X24012
DEVICE OPERATION
Clock and Data Conventions
DatastatesontheSDAlinecanchangeonlyduringSCL
LOW. SDA state changes during SCL HIGH are re-
served for indicating start and stop conditions. Refer to
Figures 1 and 2.
The X24012 supports a bidirectional bus oriented proto-
col. 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. There-
fore, the X24012 will be considered a slave in all
applications.
Start Condition
All commands are preceded by the start condition,
which is a HIGH to LOW transition of SDA when SCL is
HIGH. The X24012 continuously monitors the SDA and
SCL lines for the start condition and will not respond to
any command until this condition has been met.
Figure 1. Data Validity
SCL
SDA
DATA STABLE
DATA
CHANGE
3847 FHD F05
Figure 2. Definition of Start and Stop
SCL
SDA
START BIT
STOP BIT
3847 FHD F06
3
XICOR [ XICOR INC. ]
