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 (refer to “Data Validity” diagram). 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 (refer to “Start and Stop Definition” diagram).
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 (refer to “Start and Stop Definition” diagram).
ACKNOWLEDGE: All addresses and data words are serially transmitted to and from the EEPROM in 8-bit words.
The EEPROM sends a zero during the ninth clock cycle to acknowledge that it has received each word.
STANDBY MODE: The AT24C32D/64D features a low power standby mode which is enabled:
• Upon power-up
• After the receipt of the Stop bit and the completion of any internal operations.
SOFTWARE RESET: After an interruption in protocol, power loss or system reset, and 2-wire part can be protocol
reset by following these steps:
• Create a start bit condition
• Clock 9 cycles
• Create another start bit followed by stop bit condition as shown below.
The device is ready for next communication after above steps have been completed
