DS2409(3)

NAME
DS2409 - MicroLAN Coupler

SYNOPSIS
1-wire network branch controller.

1F [.]XXXXXXXXXXXX[XX][/[ aux | branch.[0|1|ALL|BYTE] | control | discharge | event.[0|1|ALL|BYTE] | clearevent | main | sensed.[0|1|ALL|BYTE] | ]]

FAMILY CODE

1F

SPECIAL PROPERTIES

  aux
directory
This is the aux branch of the DS2409 network branch. It is implicitly accessed (via the aux smart-on command) when it is listed or devices on this branch are addressed.

  branch.0 branch.1 branch.ALL branch.BYTE
read-write, yes-no
Writing a value of 1 to the branch properties explicitly selects the meant branch ( 0=main or 1=aux ). Writing 0 deselects the branch. This is an addition to the directory branch selection scheme available by simply accessing the main and aux directories. Both ways to select a branch coexist nicely but the latest scheme used wins. Attempting to select both branches, either by setting both bits at the same time or subsequently, fails. Clearing both branch selection bits, either by clearing both bits at the same time or subsequently, resets the event flags inside the DS2409 as a side effect. Reading the branch properties returns which branch (if any) is connected to the master bus.

After using the directory branch selection scheme, both branches are deselected automatically.

ALL is an aggregate of the properties, comma separated. It is an atomic operation.
BYTE is an aggregate of the branches as a byte, main is bit 0. It is an atomic operation.

  control
read-write, unsigned integer
Setting of the PIO control pin. There are 4 possible settings:

0   Unconditionally off (non-conducting)

1   Unconditionally on (conducting)

2   Auto on when main branch switched in

3   Auto on when aux branch switched in

  discharge
write-only, yes-no
Writing a non-zero value to this property will electrically reset both the main and auxiliary branches of the 1-wire bus by dropping power for 100 milliseconds. All devices on those branches will lose parasitic power and reset to power-up defaults. As a side effect, both event flags and thus, the alarm state, are cleared, too.

  event.0 event.1 event.ALL event.BYTE
read-only, yes-no
Has the event flag for the branch been triggered? A negative edge on the disconnected branch ( 0=main or 1=aux ) sets the flag. This is achieved by e.g. connecting an iButton to the branch. Value returned is 1 (yes) or 0 (no).

After accessing the main or aux directory, both branches are deselected automatically and thus, the event flags and alarm state are cleared.

ALL is an aggregate of the properties, comma separated. It is an atomic operation.
BYTE is an aggregate of the branches as a byte, main is bit 0. It is an atomic operation.

  clearevent
write-only, yes-no
Writing a non-zero value to this property will reset both event flags and thus, clear the alarm state, too.

  main
directory
This is the main branch of the DS2409 network branch. It is implicitly accessed (via the main smart-on command) when it is listed or devices on this branch are addressed.

  sensed.0 sensed.1 sensed.ALL sensed.BYTE
read-only, yes-no
Voltage sensed at the 0=main or 1=aux branch pin. Valid only when the branch is switched out. Value returned is 0 (low) or 1 (high).

ALL is an aggregate of the properties, comma separated. It is an atomic operation.
BYTE is an aggregate of the branches as a byte, main is bit 0. It is an atomic operation.

STANDARD PROPERTIES

ALARMS
The DS2409 will respond to a conditional search if the main event flag is set.

DESCRIPTION

  DS2409
The DS2409 (3) allows complex 1-wire network topology. Each branch has it's power preserved, even when isolated from the master. A separate PIO pin can be configured to show branch switching, or controlled explicitly.

ADDRESSING

DATASHEET
http://pdfserv.maxim-ic.com/en/ds/DS2409.pdf

SEE ALSO

AVAILABILITY
http://www.owfs.org

AUTHOR
Paul Alfille (paul.alfille@gmail.com)