Rainbow Electronics AT24C1024B - Manual (Page 6)

6
AT24C1024B [Preliminary]
5194D–SEEPR–5/07
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 4 on
page 7). 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 Figure 5 on page 7).
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 5 on page 7).
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 acknowl-
edge that it has received each word.
STANDBY MODE: The AT24C1024B 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.
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
cycles, (c) 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.
Figure 2. Bus Timing (SCL: Serial Clock, SDA: Serial Data I/O ® )
SCL
SDA
1 2 3 8 9
Start Bit Start Bit Stop Bit Dummy Clock Cycles