SLx 24C164/P

Semiconductor Group

11

1998-07-27

5

Write Operations

Changing of the EEPROM data is initiated by the master with the command byte CSW.

Depending on the state of the Write Protection pin WP and of the Protection Bits (refer

to chapter 7 Page Protection Mode

(Page Write) are modified in one programming procedure.

5.1

Byte Write

Figure 7

Byte Write Sequence

The erase/write cycle is finished latest after 8 ms. Acknowledge polling may be used for

speed enhancement in order to indicate the end of the erase/write cycle (refer to

chapter 5.3 Acknowledge Polling).

Address Setting

After a START condition the master transmits the Chip Select

Write byte CSW. The EEPROM acknowledges the CSW byte

during the ninth clock cycle. The following byte with the

EEPROM address (A0 to A7) is loaded into the address

counter of the EEPROM and acknowledged by the EEPROM.

Transmission of Data

Finally the master transmits the data byte which is also

acknowledged by the EEPROM into the internal buffer.

Programming Cycle

Then the master applies a STOP condition which starts the

internal programming procedure. The data bytes are written in

the memory location addressed in the EEA byte (A0 to A7)

and the CSW byte (A8 to A10). The programming procedure

consists of an internally timed erase/write cycle. In the first

step, the selected byte is erased to “1”. With the next internal

step, the addressed byte is written according to the contents

of the buffer.

Command Byte

CSW

S

P

C

K

A

C

K

A

S

T

A

R

T

T

P

O

S

EEPROM Address

EEA

Data Byte

Bus Activity

Master

SDA Line

Bus Activity

EEPROM

IED02129

C

K

A

0