MAXIM DS2413 User Manual

19-5316; 7/10

www.maxim-ic.com

GENERAL DESCRIPTION

The DS2413 is a dual-channel programmable I/O

1-Wire

chip. The PIO outputs are configured as open-drain and provide up to 20mA continuous sink capability and off-state operating voltage up to 28V. Control and sensing of the PIO pins is performed with a dedicated device-level command protocol. To provide a high level of fault tolerance in the end application, the 1-Wire IO and PIO pins are all capable of withstanding continuous application of voltages up to 28V max. Communication and operation of the DS2413 is performed with the single contact Maxim/Dallas 1-Wire serial interface.

APPLICATIONS

 LED Control  Accessory Identification and Control  General Purpose Input/Output  Key-Pick Systems  Industrial Controllers  System Monitoring

TYPICAL OPERATING CIRCUIT

PUP

PX.Y

µC

mands, Registers, and Modes are capitalized for

Com clarity.

1-Wire is a registered trademark of Maxim Integrated Products, Inc.

DS2413

GND

PIOA

PIOB

LED

Switch

Local Power

DS2413

1-Wire Dual Channel

Addressable Switch

FEATURES

 Open-Drain Programmable I/O Pins  PIO Pins Support 20mA max Continuous Current

Sink

 Supports 28V (max) PIO Pin Operating Voltage  On-Resistance of PIO Pulldown Transistor 20

max; OFF Resistance 1M min

 Parasitic Power Supply Through 1-Wire  Communicates to Host with a Single Digital

Signal at 14.9kb or 100kbps Using 1-Wire Protocol

 Unique 64-bit ROM Serial Number Factory

Lasered Into Each Device

 Switchpoint Hysteresis and Filtering to Optimize

Performance in the Presence of Noise

 1-Wire IO Pin Supports 28V Absolute Maximum

DC Level for Fault Conditions

 Operates Over a Wide 1-Wire Voltage Range of

2.8V to 5.25V from 0°C to +70°C

 High ESD Immunity of 1-Wire IO Pin: 8kV HBM

Typical

 TSOC and TDFN Packages Available

ORDERING INFORMATION

PART TEMP RANGE PIN-PACKAGE

DS2413P+ 0°C to +70°C TSOC DS2413P+T&R 0°C to +70°C TSOC DS2413Q+T&R 0°C to +70°C TDFN

+ Denotes a lead(Pb)-free package/RoHS-compliant package. T&R = Tape and reel.

PIN CONFIGURATION

TSOC TDFN

ywwrr

Exposed Paddle

413

mrrF

Top View with Marking. TDFN Contacts

2413

Not Visible in this View.

Note: Some revisions of this device may incorporate deviations from published specifications known as errata. Multiple revisions of any device may be simultaneously available through various sales channels. For information about device errata, click here: www.maxim-ic.com/errata

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DS2413: 1-Wire Dual Channel Addressable Switch

ABSOLUTE MAXIMUM RATINGS

Voltage on Any Pin to GND -0.5V, +30V Maximum Current into IO Pin Maximum Current into PIO Pin Maximum Current Through GND Pins (Both Pins Tied Together) Operating Temperature Range 0°C to +70°C Junction Temperature +150°C Storage Temperature Range -55°C to +125°C Lead Temperature (soldering, 10s) Soldering Temperature (reflow)

Stresses beyond those listed under “Absolute Maximum Ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated in the operational sections of the specifications is not implied. Exposure to the absolute maximum rating conditions for extended periods may affect device reliability.

ELECTRICAL CHARACTERISTICS T

= 0°C to +70°C

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

IO PIN GENERAL DATA

1-Wire Pullup Voltage (Note 1)

1-Wire Pullup Resistance

Input Load Current I

PUP

Standard speed 2.8 5.25 Overdrive speed 2.9 5.25 DC only; no 1-Wire communication 28 (Notes 1, 2)

 5.25V

PUP

 3.30V

PUP

1.5 2.2

3.5 70

3.5 15

V(IO) = 28V (Note 3) 400 950 Input Capacitance CIO At 25°C (Notes 4, 5) 800 pF Input Low Voltage V High-to-Low Switching Threshold Low-to-High Switching Threshold Switching Hysteresis V Output Low Voltage V

Recovery Time (Notes 1, 12)

(Notes 5, 13)

Time slot Duration (Note 1, 5)

REC

REH

SLOT

(Notes 1, 6) 0.4 V

(Notes 5, 7, 8) 0.4 3.2 V

(Notes 5, 7, 9) 0.7 3.6 V

(Notes 5, 10) 0.2 V

At 4mA Current Load (Note 11)

Standard speed, R

Overdrive speed, R

PUP

= 2.2k

= 2.2k Overdrive speed, directly prior to reset pulse; R

PUP

= 2.2k

0.4 V 5 2

Standard speed 0.5 5.0 Rising-Edge Hold-off Time Overdrive speed Not applicable (0) Standard speed, V

PUP

 4.5V

65 Standard speed (Note 14) 67 Overdrive speed, V (Note 14)

PUP

 4.5V

Overdrive speed (Note 14) 10

IO PIN, 1-Wire RESET, PRESENCE DETECT CYCLE

480 960

48 80

63 80

7.0

8.2

0 0.7

Reset Low Time (Note 1) t

Presence Detect High Time (Notes 14, 15)

Presence Detect Fall Time (Notes 5, 16)

RSTL

PDH

FPD

Standard speed, V Standard speed (Note 14) 600 960 Overdrive speed, V

PUP

 4.5V

 4.5V Overdrive speed (Note 14) Standard speed, V Standard speed 15 68 Overdrive speed, V

PUP

 4.5V

 4.5V Overdrive speed 2 Standard speed, V Standard speed 0.24 1.6 Overdrive speed, V

> 4.5V 0.24 1.4

PUP

 4.5V

PUP

Overdrive speed 0 0.9

Presence Detect Low Time (Note 15)

PDL

Standard speed, V Standard speed (Note 14) 60 260 Overdrive speed, V (Note 14) Overdrive speed (Note 14) 8

> 4.5V 60 240

PUP

 4.5V

PUP

25mA 30mA 60mA

+300°C +260°C

k

µA

µs

2 of 18

DS2413: 1-Wire Dual Channel Addressable Switch

PARAMETER SYMBOL CONDITIONS MIN TYP MAX UNITS

Presence Detect Sample Time (Notes 1, 20)

MSP

Standard speed, V Standard speed 69.6 75 Overdrive speed, V

> 4.5V 67.4 75

PUP

 4.5V

7.7 10

µs

Overdrive speed 9.1 10

IO PIN, 1-Wire WRITE

Write-0 Low Time (Notes 1, 17)

W0L

Standard speed, V Standard speed (Note 14) 62 120 Overdrive speed, V (Note 14)

> 4.5V 60 120

PUP

 4.5V

PUP

7 16

µs

Overdrive speed (Note 14) 8 16

(Notes 1, 17)

W1L

Standard speed 5 15 Write-1 Low Time Overdrive speed 1 2

µs

IO PIN, 1-Wire READ Read Low Time

(Notes 1, 18) Read Sample Time

(Notes 1, 18)

MSR

Standard speed 5 Overdrive speed 1 Standard speed Overdrive speed

+ 

15 2

15 - 

2 - 

µs

PIO Pins

Leakage Current ILP Pin at 28V (Note 19) 8.5 24 µA Input Capacitance CP (Note 5) 100 pF Output low voltage V Input Low Voltage V Input High Voltage (Note 21)

OLP

ILP

IHP

20mA load current 0.4 V (Note 1) 0.8 V

–

(Note 1)

PUP

0.3V

28 V

Note 1: System requirement. Note 2: Full R

Maximum allowable pullup resistance is a function of the number of 1-Wire devices in the system and 1-Wire recovery times. The specified value here applies to systems with only one device and with the minimum 1-Wire recovery times. For more heavily loaded systems, an active pullup such as that found in the DS2482-x00 or DS2480B may be required. The DS2482-x00 may not always detect the DS2413 presence pulse. For proper operation it may be necessary to disregard (force to 1) the PPD bit in the DS2482-x00 status register.

Note 3: The I-V characteristic is linear for voltages greater than 10V. Note 4:

Capacitance on the data pin could be 800pF when V after V

Note 5: Guaranteed by design and simulation. Not production tested. Note 6: The voltage on IO needs to be less than or equal to V Note 7: V

Note 8: Voltage below which, during a falling edge on IO, a logic 0 is detected. Note 9: Voltage above which, during a rising edge on IO, a logic 1 is detected. Note 10: After V Note 11: The I-V characteristic is linear for voltages less than 1V. Note 12: Applies to a single DS2413 attached to a 1-Wire line. Note 13: The earliest recognition of a negative edge is possible at t Note 14: Highlighted numbers are NOT in compliance with legacy 1-Wire product standards. See comparison table below. Note 15: t

pulse. t

Note 16: Interval during the negative edge on IO at the beginning of a Presence Detect pulse between the time at which the voltage is

80% of V

Note 17:

 in Figure 12 represents the time required for the pullup circuitry to pull the voltage on IO up from V duration for the master to pull the line low is t

Note 18:

 in Figure 12 represents the time required for the pullup circuitry to pull the voltage on IO up from V of the bus master. The actual maximum duration for the master to pull the line low is t

Note 19: The I-V characteristic is linear for voltages greater than 7V. Note 20: t

Note 21: Production tested for V

range guaranteed by design and simulation. not production tested. Production testing performed at a fixed R

PUP

is first applied. If a 2.2k resistor is used to pull up the data line, 2.5µs

has been applied the parasite capacitance will not affect normal communications.

PUP

and VTH are functions of the internal supply voltage, which is a function of V

maximum specifications are valid at V

is crossed during a rising edge on IO, the voltage on IO has to drop by at least VHY to be detected as logic '0'.

is deemed to have ended when the voltage on IO drops below 80% of V

PDH

MSP

PDH

is deemed to have begun when the voltage on IO drops below 20% of V

PDL

and the time at which the voltage is 20% of V

PUP

is a system required sample point and not directly production tested. Production testing is performed on related parameters and t

. Parameter t

PDL

is guaranteed by design and simulation, not production tested.

FPD

. V

IHP(min)

IHP(max)

PUPmax

is guaranteed by design and simulation, not production tested.

PUP

whenever the master drives the line low.

ILMAX

(5.25V). In any case, VTL < VTH < V

after VTH has been previously reached.

REH

PUP

W1Lmax

+ tF -  and t

+ tF -  respectively.

W0Lmax

and the 1-Wire Recovery Times. The VTH and

PUP

on the leading edge of the presence-detect low

PUP

on the leading edge of the pulse.

PUP

to VTH. The actual maximum

to the input high threshold

RLmax

+ tF.

PUP

value.

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DS2413: 1-Wire Dual Channel Addressable Switch

LEGACY VALUES DS2413 VALUES

PARAMETER STANDARD SPEED OVERDRIVE SPEED STANDARD SPEED OVERDRIVE SPEED

MIN MAX MIN MAX MIN MAX MIN MAX

SLOT

RSTL

PDH

PDL

W0L

(incl. t

REC)

61µs (undef.) 7µs (undef.) 67µs (undef.) 10µs (undef.)

480µs (undef.) 48µs 80µs 600µs 960µs 63µs 80µs

15µs 60µs 2µs 6µs 15µs 68µs 2µs 8.2µs 60µs 240µs 8µs 24µs 60µs 260µs 8µs 32µs 60µs 120µs 6µs 16µs 62µs 120µs 8µs 16µs

PIN DESCRIPTION

NAME TSOC PIN # TDFN PIN # FUNCTION

IO 2 2 1-Wire bus interface. Open-drain, requires external pullup resistor.

PIOA 6 4 Programmable I/O pin, open-drain with weak pulldown, power-on

default is off (PIOA = 1).

PIOB 4 6 Programmable I/O pin, open-drain with weak pulldown, power-on

default is off (PIOB = 1). GND1 1 3 Ground reference 1 GND2 5 5 Ground reference 2; both GND pins must be connected in the

application.

NC 3 1 Not connected

Exposed Paddle (TDFN only). Solder evenly to the board’s ground

GND — EP

plane for proper operation. See Application Note 3273 for additional

information.

DESCRIPTION

The DS2413 combines two PIO pins and a fully featured 1-Wire interface in a single chip. PIO outputs are opendrain, operate at up to 28V and provide an on resistance of 20 max. A robust communication protocol ensures that PIO output changes occur error-free. Each DS2413 has a Registration Number that is 64 bits long. The Registration Number guarantees unique identification and is used to address the device in a multidrop 1-Wire network environment, where multiple devices reside on a common 1-Wire bus and operate independently of each other. Device power is supplied parasitically from the 1-Wire bus. The DS2413’s applications of include accessory identification and control, system monitoring, and general-purpose input/output.

OVERVIEW

The block diagram in Figure 1 shows the relationships between the major sections of the DS2413. The DS2413 has two main components: 64-bit Registration Number, and PIO Control. The hierarchical structure of the 1-Wire protocol is shown in Figure 2. The bus master must first provide one of the seven ROM Function Commands, 1) Read ROM, 2) Match ROM, 3) Search ROM, 4) Skip ROM, 5) Resume, 6) Overdrive-Skip ROM or 7) OverdriveMatch ROM. Upon completion of an Overdrive ROM command byte executed at standard speed, the device enters Overdrive mode where all subsequent communication occurs at a higher speed. The protocol required for these ROM function commands is described in Figure 10. After a ROM function command is successfully executed, the PIO functions become accessible and the master may provide one of the two PIO Function commands. The protocol for these commands is described in Figure 6. All data is read and written least significant bit first.

Figure 1. Block Diagram

Internal V

1-Wire

Interface

PIO

Control

64-Bit Registration

Number

4 of 18

PIOB

PIOA

DS2413: 1-Wire Dual Channel Addressable Switch

64-BIT LASERED ROM

Each DS2413 has a unique ROM Registration Number that is 64 bits long, as shown in Figure 3. 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 (Cyclic Redundancy Check) of the first 56 bits. The 1-Wire CRC is generated using a polynomial generator consisting of a shift register and XOR gates as shown in Figure 4. The polynomial is X

+ X5 + X4 + 1. Additional information about the Dallas 1-Wire CRC is available in Application Note 27. The shift register bits are initialized to zero. Then starting with the LSB of the family code, one bit at a time is shifted in. After the 8th bit of the family code has been entered, then the serial number is entered. After the 48th bit of the serial number has been entered, the shift register contains the CRC value. Shifting in the eight bits of CRC should return the shift register to all zeros.

Figure 2. Hierarchical Structure for 1-Wire Protocol

DS2413

Command Level:

1-Wire ROM Function

Commands (see Figure 10)

DS2413-specific

PIO Function Commands

(see Figure 6)

Figure 3. 64-Bit LASERED ROM

MSB LSB

8-Bit CRC Code 48-Bit Serial Number

MSB LSB MSB LSB MSB LSB

Figure 4. 1-Wire CRC Generator

Available Commands:

Read ROM Match ROM Search ROM Skip ROM Resume Overdrive Skip Overdrive Match

PIO Access Read PIO Access Write

Command Codes:

33h 55h F0h CCh

3Ch 69h

F5h 5Ah

Data Field Affected:

64-bit Reg. #, RC-Flag 64-bit Reg. #, RC-Flag 64-bit Reg. #, RC-Flag RC-Flag RC-Flag RC-Flag, OD-Flag 64-bit Reg. #, RC-Flag,

PIO Pins PIO Pins

8-Bit Family Code (3Ah)

OD-Flag

Polynomial = X8 + X5 + X4 + 1

STAGE

INPUT DATA

STAGE

5 of 18

DS2413: 1-Wire Dual Channel Addressable Switch

PIO STUCTURE

Each PIO consists of an open-drain pulldown transistor with 28V capability. The transistor is controlled by the PIO Output Latch, as shown in Figure 5. The PIO Control unit connects the PIOs to the 1-Wire interface.

Figure 5. PIO Simplified Logic Diagram

PIO Pin

State

PIO Output

Latch State.

PIO Pin

PIO Data

PIO Clock

CLOCK

PIO Out-

ut Latch

PIO FUNCTION COMMANDS

The PIO Function Flow Chart (Figure 6) describes the protocols necessary to access the PIO pins of the DS2413. Examples on how to use these functions are included at the end of this document. The communication between master and DS2413 takes place either at standard speed (default, OD = 0) or at Overdrive Speed (OD = 1). If not explicitly set into the Overdrive Mode, the DS2413 powers up in standard speed.

PIO ACCESS READ [F5h]

This command reads the PIO logical status and reports it together with the state of the PIO Output Latch in an endless loop. A PIO Access Read can be terminated at any time with a 1-Wire Reset.

PIO Status Bit Assignment

b7 b6 b5 b4 b3 b2 b1 b0

Complement of b3 to b0

The state of both PIO channels is sampled at the same time. The first sampling occurs during the last (most significant) bit of the command code F5h. The PIO status is then reported to the bus master. While the master receives the last (most significant) bit of the PIO status byte, the next sampling occurs and so on until the master generates a 1-Wire Reset. The sampling occurs with a delay of t previous byte, as shown in Figure 7. The value of "x" is approximately 0.2µs.

PIOB Output

Latch State

Figure 7. PIO Access Read Timing Diagram

MS 2 bits of previous byte

PIOB Pin

State

PIOA Output

Latch State

+x from the rising edge of the MS bit of the

REH

LS 2 bits of PIO Status byte

PIOA Pin

State

REH

Sampling Point

Notes:

1 2 The sample point timing also applies to the PIO Access Write command, with the "previous byte" being the

The "previous byte" could be the command code or the data byte resulting from the previous PIO sample.

write confirmation byte (AAh).

6 of 18

Figure 6. PIO Function Flow Chart

)1)

Bus Master TX Memory

Function Command

DS2413: 1-Wire Dual Channel Addressable Switch

From ROM Functions

Flow Chart (Figure 10)

Note 1)

See the command description for the exact timing of the PIO pin sampling and updating.

DS2413 Samples

PIO Pin Status

F5h

PIO Access

Read?

5Ah

PIO Access

Write?

Bus Master TX new

PIO Output Data Byte

Bus Master TX inverted new PIO Output Data B

Transmission

OK?

DS2413 Updates PIO Output Latch

Bus Master RX

Confirmation AAh

Bus Master

RX “1”s

Master

TX Reset?

Bus Master RX

PIO Pin Status

Master

TX Reset?

To ROM Functions

Flow Chart (Figure 10)

7 of 18

DS2413 Samples

PIO Pin Status

Bus Master RX

PIO Pin Status

Master

TX Reset?

DS2413: 1-Wire Dual Channel Addressable Switch

PIO ACCESS WRITE [5Ah]

The PIO Access Write command writes to the PIO output latches, which control the pulldown transistors of the PIO channels. In an endless loop this command first writes new data to the PIO and then reads back the PIO status. This implicit read-after-write can be used by the master for status verification. A PIO Access Write can be terminated at any time with a 1-Wire Reset.

PIO Output Data Bit Assignment

b7 b6 b5 b4 b3 b2 b1 b0

X X X X X X PIOB PIOA

After the command code the master transmits a PIO Output Data byte that determines the new state of the PIO output transistors. The first (least significant) bit is associated to PIOA; the next bit affects PIOB. The other 6 bits of the new state byte do not have corresponding PIO pins. These bits should always be transmitted as "1"s. To switch the output transistor on, the corresponding bit value is 0. To switch the output transistor off (non-conducting) the bit must be 1. This way the bit transmitted as the new PIO output state arrives in its true form at the PIO pin. To protect the transmission against data errors, the master must repeat the PIO Output Data byte in its inverted form. Only if the transmission was error-free will the PIO status change. The actual PIO transition to the new state occurs with a delay of t of "x" is approximately 0.2µs. To inform the master about the successful communication of the PIO byte, the DS2413 transmits a confirmation byte with the data pattern AAh. While the MS bit of the confirmation byte is transmitted, the DS2413 samples the state of the PIO pins, as shown in Figure 7, and sends it to the master. The master can either continue writing more data to the PIO or issue a 1-Wire Reset to end the command.

Figure 8. PIO Access Write Timing Diagram

+x from the rising edge of the MS bit of the inverted PIO byte, as shown in Figure 8. The value

REH

MS 2 bits of inverted PIO Output Data byte

PIO

REH

LS 2 bits of confir-

mation byte (AAh)

1-Wire BUS SYSTEM

The 1-Wire bus is a system that has a single bus master and one or more slaves. In all instances the DS2413 is a slave device. The bus master is typically a microcontroller. The discussion of this bus system is broken down into three topics: hardware configuration, transaction sequence, and 1-Wire signaling (signal types and timing). The 1-Wire protocol defines bus transactions in terms of the bus state during specific time slots, which are initiated on the falling edge of sync pulses from the bus master.

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 tri-state outputs. The 1-Wire port of the DS2413 is open drain with an internal circuit equivalent to that shown in Figure 9.

A multidrop bus consists of a 1-Wire bus with multiple slaves attached. The DS2413 supports both a Standard and Overdrive communication speed of 14.9kbps (max) and 100kbps (max), respectively. Note that legacy 1-Wire products support a standard communication speed of 16.3kbps and Overdrive of 142kbps. The value of the pullup resistor primarily depends on the network size and load conditions. The DS2413 requires a pullup resistor of 2.2k (max) at any speed.

8 of 18

DS2413: 1-Wire Dual Channel Addressable Switch

The idle state 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 16µs (Overdrive speed) or more than 120µs (standard speed), one or more devices on the bus may be reset.

for the 1-Wire bus is high. If for any reason a transaction needs to be suspended, the bus MUST be

Figure 9. Hardware Configuration

BUS MASTER DS2413 1-Wire PORT

PUP

Open Drain

Port Pin

RX = RECEIVE

TX = TRANSMIT

100 MOSFET

RXDATA



TRANSACTION SEQUENCE

The protocol for accessing the DS2413 through the 1-Wire port is as follows:

 Initialization  ROM Function Command  PIO Function Command  Data

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 DS2413 is on the bus and is ready to operate. For more details, see the 1- Wire Signaling section.

1-Wire ROM FUNCTION COMMANDS

Once the bus master has detected a presence, it can issue one of the seven ROM function commands that the DS2413 supports. All ROM function commands are 8 bits long. A list of these commands follows (refer to the flow chart in Figure 10).

READ ROM [33h]

This command allows the bus master to read the DS2413’s 8-bit family code, unique 48-bit serial number, and 8-bit CRC. This command can only be used if there is a single slave on the bus. If more than one slave is present on the bus, a data collision occurs when all slaves try to transmit at the same time (open drain produces a wired-AND result). The resultant family code and 48-bit serial number result in a mismatch of the CRC.

MATCH ROM [55h]

The Match ROM command, followed by a 64-bit ROM sequence, allows the bus master to address a specific DS2413 on a multidrop bus. Only the DS2413 that exactly matches the 64-bit ROM sequence, including the external address, responds to the following PIO Function command. All other slaves wait for a reset pulse. This command can be used with a single or multiple devices on the bus.

9 of 18

DS2413: 1-Wire Dual Channel Addressable Switch

SEARCH ROM [F0h]

When a system is initially brought up, the bus master might not know the number of devices on the 1-Wire bus or their device ID numbers. By taking advantage of the wired-AND property of the bus, the master can use a process of elimination to identify the device ID numbers of all slave devices. For each bit of the device ID number, starting with the least significant bit, the bus master issues a triplet of time slots. On the first slot, each slave device participating in the search outputs the true value of its device ID number bit. On the second slot, each slave device participating in the search outputs the complemented value of its device ID number bit. On the third slot, the master writes the true value of the bit to be selected. All slave devices that do not match the bit written by the master stop participating in the search. If both of the read bits are zero, the master knows that slave devices exist with both states of the bit. By choosing which state to write, the bus master branches in the ROM code tree. After one complete pass, the bus master knows the device ID number of a single device. Additional passes identify the device ID numbers of the remaining devices. Refer to Application Note 187: 1-Wire Search Algorithm for a detailed discussion, including an example. Since with the DS2413 the ROM CRC is not valid if one or more address inputs are tied to GND, it is recommended to do a double search when building a list of devices on the 1-Wire line.

SKIP ROM [CCh]

This command can save time in a single-drop bus system by allowing the bus master to access the PIO functions without providing the 64-bit ROM code. If more than one slave is present on the bus and, for example, a read command is issued following the Skip ROM command, data collision occurs on the bus as multiple slaves transmit simultaneously (open-drain pulldowns produce a wired-AND result).

RESUME [A5h]

To maximize the data throughput in a multidrop environment, the Resume function is available. This function checks the status of the RC bit and, if it is set, directly transfers control to the PIO functions, similar to a Skip ROM command. The only way to set the RC bit is through successfully executing the Match ROM, Search ROM, or Overdrive Match ROM command. Once the RC bit is set, the device can repeatedly be accessed through the Resume Command function. Accessing another device on the bus clears the RC bit, preventing two or more devices from simultaneously responding to the Resume Command function.

OVERDRIVE SKIP ROM [3Ch]

On a single-drop bus this command can save time by allowing the bus master to access the PIO functions without providing the 64-bit ROM code. Unlike the normal Skip ROM command, the Overdrive Skip ROM sets the DS2413 in the Overdrive mode (OD = 1). All communication following this command has to occur at Overdrive speed until a reset pulse of minimum 480µs duration resets all devices on the bus to standard speed (OD = 0).

When issued on a multidrop bus, this command sets all Overdrive-supporting devices into Overdrive mode. To subsequently address a specific Overdrive-supporting device, a reset pulse at Overdrive speed has to be issued followed by a Match ROM or Search ROM command sequence. This speeds up the time for the search process. If more than one slave supporting Overdrive is present on the bus and the Overdrive Skip ROM command is followed by a Read command, data collision occurs on the bus as multiple slaves transmit simultaneously (open-drain pulldowns produce a wired-AND result).

OVERDRIVE MATCH ROM [69h]

The Overdrive Match ROM command followed by a 64-bit ROM sequence transmitted at Overdrive Speed allows the bus master to address a specific DS2413 on a multidrop bus and to simultaneously set it in Overdrive mode. Only the DS2413 that exactly matches the 64-bit ROM sequence responds to the subsequent PIO Function command. Slaves already in Overdrive mode from a previous Overdrive Skip or successful Overdrive Match command remain in Overdrive mode. All overdrive-capable slaves return to standard speed at the next Reset Pulse of minimum 480µs duration. The Overdrive Match ROM command can be used with a single or multiple devices on the bus.

10 of 18

Figure 10-1. ROM Functions Flow Chart

From PIO Functions

Flow Chart (Figure 6)

Bus Master TX

Reset Pulse

Reset Pulse ?

DS2413: 1-Wire Dual Channel Addressable Switch

From Figure 10, 2

OD = 0

Par

Bus Master TX ROM

Function Command

33h

Read ROM

Command ?

RC = 0

DS2413 TX

Family Code

(1 Byte)

DS2413 TX

Serial Number

(6 Bytes)

Presence Pulse

55h

Match ROM

Command ?

RC = 0

Master TX Bit 0

Bit 0

Match ?

Master TX Bit 1

Bit 1

Match ?

DS2413 TX

F0h

Search ROM

Command ?

YY Y Y

RC = 0

DS2413 TX Bit 0

Master TX Bit 0

Bit 0

Match ?

DS2413 TX Bit 1

Master TX Bit 1

Bit 1

Match ?

To Figure 10

CCh

Part

Skip ROM

Command ?

RC = 0

DS2413 TX

CRC Byte

Master TX Bit 63

DS2413 TX Bit 63

Master TX Bit 63

DS2413 TX Bit 63

Bit 63

Match ?

RC = 1

To PIO Functions Flow

Chart (Figure 6)

Bit 63

Match ?

RC = 1

To Figure 10

Part

From Figure 10

Part

11 of 18

DS2413: 1-Wire Dual Channel Addressable Switch

Figure 10-2. ROM Functions Flow Chart (continued)

To Figure 10, 1

From Figure 10

Part

A5h

Resume

Command ?

RC = 1 ?

3Ch

Overdrive

Skip ROM ?

RC = 0 ; OD = 1

69h

Overdrive Match

ROM ?

RC = 0 ; OD = 1

Master TX Bit 0

Master

TX Reset ?

Bit 0

Match ?

From Figure 10

Part

To Figure 10

Part

Master

TX Reset ?

Master TX Bit 1

Bit 1

Match ?

Master TX Bit 63

Bit 63

Match ?

RC = 1

12 of 18

DS2413: 1-Wire Dual Channel Addressable Switch



1-Wire SIGNALING

The DS2413 requires strict protocols to ensure data integrity. The protocol consists of four types of signaling on one line: Reset Sequence with Reset Pulse and Presence Pulse, Write-Zero, Write-One, and Read-Data. Except for the Presence pulse, the bus master initiates all falling edges. The DS2413 can communicate at two different speeds, standard speed, and Overdrive Speed. If not explicitly set into the Overdrive mode, the DS2413 communicates at standard speed. While in Overdrive Mode the fast timing applies to all waveforms.

To get from idle to active, the voltage on the 1-Wire line needs to fall from V from active to idle, the voltage needs to rise from V

past the threshold VTH. The time it takes for the voltage to

ILMAX

make this rise is seen in Figure 11 as '' and its duration depends on the pullup resistor (R capacitance of the 1-Wire network attached.

The voltage V

is relevant for the DS2413 when determining a

ILMAX

logical level, not triggering any events.

Figure 11 shows the initialization sequence required to begin any communication with the DS2413. A Reset Pulse followed by a Presence Pulse indicates the DS2413 is ready to receive data, given the correct ROM and PIO Function command. If the bus master uses slew-rate control on the falling edge, it must pull down the line for t

to compensate for the edge. A t

+ t

to standard speed. If the DS2413 is in Overdrive Mode and t Overdrive Mode. If the device is in Overdrive Mode and t

duration of 480µs or longer exits the Overdrive Mode, returning the device

RSTL

is no longer than 80µs, the device remains in

RSTL

is between 80µs and 480µs, the device will reset, but

the communication speed is undetermined.

Figure 11. Initialization Procedure: Reset and Presence Pulse

below the threshold VTL. To get

PUP

) used and the

PUP

RSTL

MASTER TX “RESET PULSE” MASTER RX “PRESENCE PULSE”

MSP

IHMASTER

PUP

ILMAX

RSTL

PDH

PDL

RSTH

REC

RESISTOR MASTER DS2413

After the bus

master has released the line it goes into receive mode. Now the 1-Wire bus is pulled to V the pullup resistor, or in case of a DS2482-x00 or DS2480B driver, by active circuitry. When the threshold V crossed, the DS2413 waits for t presence pulse, the master must test the logical state of the 1-Wire line at t

and then transmits a Presence Pulse by pulling the line low for t

PDH

MSP

PDL

The t

window must be at least the sum of t

RSTH

DS2413 is ready for data communication. In a mixed population network, t

PDHMAX

, t

PDLMAX

, and t

. Immediately after t

RECMIN

should be extended to minimum

RSTH

is expired, the

RSTH

480µs at standard speed and 48µs at Overdrive speed to accommodate other 1-Wire devices.

through

PUP

. To detect a

13 of 18

DS2413: 1-Wire Dual Channel Addressable Switch



Read/Write Time Slots

Data communication with the DS2413 takes place in time slots, which carry a single bit each. Write-time slots transport data from bus master to slave. Read-time slots transfer data from slave to master. Figure 12 illustrates the definitions of the write- and read-time slots.

All communication begins with the master pulling the data line low. As the voltage on the 1-Wire line falls below the threshold V a write-time slot and how long data is valid during a read-time slot.

Figure 12. Read/Write Timing Diagram

Write-One Time Slot

, the DS2413 starts its internal timing generator that determines when the data line is sampled during

W1L

IHMASTER

PUP

ILMAX



SLOT

Write-Zero Time Slot

PUP

IHMASTER

ILMA

RESISTOR MASTER

Read-Data Time Slot

PUP

IHMASTER

ILMAX

RESISTOR MASTER

W0L

SLOT

MSR

Master

Sampling

Window



SLOT

REC

RESISTOR MASTER DS2413

14 of 18

DS2413: 1-Wire Dual Channel Addressable Switch

Master-to-Slave

For a write-one time slot, the voltage on the data line must have crossed the VTH threshold before the write-one low time t threshold until the write-zero low time t data line should not exceed V the DS2413 needs a recovery time t

is expired. For a write-zero time slot, the voltage on the data line must stay below the VTH

W1LMAX

is expired. For the most reliable communication, the voltage on the

W0LMIN

during the entire t

ILMAX

before it is ready for the next time slot.

REC

W0L

or t

window. After the V

W1L

threshold has been crossed,

Slave-to-Master

A read-data time slot begins like a write-one time slot. The voltage on the data line must remain below VTL until the read low time t

is expired. During the tRL window, when responding with a 0, the DS2413 starts pulling the data

line low; its internal timing generator determines when this pulldown ends and the voltage starts rising again. When responding with a 1, the DS2413 does not hold the data line low at all, and the voltage starts rising as soon as t

over.

The sum of t the master sampling window (t most reliable communication, t later than t sufficient recovery time t applies only to a single DS2413 attached to a 1-Wire line. For multidevice configurations, t

+  (rise time) on one side and the internal timing generator of the DS2413 on the other side define

. After reading from the data line, the master must wait until t

MSRMAX

for the DS2413 to get ready for the next time slot. Note that t

REC

to t

MSRMIN

should be as short as permissible, and the master should read close to but no

) in which the master must perform a read from the data line. For the

MSRMAX

is expired. This guarantees

SLOT

specified herein

REC

needs to be

REC

extended to accommodate the additional 1-Wire device input capacitance. Alternatively, an interface that performs active pullup during the 1-Wire recovery time such as the DS2482-x00 or DS2480B 1-Wire line drivers can be used.

IMPROVED NETWORK BEHAVIOR (SWITCHPOINT HYSTERESIS)

In a 1-Wire environment, line termination is possible only during transients controlled by the bus master (1-Wire driver). 1-Wire networks, therefore, are susceptible to noise of various origins. Depending on the physical size and topology of the network, reflections from end points and branch points can add up, or cancel each other to some extent. Such reflections are visible as glitches or ringing on the 1-Wire communication line. Noise coupled onto the 1-Wire line from external sources can also result in signal glitching. A glitch during the rising edge of a time slot can cause a slave device to lose synchronization with the master and, consequently, result in a search ROM command coming to a dead end or cause a device-specific function command to abort. For better performance in network applications, the DS2413 uses a new 1-Wire front end, which makes it less sensitive to noise and also reduces the magnitude of noise injected by the slave device itself.

The 1-Wire front end of the DS2413 differs from traditional slave devices in four characteristics.

1) The falling edge of the presence pulse has a controlled slew rate. This provides a better match to the line

impedance than a digitally switched transistor, converting the high-frequency ringing known from traditional devices into a smoother low-bandwidth transition. The slew-rate control is specified by the parameter t which has different values for standard and Overdrive speed.

2) There is additional low-pass filtering in the circuit that detects the falling edge at the beginning of a time slot.

This reduces the sensitivity to high-frequency noise. This additional filtering does not apply at Overdrive speed.

3) There is a hysteresis at the low-to-high switching threshold V

below V

- VHY, it will not be recognized (Figure 13, Case A). The hysteresis is effective at any 1-Wire speed.

4) There is a time window specified by the rising edge hold-off time t

they extend below V appear late after crossing the V

- VHY threshold (Figure 13, Case B, tGL < t

threshold and extend beyond the t

taken as the beginning of a new time slot (Figure 13, Case C, t

Devices that have the parameters t

, VHY, and t

FPD

specified in their electrical characteristics use the improved 1-

REH

. If a negative glitch crosses VTH but does not go

during which glitches are ignored, even if

REH

). Deep voltage droops or glitches that

REH

window cannot be filtered out and are

REH

 t

REH

Wire front end.

FPD

15 of 18

DS2413: 1-Wire Dual Channel Addressable Switch

Figure 13. Noise Suppression Scheme

PUP

Case A Case CCase B

REH

COMMAND-SPECIFIC 1-Wire COMMUNICATION PROTOCOL—LEGEND

SYMBOL DESCRIPTION

RST 1-Wire Reset Pulse generated by master.

PD 1-Wire Presence Pulse generated by slave.

Select Command and data to satisfy the ROM function protocol.

PIOR Command "PIO Access Read".

PIOW Command "PIO Access Write".

FF loop Indefinite loop where the master reads FF bytes.

COMMAND-SPECIFIC 1-Wire COMMUNICATION PROTOCOL—COLOR CODES

Master to slave Slave to master

PIO ACCESS READ (CANNOT FAIL)

RST PD Select PIOR <PIO Status Byte>

Continues until master sends Reset Pulse

PIO ACCESS WRITE (SUCCESS)

RST PD Select PIOW <PIO Output data> <PIO Output data> <AAh> <PIO Status Byte>

Loop until master sends Reset Pulse

PIO ACCESS WRITE (INVALID DATA BYTE)

RST PD Select PIOW <PIO Output data> <invalid data byte> FF loop

16 of 18

DS2413: 1-Wire Dual Channel Addressable Switch

PIO ACCESS READ EXAMPLE

Read the state of the PIOs 3 times. With only a single DS2413 connected to the bus master, the communication looks like this:

MASTER MODE DATA (LSB FIRST) COMMENTS

TX (Reset) Reset pulse RX (Presence) Presence pulse TX CCh Issue “Skip ROM” command TX F5h Issue “PIO Access Read” command RX <3 data bytes> Read 3 PIO samples TX (Reset) Reset pulse RX (Presence) Presence pulse

PIO ACCESS WRITE EXAMPLE

Set both PIOs to 0 and then set PIOA to 1. Both PIOs are pulled high to V With only a single DS2413 connected to the bus master, the communication looks like this:

MASTER MODE DATA (LSB FIRST) COMMENTS

TX (Reset) Reset pulse RX (Presence) Presence pulse TX CCh Issue “Skip ROM” command TX 5Ah Issue “PIO Access Write” command TX FCh Write new PIO output state TX 03h Write inverted new PIO output state RX AAh Read confirmation byte RX F0h Read new PIO pin status TX FDh Write new PIO output state TX 02h Write inverted new PIO output state RX AAh Read confirmation byte RX C3h Read new PIO pin status TX (Reset) Reset pulse RX (Presence) Presence pulse

Note: Usually, the PIO pin state and PIO Output Latch State are the same. To read from a PIO, the PIO Output Latch must be 1. If the PIO pin is then pulled low by a switch or external circuitry, the output latch state and pin state are different.

or V

by a resistor.

PUP

PACKAGE INFORMATION

For the latest package outline information, go to www.maxim-ic.com/packages. Note that a “+”, “#”, or “-“ in the package code indicates RoHS status only. Package drawings may show a different suffix character, but the drawing pertains to the package regardless of RoHS status.

PACKAGE TYPE PACKAGE CODE DOCUMENT NO. LAND PATTERN

6 TSOC D6+1 21-0382 90-0321

6 TDFN T633+2 21-0137 90-0058

17 of 18

REVISION HISTORY

REVISION

DATE

 Remove epsilon from the tW1L spec in the EC table.  Apply EC table note 17 also to tWOL.  Add to EC table notes 17 and 18 the reference to Figure 12 and the text

"The actual maximum duration...."

11/07

11/08

07/10

 Show epsilon also in the write zero time slot graphic.

 Add note that the VTH and VTL maximum spec values apply at V

and V

 Added 3mm x 3mm x 0.8mm TDFN package.  LF update, delete standard versions (with lead) from ordering info.  Added Package Information Table.  Added “TDFN Packages Available” within the Features section.  Added new TDFN part number “DS2413Q+T&R,” and information to the

Ordering Information table.

 Removed the note to “Contact factory for availability of the TDFN package”

from the Ordering Information table.

 Changed soldering temperature from JEDEC reference to explicit values.  Added DS2482-related application hints to EC table, Note 2.  Removed reference to the DS2490.  Added land pattern reference.

are GBD, not tested).

DESCRIPTION

DS2413: 1-Wire Dual Channel Addressable Switch

PAGES

CHANGED

1, 3, 4, 14,

max (VTH

PUP

17, 18

2–3, 17

18 of 18

Maxim/Dallas Semiconductor cannot assume responsibility for use of any circuitry other than circuitry entirely embodied in a Maxim/Dallas Semiconductor product.

No circuit patent licenses are implied. Maxim/Dallas Semiconductor reserves the right to change the circuitry and specifications without notice at any time.

Maxim Integrated Products, 120 San Gabriel Drive, Sunnyvale, CA 94086 408-737-7600

MAXIM is a registered trademark of Maxim Integrated Products, Inc. DALLAS is a registered trademark of Dallas Semiconductor Corporation.

MAXIM DS2413 User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Figure 13. Noise Suppression Scheme