at24c128b ATMEL Corporation, at24c128b Datasheet - Page 6

• Manufacturer Part Number: at24c128b
• Description: Two-wire Serial Eeprom 128k 16,384 X 8
• Manufacturer: ATMEL Corporation

6. Device Operation
6
AT24C128B
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
Data changes during SCL high periods will indicate a start or stop condition as defined below.
Figure 6-1.
START CONDITION: A high-to-low transition of SDA with SCL high is a start condition that must
precede any other command (see
Figure 6-2.
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
ure
ACKNOWLEDGE: All addresses and data words are serially transmitted to and from the
EEPROM in 8-bit words. The EEPROM sends a “0” during the ninth clock cycle to acknowledge
that it has received each word.
STANDBY MODE: The AT24C128B features a low-power standby mode that is enabled upon
power-up and 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, any 2-wire
part can be protocol reset by following these steps: (a) Create a start bit condition, (b) clock 9
6-2).
SDA
SCL
SDA
SCL
Data Validity
Start and Stop Definition
START
DATA STABLE
Figure
6-2).
CHANGE
DATA
DATA STABLE
STOP
5296A–SEEPR–1/08
Figure
6-1).
Fig-