Rainbow Electronics DS1682 - Manual (Page 8)

DS1682
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2-WIRE SERIAL DATA BUS
The DS1682 supports a bidirectional, 2-wire bus and data-transmission protocol. A device that sends data
onto the bus is defined as a transmitter and a device receiving data, a receiver. The device that controls
the message is called a master, and the devices controlled by the master are slaves. The bus must be
controlled by a master device that generates the serial clock (SCL), controls the bus access, and generates
the START and STOP conditions. The DS1682 operates as a slave on the 2-wire bus. Connections to the
bus are made through the open-drain I/O lines SDA and SCL.
The following bus protocol has been defined (Figure 4):
Data transfer can be initiated only when the bus is not busy.
During data transfer, the data line must remain stable whenever the clock line is HIGH. Changes in
the data line while the clock line is high are interpreted as control signals.
Figure 4. TIMING DIAGRAM: DATA TRANSFER ON 2-WIRE SERIAL BUS