OWFS Design
OWFS Features
OWFS Software
Examples & Usage
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| OWFS Array Files
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Some
of the 1-wire device properties are best described as arrays. OWFS
presents the 1-wire data as a set of files with consistent naming and
attributes. Additionally, if the chip supports it, you can change the
properties simultaneously (atomically).
Naming
Files are named name.index
where name is the property
and index gives the
individual element. Index is usually of the form 0,1, ... although a
few indicies are of the form A,B,... .
Letters are used only
ALL
Each set of array files also has a file name.ALL which represents all the
files put together. the .ALL file has the same format as the
individual array files, possibly separated by commas (unless the
contents are binary). Changes are made simultaneously if possible (See
Atomic below).
Atomic
If the underlying 1-wire chip supports it, the .ALL file represents all
the values at the same time, and any changes are made simultaneously
(atomically). This can be useful for changing switches. Usually these
atomic operations are individual bits in a register. Array files for an
atomic property are extracted from the .ALL file.
Aggregate
For properties that are not atomic, aggregation is used instead. the
.ALL file is created from each of the individual array files called in
turn. In contrast, atomic .ALL is read directly from the chip and the
individual files are extracted from it.
The main implications of the atomic/aggregate distinction is threefold.
First, atomic changes are made simultaneously. Second it is much
more efficient to change atomic .ALL files if multiple values need to
be changed.Aggregate .ALL changes are essentially made by individual
calls for each element, so changing several elements should be done
indivudually. Finally, if caching is implemented, atomic properties
cache .ALL while aggregate properties cache individual element files.
Separators
The .ALL contains the individual array elements separated by a comma.
Pure memory (binary) data is not comma separated.
Examples:
DS1993 4kb Memory iButton
Memory is organized as 16 pages of 32 bytes each.
# ls -al 06.8FD62D000000/*.*
Note that each page has the format page.* with length 32 bytes.
Also, file page.ALL is the combined page.?? files with length 16*32=512
bytes.
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-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.0
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.1
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.10
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.11
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.12
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.13
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.14
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.15
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.2
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.3
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.4
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.5
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.6
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.7
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.8
-rw-rw-rw- 1 root root 32 Oct 11 08:26 06.8FD62D000000/page.9
-rw-rw-rw- 1 root root 512 Oct 11 08:26 06.8FD62D000000/page.ALL
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DS 1982U UniqueWare iButton
Similar, 4 pages of 32 bytes.
# ls -al 89.BD29C300705E/*.*
# for x in 89.*/*.* ; do echo $x; od -Ax -w32 -x $x; done
Since page format is binary, page.ALL has no comma separating the
individual pages.
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-rw-rw-rw- 1 root root 32 Oct 11 11:31 89.BD29C300705E/page.0
-rw-rw-rw- 1 root root 32 Oct 11 11:31 89.BD29C300705E/page.1
-rw-rw-rw- 1 root root 32 Oct 11 11:31 89.BD29C300705E/page.2
-rw-rw-rw- 1 root root 32 Oct 11 11:31 89.BD29C300705E/page.3
-rw-rw-rw- 1 root root 128 Oct 11 11:31 89.BD29C300705E/page.ALL
89.BD29C300705E/page.0
000000 280c 0011 2800 00b8 0000 6035 dd00 ffd4 ffff ffff ffff ffff ffff ffff ffff ffff
000020
89.BD29C300705E/page.1
000000 ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff
000020
89.BD29C300705E/page.2
000000 ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff
000020
89.BD29C300705E/page.3
000000 ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff
000020
89.BD29C300705E/page.ALL
000000 280c 0011 2800 00b8 0000 6035 dd00 ffd4 ffff ffff ffff ffff ffff ffff ffff ffff
000020 ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff ffff
*
000080
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LCD contoller (Louis
Swart version)
Several properties are array values.
Changing the screen, for example, can be done by:echo "OWFSsystem,line
two,
# ls *.*
# echo "OWFS system,line two," > FF.3D0100000100/line16.ALL
Note that the second comma is needed if all 4 elements are supplied.
Integer values can also be in an array:
# cat FF.3D0100000100/counters.ALL
# cat FF.3D0100000100/counters.ALL
Note that the second time through, the counters have been read, and
thus cleared. Use the cumulative property to see the total counts.
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counters.0 gpio.0 line16.0 line20.0 line40.0
counters.1 gpio.1 line16.1 line20.1 line40.1
counters.2 gpio.2 line16.2 line20.2 line40.ALL
counters.3 gpio.3 line16.3 line20.3
counters.ALL gpio.ALL line16.ALL line20.ALL
0, 2, 4, 0
0, 0, 0, 0
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