DS1961S-F3 Maxim Integrated Products, DS1961S-F3 Datasheet - Page 26

• Manufacturer Part Number: DS1961S-F3
• Description: IBUTTON EEPROM 1KBit SHA-1 2CAN
• Manufacturer: Maxim Integrated Products
• Series: iButton®r

Specifications of DS1961S-F3

• Rohs Information: IButton RoHS Compliance Plan
• Memory Size: 128B
• Memory Type: EEPROM
• Lead Free Status / RoHS Status: Contains lead / RoHS non-compliant

Figure 8. HARDWARE CONFIGURATION
TRANSACTION SEQUENCE
The protocol for accessing the DS1961S through the 1-Wire port is as follows:
§ Initialization
§ ROM Function Command
§ Memory or SHA Function Command
§ Transaction/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 DS1961S is on the bus and is ready to
operate. For more details, see the 1-Wire Signaling section.
ROM FUNCTION COMMANDS
Once the bus master has detected a presence, it can issue one of the seven ROM function commands that
the DS1961S supports. All ROM function commands are eight bits long. A list of these commands
follows (see the flow chart in Figure 9):
Read ROM [33h]
This command allows the bus master to read the DS1961S’s 8-bit family code, unique 48-bit serial
number, and 8-bit CRC. This command should 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 read
by the master are invalid.
Match ROM [55h]
The match ROM command, followed by a 64-bit registration number, allows the bus master to address a
specific DS1961S on a multidrop bus. Only the DS1961S that exactly matches the 64-bit registration
number responds to the following memory function command. All other slaves wait for a reset pulse.
This command can be used with single or multiple devices on the bus.
RX
TX
BUS MASTER
OPEN-DRAIN
PORT PIN
V
R
PUP
RX = RECEIVE
TX = TRANSMIT
PU
26 of 36
5µA
(typ)
DATA
DS1961S 1-WIRE PORT
100 W
MOSFET
RX
TX