DS2411

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1-WIRE SIGNALING

The DS2411 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 0, Write 1, and Read

Data. Except for the presence pulse the bus master initiates all these signals. The DS2411 can

communicate at two different speeds: standard speed and Overdrive speed. If not explicitly set into the

Overdrive mode, the DS2411 will communicate at standard speed. While in Overdrive Mode the fast

timing applies to all waveforms.

The initialization sequence required to begin any communication with the DS2411 is shown in Figure 6.

A Reset Pulse followed by a Presence Pulse indicates the DS2411 is ready to receive data, given the

needs to be long enough for the slowest 1-Wire slave device to recognize it as a reset pulse. If the bus

remain in Overdrive Mode.

After the bus master has released the line it goes into receive mode (RX). Now, the 1-Wire bus is pulled

extended to minimum 480µs at standard speed and 48µs at Overdrive speed to accommodate other 1-

Wire devices.

Read/Write Time Slots

Data communication with the DS2411 takes place in time slots that carry a single bit each. Write time

slots transport data from bus master to slave. Read time-slots transfer data from slave to master. The

definitions of the write and read time slots are illustrated in Figure 7.

All communication begins with the master pulling the data line low. As the voltage on the 1-Wire line

data line will be sampled during a write time slot and how long data will be valid during a read time slot.

Master to Slave

the next time slot.