DS2409P+ ,MicroLAN CouplerPIN DESCRIPTIONcontrol outputPin 1 GND Communicates at 16.3kbits per secondPin 2 1-Wire in Unique ..
DS2411 ,Silicon Serial Number with VFEATURES PIN CONFIGURATION Unique, Factory-Lasered and Tested 64-Bit 3 Registration Number (8-B ..
DS2411 ,Silicon Serial Number with VPIN DESCRIPTION *The DS2411X is RoHS qualified and comes in tape and reel. PIN NAME FLIP SOT23 ..
DS2411P ,Silicon Serial Number with VCC InputPIN DESCRIPTIONPART TEMP RANGE PACKAGEPINDS2411R/ SOT23-3,NAME FLIP-40C to +85CSOT23 TSOCT&R Tape ..
DS2411P+ ,Silicon Serial Number with VCC InputFEATURES PIN CONFIGURATION Unique, Factory-Lasered and Tested 64-Bit 3 Registration Number (8-B ..
DS2411R+T&R ,Silicon Serial Number with VCC InputPIN DESCRIPTION *The DS2411X is RoHS qualified and comes in tape and reel. PIN NAME FLIP SOT23 ..
E53NA50 ,NABSOLUTE MAXIMUM RATINGSSymbol Parameter Value UnitV Drain-source Voltage (V =0) 500 VDS GSV 500 VD ..
DS2409P+
MicroLAN Coupler
FEATURESLow impedance coupler to create large
common-ground, multi-level MicroLAN
networksKeeps inactive branches pulled high to 5VSimplifies network topology analysis by
logically decoupling devices on active
network segmentsConditional search for fast-event signalingAuxiliary 1-Wire® line to connect a memory
chip or to be used as digital inputProgrammable, general-purpose open-drain
control outputCommunicates at 16.3kbits per secondUnique, factory-lasered and tested 64-bit
registration number (8-bit family code + 48-
bit serial number + 8-bit CRC tester) assures
absolute traceability because no two parts are
alike8-bit family code specifies device
communication requirements to bus masterBuilt-in multidrop controller ensures
compatibility with other MicroLAN productsOperating temperature range from -40°C to
+85°CCompact, low-cost 6-pin TSOC surface
mount package
PIN ASSIGNMENT
PIN DESCRIPTIONPin 1GND
Pin 21-Wire in
Pin 3Main 1-Wire out
Pin 4Auxiliary 1-Wire out
Pin 5Control Output
Pin 6VDD
ORDERING INFORMATIONDS2409P6-pin TSOC package
DS2409P/T&RTape and Reel of DS2409P
DESCRIPTIONThe MicroLAN coupler is an essential component to build and control 1-Wire MicroLAN networks with
multi-level branching. In contrast to approaches that switch the ground line, the coupler maintains a
common ground level for the whole network and keeps the inactive segments powered. This simplifies
supplying central or local power for additional circuitry and prevents loss of status of parasitically
powered devices. It also avoids disrupting communication caused by the parasitic power supply of 1-Wire
devices after activating a branch. The coupler does not contain any user-programmable memory. To label
a branch, one can connect any 1-Wire memory device to the auxiliary 1-Wire output of the coupler. Both
the main and the auxiliary 1-Wire output are supported by a “smart-on” command. This command
generates a reset/presence sequence on the selected output before the electronic switch closes the contact
DS2409
MicroLAN Coupler
TOP VIEW
3.7mm X 4.0mm X 1.5 mm
SIDEVIEW
6-PIN TSOC PACKAGE
Not Recommended for New Design
DS2409
remaining deselected. This significantly speeds up the analysis of topology and population in a
continuously changing network. The coupler also supports the bus master in detecting arrivals on the
inactive segments of the network by responding to the conditional search command. The control output
can be used to optically signal the on/off state of a branch or, together with the auxiliary output, for
handshaking in dual-master applications. The network size can be maximized by using a DS2480 line
driver at the bus master’s serial interface. The DS2480 compensates for the rising ground level caused by
the non-zero on-resistance of couplers in multi-level networks.
OVERVIEWThe DS2409 Coupler provides a means to create large MicroLAN networks with additional control
capability provided by an open-drain N-channel MOSFET that can be remotely switched via
communication over the 1-Wire bus (Figure 1). An auxiliary output can be used to label the branch by
connecting a programmed 1-Wire memory chip or as digital input. The DS2409 contains a factory-lasered
registration number that includes a unique 48-bit serial number, an 8-bit CRC, and an 8-bit family code
(1FH). The 64-bit ROM portion of the DS2409 not only creates an absolutely unique electronic
identification for the device itself but also is a means to locate and address the device in order to exercise
its control functions.
The DS2409 uses the standard Dallas Semiconductor 1-Wire protocol for data transfers (Figure 2), with
all data being read and written least significant bit first. Communication to and from the DS2409 requires
a single bi-directional line that is typically a port pin of a microcontroller. The 1-Wire bus master
(microcontroller) must first issue one of five ROM function commands: 1)Read ROM, 2) Match ROM,
3) Search ROM, 4) Skip ROM, or 5) Conditional Search ROM. These commands operate on the 64-bit
lasered ROM portion of each device and can singulate a specific device if many are present on the 1-Wire
line as well as indicate to the bus how many and what type of each device is present. After a ROM
function command is successfully executed, the control functions of the device can be exercised via the 1-
Wire bus.
BLOCK DIAGRAM Figure 1
Not Recommended for New Design
DS2409
64-BIT LASERED ROMEach DS2409 contains a unique ROM code that is 64 bits long. The first eight bits are a 1-Wire family
code. The next 48 bits are a unique serial number. The last eight bits are a CRC of the first 56 bits. (See
Figure 3.) The 1-Wire CRC of the lasered ROM is generated using the polynomial X8 + X5 + X4 + 1.
Additional information about the Dallas Semiconductor 1-Wire Cyclic Redundancy Check is available in
the Book of DS19xx iButton® Standards. The 64-bit ROM and ROM Function Control section allow the
DS2409 to operate as a 1-Wire device and follow the 1-Wire protocol detailed in the section “1-Wire Bus
System”. The functions required to exercise the control functions of the DS2409 are not accessible until
the ROM function protocol has been satisfied. This protocol is described in the ROM functions flow
chart (Figure 7). The 1-Wire bus master must first provide one of the five ROM function commands.
After a ROM function sequence has been successfully executed, the bus master may then provide any one
of the function commands specific to the DS2409 (Figure 5).
HIERARCHICAL STRUCTURE FOR 1-WIRE PROTOCOL Figure 2
64-BIT LASERED ROM Figure 3MSBLSB
8-Bit CRC Code48-Bit Serial Number8-Bit Family Code (1FH)
MSBLSBMSBLSBMSBLSB
Not Recommended for New Design
DS2409
1-WIRE CRC GENERATOR Figure 4
CONTROL FUNCTION COMMANDSThe “Control Function Flow Chart” (Figure 5) describes the protocols necessary for controlling the main
and auxiliary output as well as the control output of the DS2409. The 1-Wire Function Control section
and the Coupler Function Control section combine to interpret the commands issued by the bus master
and create the correct control signals within the device. Depending on the complexity of function to be
exercised, the 1-byte command code may require one or two more bytes being sent by the bus master.
Switching one branch on implies that the other branch is automatically switched off. At power-on, both
branches are switched off. Each command flow includes at least one byte of feedback information for the
bus master to check if the command was understood and executed.
STATUS READ/WRITE [5Ah]This command should be sent to the device after powering up unless the default settings are adequate for
the application. Following the command code, the bus master has to send the status control byte. The bus
master will then read the status info byte from the device. The confirmation byte is identical to the status
info byte. Tables 1 and 2 show the bit assignments in both bytes.
At power-on the device will be in the auto-control mode and the control output will be assigned to the
main output. The control output can be assigned to the auxiliary output by setting bit 6 of the status
control byte to a 1. For manual operation of the control output one has to select manual mode (bit 5 = 1).
The value of bit 7 of the status control byte will then determine the status of the control output. A 1 for bit
7 will make the transistor conducting, a 0 will turn it off (non-conducting). To change the status of the
device, both bits 3 and 4 of the status control byte have to be 0. Otherwise the settings will remain
unchanged. In any case, the status info byte will reflect the currently valid settings including the changes
that might have been made with the status control byte.
The status info byte allows the bus master to verify the actual status of each output (STAT,
active/inactive, on/off) and the static level at the main and auxiliary output (LEVL, 1 for normal, 0 in case
of a short). If a 1-Wire output is inactive and a low-going edge is encountered during this time, the
DS2409 will set the event flag (EVNT) the status info byte. Each output has its own event flag. The event
flags are cleared with the All Lines Off command. Bit 7 of the status info byte tells if the device is auto-
control mode or manual mode. Depending on the value of this bit, the information in bit 6 (CNTR.
STAT) either reports the association of the control output to a particular output (auto-control mode) or the
status of the transistor at the control output.
Not Recommended for New Design
DS2409
STATUS CONTROL BYTE Table 1
76543210DATA
CNTR.
SEL.MODER/WR/WXXX
0-2Xdon’t care
3-4R/WWrite control: both bits must be 0 to change the status.
MODEcontrol output mode selection: 0 = auto-control mode (default), 1 = manual mode
CNTR.
SEL.control output association (auto-control mode): 0 = main (default), 1 = auxiliary
DATAValue to be written to control output (manual mode only): don’t care otherwise
STATUS INFO BYTE Table 2
76543210MODECNTR.
STAT
EVNT
AUX.
EVNT
MAIN
AUX.
LEVL
AUX.
STAT
MAIN
LEVL
MAIN
STAT
MAIN
STATstatus of main output: 0 = active (connected to bus master), 1 = inactive
MAIN
LEVLvoltage sensed at main output: 0 = low, 1 = high (see note)
AUX.
STATstatus of auxiliary output: 0 = active (connected to bus master), 1 = inactive
AUX.
LEVLvoltage sensed at auxiliary output: 0 = low, 1 = high (see note)
EVNT
MAINevent flag for main output: 0 = no event, 1 = negative edge sensed since inactive
EVNT
AUX.event flag for aux. Output: 0 = no event, 1 = negative edge sensed since inactive
CNTR.
STAT
if auto-control mode: control output association, 0 = main, 1 = auxiliary
if manual mode: 0 = output transistor off, 1 = output transistor on
MODEcontrol output mode: 0 = auto-control mode, 1 = manual mode
NOTE:Data is valid only if the output is decoupled from the 1-Wire input.
ALL LINES OFF [66h]This command is used to deactivate the currently active 1-Wire output and to clear both event flags or to
end a discharge cycle initiated by the Discharge Lines command. Before issuing this command, one
should read the status and check the event flags of both, the main and the auxiliary output. Otherwise one
might inadvertently clear the event flag without having taken appropriate action. If the DS2409 is in auto-
control mode, the transistor at the control output will be switched off (non-conducting). At power-on, the
device will automatically perform the All Lines Off command. In contrast to a power-on cycle, the All
Lines Off command does not clear the Mode and Control Select bits.
Not Recommended for New Design
DS2409
DISCHARGE LINES [99h]
There may be situations where one has to force a power-on reset for parasitically powered 1-Wire devices
connected to the main or auxiliary output of the DS2409. For this purpose, the Discharge Lines
command has been implemented. This command first deactivates the output lines and then turns on the
pulldown transistors of both, the main and the auxiliary outputs. This state will be maintained until the
bus master accesses the coupler again and issues a different control function command. The duration of
the discharge time should be 100ms minimum and is controlled solely by the bus master.
Although any of the other control function commands will end the discharge cycle, it is recommended to
use the All Lines Off or Status Read/Write command to do so. This will allow the discharged lines to
fully recharge and prevent a sudden voltage droop on the active part of the network in case of a Direct-On
Main command. This precaution is not necessary with the Smart-On command.
DIRECT-ON MAIN [A5h]
The Direct-On Main command is typically used to activate the main 1-Wire output to subsequently issue
a reset pulse and access a device residing on the segment of the MicroLAN connected to the Main output
of the DS2409. If this command is received, the DS2409 will automatically set the auxiliary output to
inactive. Depending on the currently valid device status settings, the transistor at the control output may
change state (see Status Read/Write command).
SMART-ON MAIN [CCh]
When analyzing huge MicroLAN networks for changes in population it may be useful to limit the number
of devices participating in a Search ROM command. The smaller the number of participants, the faster
the responding devices are identified. The DS2409 supports the bus master in this process with the Smart-
On Main command. As a preparation for the subsequent steps, the first action of the Smart-On Main
command is deactivating the main output.
Compared to the Direct-On Main command, the Smart-On Main requires the bus master to follow the
function command with 16 more time slots. The first 8 time slots (reset stimulus) are translated by the
DS2409 as a reset low time on the Main 1-Wire output. Now, the bus master reads the reset response
byte. This generates the reset high time where devices connected to the Main 1-Wire output may assert
their presence pulse. If a presence pulse was found, several of the most significant bits of the reset
response byte will be zeros. After these 16 time slots are completed the Main 1-Wire output will be
activated (= through-connected to the 1-Wire input of the DS2409). Now, only the devices on the newly
activated segment of the MicroLAN are ready to receive a ROM function command optionally followed
by a memory function command. All other devices in the network will remain silent until the next reset
pulse is issued.
As with the Direct-On command, the Smart-On Main command will automatically set the auxiliary
output to inactive. Depending on the currently valid device status settings, the transistor at the control
output may change state (see Status Read/Write command). If the Smart-On Main command is terminated
by a 1-Wire reset pulse while receiving the reset stimulus, the DS2409 will immediately turn off the
pulldown transistor and let the output line go high.
SMART-ON AUXILIARY [33h]
This command works essentially the same way as the Smart-On Main command, but it affects the
auxiliary 1-Wire output. After the reset response byte is received by the bus master, the auxiliary output is
Not Recommended for New Design
DS2409
FUNCTION COMMAND FLOW CHART Figure 5
Not Recommended for New Design
DS2409
FUNCTION COMMAND FLOW CHART Figure 5 (cont’d)
Not Recommended for New Design
DS2409
HARDWARE CONFIGURATION Figure 6
1-WIRE BUS SYSTEM
The 1-Wire bus is a system which has a single bus master and one or more slaves. In all instances the
DS2409 behaves as a slave. The discussion of this bus system is broken down into three topics: hardware
configuration, transaction sequence, and 1-Wire signaling (signal types and timing). A 1-Wire protocol
defines bus transactions in terms of the bus state during specified time slots that are initiated on the
falling edge of sync pulses from the bus master. For a more detailed protocol description, refer to Chapter
4 of the Book of DS19xx iButton Standards.
Hardware Configuration
The 1-Wire bus has only a single line by definition; it is important that each device on the bus be able to
drive it at the appropriate time. To facilitate this, each device attached to the 1-Wire bus must have open-
drain or 3-state outputs. The 1-Wire input of the DS2409 is open drain with an internal circuit equivalent
to that shown in Figure 6. A multidrop bus consists of a 1-Wire bus with multiple slaves attached. The 1-
Wire bus has a maximum data rate of 16.3kbits per second and requires a pullup resistor of approximately
1.5kΩ or a DS2480 driver for MicroLAN applications.
The idle state for the 1-Wire bus is high. If for any reason a transaction needs to be suspended, the bus
MUST be left in the idle state if the transaction is to resume. If this does not occur and the bus is left low
for more than 120µs, one or more of the devices on the bus may be reset. The DS2409 may perform a
power-on reset cycle and deactivate both 1-Wire outputs if the 1-Wire input is low for minimum 8ms. A
low time of 12ms or more will always cause a power-on reset cycle.
Transaction Sequence
The protocol for accessing the DS2409 via the 1-Wire port is as follows:InitializationROM Function CommandControl Function Command
INITIALIZATION
All transactions on the 1-Wire bus begin with an initialization sequence. The initialization sequence
consists of a reset pulse transmitted by the bus master followed by presence pulse(s) transmitted by the
slave(s). The presence pulse lets the bus master know that the DS2409 is on the bus and is ready to
operate. For more details, see the “1-Wire Signaling” section.
Not Recommended for New Design
