R1EX24512BSAS0I/R1EX24512BTAS0I

R10DS0026EJ0400 Rev.4.00

Page 10 of 17

Sep, 20, 2013

Write Operations

(WP=Low)

Byte Write: (Write operation during WP=Low status)

A write operation requires an 8-bit device address word with R/W = “0”. Then the EEPROM sends acknowledgment

"0" at the ninth clock cycle. After these, the EEPROMs receive 2 sequence 8-bit memory address words. Upon receipt

of this memory address, the EEPROM outputs acknowledgment "0" and receives a following 8-bit write data. After

receipt of write data, the EEPROM outputs acknowledgment "0". If the EEPROM receives a stop condition, the

EEPROM enters an internally-timed write cycle and terminates receipt of SCL, SDA inputs until completion of the

write cycle. The EEPROM returns to a standby mode after completion of the write cycle.

Byte Write Operation

Device

address

1st Memory

address (n)

2nd Memory

address (n)

Write data (n)

512k

10 10

W

Stop

Start

ACK

ACK

ACK

R/W

WP

ACK

Page Write:

The EEPROM is capable of the page write operation which allows any number of bytes up to 128 bytes to be written in

a single write cycle. The page write is the same sequence as the byte write except for inputting the more write data.

The page write is initiated by a start condition, device address word, memory address(n) and write data (Dn) with every

ninth bit acknowledgment. The EEPROM enters the page write operation if the EEPROM receives more write data

(Dn+1) instead of receiving a stop condition. The a0 to a6 address bits are automatically incremented upon receiving

write data (Dn+1). The EEPROM can continue to receive write data up to 128 bytes. If the a0 to a6 address bits

reaches the last address of the page, the a0 to a6 address bits will roll over to the first address of the same page and

previous write data will be overwritten. Upon receiving a stop condition, the EEPROM stops receiving write data and

enters internally-timed write cycle.

Page Write Operation

Device

address

1st Memory

address (n)

2nd Memory

address (n)

Write data (n+m)

Write data (n)

512k

10 10

W

Stop

Start

ACK

ACK

ACK

ACK

ACK

R/W

WP