6

5134E–SEEPR–3/08

AT24HC02B

5.

Device Operation

CLOCK and DATA TRANSITIONS: The SDA pin is normally pulled high with an external

device. Data on the SDA pin may change only during SCL low time periods (see Figure 5-1).

Data changes during SCL high periods will indicate a start or stop condition as defined below.

Figure 5-1.

Data Validity

START CONDITION: A high-to-low transition of SDA with SCL high is a start condition that must

precede any other command (see Figure 5-2).

Figure 5-2.

Start and Stop Definition

STOP CONDITION: A low-to-high transition of SDA with SCL high is a stop condition. After a

read sequence, the stop command will place the EEPROM in a standby power mode (see Fig-

ure 5-2).

ACKNOWLEDGE: All addresses and data words are serially transmitted to and from the

word. This happens during the ninth clock cycle.

STANDBY MODE: The AT24HC02B features a low-power standby mode that is enabled: (a)

upon power-up and (b) after the receipt of the Stop bit and the completion of any internal

operations.

SDA

SCL

DATA STABLE

DATA STABLE

DATA

CHANGE

SDA

SCL

START

STOP