[Owfs-developers] How to perform lowlevel read operation from libow or libcapi?

[Потапенко Сергей]

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[Jan Kandziora]

Hi,
Please help me with libow (owfs) API.
How I can send the command "Read ROM" (0x33) and get response from OW bus at
this? This is needed for working with ds1990 similar device .
How I can get access to lowlevel iface of OW bus from private data structures
of libcapi ?

Reading the /bus.0/simultaneous/single node issues a READ ROM (0x33)
command. Reading the /bus.0/simultaneous/single_ds2400 node issues a
READ ROM (0x0F) command. The result in both cases is the ID of the
single chip connected to the selected bus (here: bus.0).

e.g.

# owserver --i2c=ALL:ALL


$ owread /bus.0/simultaneous/single

Please note you cannot use these nodes with the DS9490 host adapter, as
it already has an iButton built-in. Connecting another onewwire chip and
issuing any of these commands results in wired-and garbage data.

Kind regards

Jan

[Jan Kandziora]

How I can get access to lowlevel iface of OW bus from private data structures
of libcapi ?

You cannot. Libow and owcapi are just there to hide those details from
the user.

If you want to access a new slave chip, the easiest way is to add
support for it in owfs. Find the existing code under
modules/owlib/src/c/. If you provide information and are willing to
test, we could also help you adding support for your ow slave chip.

Kind regards

Jan