>
>
> >OWFS handles multiple adapters seemlessly. There is no specified limit on
> the number, but I haven't tried 10-15. You can also partition the master
> among multiple machines, or multiple instances of owserver on the same
> machine. The overhead is minimal.
>
>
>
> So the answer is - yes, OWFS has correct routing between lines? In my
> opinion, multiple adapters on host 1 can work absolutely different:
>
>
Routing is on several levels:
Operating System
--------------------------
USB devices to operating system bus/device number. -- This seems to be
arbitrary, or at least hard to control. (reconnects assign a different
address, other USB activity influence the result, etc.)
Modern DS9490R bus masters have a id chip (family code 81) which might be
used to uniquely identify them.
The contents of each 1-wire bus has a set of unique IDs.
I2C and serial masters have a consistent operating-system assigned address
that can be used.
OWFS bus.x
-------------------
OWFS assigns "bus.0, bus.1 ..." in order to each bus master it finds. This
depends on the command line sequence, and how libusb device enumeration is
given. So it can be inconsistent.
Once a particular USB device is assigned a bus.x number, we try to keep the
same assignment based on the family code 81 device.
So if you check the bus.x contents after startup, and select the mapping you
like, it should stay consistent for that run of OWFS.
OWFS devices
----------------------
Now routing of devices to bus activity.
When a device is requested (/10.12345AB0000/temperature for example), OWFS
looks at an internal table to see if the device is known and assigned to a
particular bus. If so, only that bus is queried and other activity on other
buses can take place simultaneously (multithreading). If the device isn't
known, all the buses are queried simultaneously for it's presence. The
internal table has a timeout of several minutes, but that can be tuned.
You can also ask that only a particular bus is queried by requesting, for
example /bus.2/10.12345AB0000/temperature, but that requires you keep an
external table of assignments.
>
>
> 1. Software use general BUS 0 (host 1) which is divided by BUS'es 0.1
> (usb0) and 0.2 (usb1)
>
> outputs from BUS 0 routed to BUS 0.1 0.2
>
> inputs from BUS 0.1 routeed to BUS 0
>
> inputs from BUS 0.2 routeed to BUS 0
>
>
>
> 2. BUS 0.1 and 0.2 are separete buses
>
> outputs from BUS 0.1 routed to BUS 0.1
>
> inputs from BUS 0.1 routed to BUS 0.1
>
>
>
> Has OWFS any "routing tables"? How this can be implemented when all usb
> connections are not permanent?
>
>
>
> >USB has an issue with enumeration -- the same adapter will be assigned a
> different slot. We try to search for the unique ID (family code 81) when
> "reconnecting" but it's a fundemental limitation of the operating system.
> Probably your code should search through all adapters for known slaves and
> make assignments dynamically.
>
>
>
> Before polling the devices i have to mount owfs line, but to make it
> correctly i need to know how are corresponding the usb ports and 1W lines
> among themselves. Probably is necessary to make mountpoint static:
>
>
>
> 1W-USB #1 -> /dev/usb#unknown -> /mnt/line#static1 -> line 1, set virtually
> by adapter's unique ID
>
>
>
> that seems to be really strange :/ Or you are talking about OWFS build-in
> feature?
>
>
>
> >Two adapters can be connected to the same 1-wire net as long as only 1 is
> active. Can you poll and switch over? Again, I haven't actually tried this.
>
>
>
> I guess simple parallel connection should work well with software "switch".
> Only one adapter per line is active. There is a modern solution for adding
> gpio's, ADC and other devices to PC or embedded device. Most of chips can be
> connected by i2c which is supported by kernel. 1W PSU can be based on
> PCA9535, ADS7828, DAC5571 or similar and connected with usb-i2c adapter to
> server, such adapters are rather widespread and cheap. This gives me
> powerful control of 1W lines. OWFS is good for long distances (10-100m)
> where i can check integrity of 1W line by label at end and use optocoupler.
> Device will stay in last mode until the power is off. But remote controlled
> switch on 1W data line is unsecure. If there is no possible software trouble
> with 2 adapters in parallel i will use it. But i dont want to use 1W for PSU
> control as well as 1W that depends on PSU. Therefore i think to make PSU
> that is fully managed by kernel and partially by 1W.
>
>
I think that most of the masters will ignore activity on the line if they
aren't in the middle of communication, besides an occasional spurious
presence pulse, which we ignore in owfs. So an inactive 2nd master will not
interfere (again, untested) as long as the default master mode isn't
shorting the line (which I doubt). When the first master is taken down and
the second activated, the bus will be in an undefined state, and all the
devices will need to be initialized. In general that isn't an issue with
1-wire devices, except perhaps for some of your PIO controls.
>
>
> What about correct wiring? Cat5 has 4 pairs, but most of hobby-board and
> our Elin's company use only 2 of them.
> http://www.elin.ru/1-Wire/Support/(sorry for russian, but there is lot of
> pdf's with schemes). May be OWFS
> support more clever wiring than just one long bus with one adapter? Loop, 2
> adapters for 1 bus (by one at both ends) and so on. With 2 adapters i can do
> software splitting of 1 bus when data bus fails.
>
My impression is that the wiring is transparent to owfs. We really don't see
anything on the other side of the Bus Master, except throug the master. If
you can conceive of out-of-band control, I'd be happy to consider adding it.
>
>
> Thank you for great software! No failover for 4 years non-stop on small
> HVAC: http://crymos.ru/uploads/images/engineering/statistic.txt (current
> statistic) Was working for 1 month even with dead HDD!
>
Great to hear!
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