X24645PI datasheet(3/18 Pages) XICOR

3 / 18 page

X24645

Figure 1. Data Validity

Figure 2. Definition of Start and Stop

DEVICE OPERATION

The X24645 supports a bidirectional bus oriented pro-

tocol. 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 pro-

vide the clock for both transmit and receive operations.

Therefore, the X24645 will be considered a slave in all

applications.

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 X24645 continuously monitors the SDA and

SCL lines for the start condition and will not respond to

any command until this condition has been met.

SCL

SDA

DATA STABLE

DATA

CHANGE

2783 ILL F04

SCL

SDA

START BIT

STOP BIT

2783 ILL F05

Notes: (5) Typical values are for TA = 25°C and nominal supply voltage (5V)

(6) tWR is the minimum cycle time from the system perspective when polling techniques are not used. It is the maximum time the

device requires to perform the internal write operation.

X24645PI Datasheet(PDF) 3 Page - Xicor Inc.