Datasheet

DS2482-100: Single-Channel 1-Wire Master
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A slave device that is ready to communicate acknowledges at least its slave address. However, some time later the
slave may refuse to accept data, e.g., because of an invalid command code or parameter. In this case the slave
device does not acknowledge any of the bytes that it refuses and leaves SDA HIGH. In either case, after a slave
has failed to acknowledge, the master first needs to generate a repeated START condition or a STOP condition
followed by a START condition to begin a new data transfer.
Not Acknowledged by Master: At some time when receiving data, the master must signal an end of data to the
slave device. To achieve this, the master does not acknowledge the last byte that it has received from the slave. In
response, the slave releases SDA, allowing the master to generate the STOP condition.
Writing to the DS2482-100
To write to the DS2482-100, the master must access the device in write mode, i.e., the slave address must be sent
with the direction bit set to 0. The next byte to be sent is a command code, which, depending on the command,
may be followed by a command parameter. The DS2482-100 acknowledges valid command codes and
expected/valid command parameters. Additional bytes or invalid command parameters are never acknowledged.
Reading from the DS2482-100
To read from the DS2482-100, the master must access the device in read mode, i.e., the slave address must be
sent with the direction bit set to 1. The read pointer determines the register that the master will read from. The
master may continue reading the same register over and over again, without having to re-address the device, e.g.,
to watch the 1WB changing from 1 to 0. To read from a different register, the master must issue the Set Read
Pointer command and then access the DS2482-100 again in read mode.
I²C Communication—Legend
SYMBOL DESCRIPTION SYMBOL DESCRIPTION
S START Condition DRST Command "Device Reset", F0h
AD, 0 Select DS2482-100 for Write Access WCFG Command "Write Configuration", D2h
AD, 1 Select DS2482-100 for Read Access SRP Command "Set Read Pointer", E1h
Sr Repeated START Condition 1WRS Command "1-Wire Reset", B4h
P STOP Condition 1WWB Command "1-Wire Write Byte", A5h
A Acknowledged 1WRB Command "1-Wire Read Byte", 96h
A\ Not Acknowledged 1WSB Command "1-Wire Single Bit", 87h
(Idle) Bus Not Busy 1WT Command "1-Wire Triplet", 78h
<byte> Transfer of One Byte
Data Direction Codes
Master-to-Slave Slave-to-Master