X24320
Clock and Data Conventions
Data states on the SDA line can change only during
SCL LOW. SDA state changes during SCL HIGH are
reserved for indicating start and stop conditions. Refer to
Figures 1 and 2.
Start Condition
All commands are preceded by the start condition,
which is a HIGH to LOW transition of SDA when SCL
is HIGH. The device continuously monitors the SDA and
SCL lines for the start condition and will not
respond to any command until this condition has been met
.
DEVICE OPERATION
The device supports a bidirectional bus oriented
protocol. The protocol defines any device that sends
data onto the bus as a transmitter, and the receiving device
as the receiver. The device controlling the
transfer is a master and the device being controlled is the
slave. The master will always initiate data transfers
and provide the clock for both transmit and receive
operations. Therefore, the device will be
considered a slave in all applications.
Figure 1. Data Validity
SCL
SDA
DATA STABLE
DATA
CHANGE
7035 FM 03
Figure 2. Definition of Start and Stop
SCL
SDA
START BIT
STOP BIT
7035 FM 04
3
ICMIC [ IC MICROSYSTEMS ]
