onewire is not compiled in for some reason. It is documented as it should be, so perhaps I should try and nightly build and see what I get…

0 shabaz over 1 year ago

I've not used any of the boards/protocols you mention. However, MicroPython allows for general GPIO manipulation, and I believe 1-wire is slow enough that you could manually bit-bang your protocol if needed. That's what the author of this library has done:

https://github.com/robert-hh/Onewire_DS18X20

That library should work (or could be edited, since it is entirely in Python, manually bit-banging - no compiling needed).
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0 scottiebabe over 1 year ago

Can you post what you see when you type help('modules') into the REPL

(Pico example)
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0 Alistair over 1 year ago in reply to shabaz

Thanks for the the link. Following the same logic I found the same library, but sadly it is not detecting the sensor. I checked the wiring by connecting to an Arduino for a test and it worked, so I suspect it is an oddity around the XIAO and Micropython in some way. Perhaps it is timing as that feels critical and relying on quick execution looking at the code. I might connect it up to the scope to see what is actually happening at the hardware end and see it that gives me a clue. Thanks for the pointer though.
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0 Alistair over 1 year ago in reply to scottiebabe

That is the command I was needed. Thanks. Yes, it confirms that onewire is not compiled in for some reason. It is documented as it should be, so perhaps I should try and nightly build and see what I get.
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0 shabaz over 1 year ago in reply to Alistair

There are sleep_us() operations in the code, it's very likely they may need tweaking (checking with an oscilloscope), since the timings won't be too accurate in that way at the microsecond level with MicroPython.

I2C is a better protocol for on-board sensors (appreciate that doesn't help with the immediate problem, but for future use).
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