DS2409 Dallas Semiconducotr, DS2409 Datasheet - Page 14

• Manufacturer Part Number: DS2409
• Description: MicroLAN Coupler
• Manufacturer: Dallas Semiconducotr

USAGE EXAMPLE
Configuration: A bus master controls a MicroLAN consisting of a trunk with many DS2409s that create
branches. Each of the DS2409s has a DS2430A connected to its auxiliary output to label its physical
location in the network (see Figure 10). iButton devices are constantly arriving at or departing from the
branches.
Task: Identify one branch where an iButton has arrived and get the branch’ s physical location. Determine
the population on that particular branch.
* 00h or 01h if presence pulse, FFh if no presence pulse
Note: The sequence of steps 12 to 21 logically decouples all other devices residing on the trunk from
responding to the search ROM command. The All Lines Off command is required to clear the event flag
that made the device respond to the conditional search command.
STEP
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
1
2
3
4
5
6
7
8
9
repeat steps 12 to 21 for each of the remaining devices on the branch of the identified coupler
MASTER MODE
RX/RX/TX
RX/RX/TX
RX
RX
RX
RX
RX
RX
RX
RX
RX
RX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
TX
for each of the 64 ROM bits
for each of the 64 ROM bits
DATA (LSB FIRST)
<8 byte ROM ID>
<8 byte ROM ID>
<32 data bytes>
<data byte>*
<data byte>*
Presence
Presence
Presence
Presence
Reset
Reset
Reset
Reset
ECh
CCh
CCh
CCh
FFh
FFh
33h
33h
F0h
55h
F0h
55h
66h
66h
14 of 18
Reset pulse (480–960 µs)
Presence pulse
Issue “conditional search ROM” command
Identify and access one of the qualifying devices
Issue Smart-On Auxiliary command
Send reset stimulus
Get reset response byte with presence info
Get confirmation byte
Issue “skip ROM” command
Issue “read memory” command
Get branch location information (DS2430A)
Reset pulse
Presence pulse
Issue “Match ROM” command
Access the previously identified coupler
Issue Smart-On Main command
Send reset stimulus
Get reset response byte with presence info
Get confirmation byte
Issue “search ROM” command
Identify one of the devices connected
Reset pulse
Presence pulse
Issue “Match ROM” command
Access the previously identified coupler
Send all lines off command
Get confirmation byte
Reset pulse
Presence pulse
COMMENTS
102199
DS2409