24C02 / 24C04 / 24C08 / 24C16
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 to Figure 1 on page 4). Data changes during SCL high periods
will indicate a start or stop condition as defined below.
START CONDITION: A high-to-low transition of SDA with SCL high is a start condition which must precede any other
command (see to Figure 2 on page 4).
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 Figure 2 on page 4).
ACKNOWLEDGE: All addresses and data words are serially transmitted to and from the EEPROM in 8-bit words. The
EEPROM sends a "0" to acknowledge that it has received each word. This happens during the ninth clock cycle.
STANDBY MODE: The 24C02/ 24C04/ 24C08/ 24C16 features a low-power standby mode which is enabled: (a)
upon power-up and (b) after the receipt of the STOP bit and the completion of any internal operations
MEMORY RESET: After an interruption in protocol, power loss or system reset, any two-wire part can be reset by
following these steps:
1. Clock up to 9 cycles.
2. Look for SDA high in each cycle while SCL is high.
3. Create a start condition.
Figure 1: Data Validity
SDA
SCL
DATA STABLE
DATA STABLE
DATA
CHANGE
Figure 2: Start and Stop Definition
SDA
SCL
START
STOP
BEIJING ESTEK ELECTRONICS CO.,LTD
4
ESTEK [ Estek Electronics Co. Ltd ]
