ds2431pt-r Maxim Integrated Products, Inc., ds2431pt-r Datasheet - Page 14

• Manufacturer Part Number: ds2431pt-r
• Description: Ds2431 1024-bit 1-wire Eeprom
• Manufacturer: Maxim Integrated Products, Inc.

Figure 8. Hardware Configuration
TRANSACTION SEQUENCE
The protocol for accessing the DS2431 through the 1-Wire port is as follows:
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 DS2431 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
DS2431 supports. All ROM function commands are 8 bits long. A list of these commands follows (refer to the flow
chart in Figure 9).
READ ROM [33h]
This command allows the bus master to read the DS2431’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
DS2431 on a multidrop bus. Only the DS2431 that exactly matches the 64-bit ROM sequence responds to the
following memory function command. All other slaves wait for a reset pulse. This command can be used with a
single or multiple devices on the bus.
Initialization
ROM Function Command
Memory Function Command
Transaction/Data
RX
TX
BUS MASTER
Open Drain
Port Pin
V
PUP
R
RX = RECEIVE
TX = TRANSMIT
PUP
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DATA
DS2431: 1024-Bit, 1-Wire EEPROM
DS2431 1-Wire PORT
I
L
100 Ω
MOSFET
RX
TX