Datasheet

Section 17 EEPROM
Rev. 6.00 Mar. 24, 2006 Page 293 of 412
REJ09B0142-0600
17.4.7 Write Operations
There are two types write operations; byte write operation and page write operation. To initiate
the write operation, input 0 to R/W code following the slave address.
1. Byte Write
A write operation requires an 8-bit data of a 7-bit slave address with R/W code = "0". Then
the EEPROM sends acknowledgement "0" at the ninth bit. This enters the write mode. Then,
two bytes of the memory address are received from the MSB side in the order of upper and
lower. Upon receipt of one-byte memory address, the EEPROM sends acknowledgement "0"
and receives a following a one-byte write data. After receipt of write data, the EEPROM sends
acknowledgement "0". If the EEPROM receives a stop condition, the EEPROM enters an
internally controlled write cycle and terminates receipt of SCL and SDA inputs until
completion of the write cycle. The EEPROM returns to a standby mode after completion of
the write cycle.
The byte write operation is shown in figure 17.3.
R/W ACK
SCL
SDA
ACK ACKACK
112345678
A15 A8 A7 A0 D7 D0
9189 189 8
9
Start
condition
Upper memory
address
lower memory
address
Write DataSlave address
Stop
conditon
[Legend]
R/W: R/W code (0 is for a write and 1 is for a read)
ACK: acknowledge
Figure 17.3 Byte Write Operation
2. Page Write
This LSI is capable of the page write operation which allows any number of bytes up to 8
bytes to be written in a single write cycle. The write data is input in the same sequence as the
byte write in the order of a start condition, slave address + R/W code, memory address (n), and
write data (Dn) with every ninth bit acknowledgement "0" output. The EEPROM enters the
page write operation if the EEPROM receives more write data (Dn+1) is input instead of
receiving a stop condition after receiving the write data (Dn). LSB 3 bits (A2 to A0) in the
EEPROM address are automatically incremented to be the (n+1) address upon receiving write
data (Dn+1). Thus the write data can be received sequentially.