Introduction¶

… or “how to talk to 1wire in five minutes”[1].

[1]	Setting up an owserver <http://owfs.org/uploads/owserver.html> instance not included.

First, create an OWFS instance:

import trio
from trio_owfs import OWFS

async def main():
    async with OWFS() as ow:
        await setup_onewire(ow)
        pass # do whatever you want with 1wire

trio.run(main)

Optionally, start an event monitor:

async def setup_onewire(ow):
    await ow.add_task(monitor, ow)

async def monitor(ow):
    with ow.events as events:
        async for msg in events:
            logger.info("%s", msg)

Connect to one or more owserver instances:

async def setup_onewire(ow):
    # … continued
    s = await ow.add_server("127.0.0.1")

At this point, the server is connected and its bus has been enumerated. The connection to the server is kept alive and will automatically be re-established until you leave the with OWFS() block, or call await s.aclose().

Your event monitor receives a trio_owfs.event.DeviceLocated event for each 1wire slave; in a more complicated program, it should match them with your configuration file.

You can also ask by device ID, and get/set attributes if the device is present:

dev = await ow.get_device("10.DBDB39010800.EF")
# triggers a :class:`trio_owfs.event.DeviceAdded` event if not yet known
if dev.bus is not None:
    # make sure that the data accessor methods are loaded
    await ow.ensure_struct(dev)

    heat = await dev.temperature
    await dev.set_temphigh(99)

Note that all IDs are in FDIDC for (family, dot, ID, dot, checksum).

You can arrange for periodic bus scans, or trigger them yourself:

await ow.scan_now()

Re-scanning will automatically add new buses and devices, relocate moved devices, free buses which have been disconnected, and de-locate (i.e. remove the bus attribute from) devices that can no longer be found.

Trio-OWFS transparently supports the DS2509 <http://owfs.org/uploads/DS2409.html> bus coupler, by creating (and auto-scanning) two buses for its main and aux ports. Don’t change its settings yourself; you’re likely to confuse your owserver.