CMOS 2-WIRE SERIAL EEPROM

S-24C01A/02A/04A

Seiko Instruments Inc.

9

6. Write

6.1 Byte Write

When the EEPROM receives a 7-bit length device address and a 1-bit read/write instruction code

"0," following the start condition signal, it outputs the acknowledgment signal. Next, when the

EEPROM receives an 8-bit length word address, it outputs the acknowledgment signal.

After the EEPROM receives 8-bit write data and outputs the acknowledgment signal, it receives the

stop condition signal. Next, the EEPROM at the specified memory address starts to rewrite.

When the EEPROM is rewriting, all operations are prohibited and the acknowledgment signal is not

output.

6.2 Page Write

Up to 8 bytes per page can be written in the S-24C01A and S-24C02A.

Up to 16 bytes per page can be written in the S-24C04A.

Basic data transmission procedures are the same as those in the "Byte Write." However, when the

EEPROM receives 8-bit write data which corresponds to the page size, the page can be written.

When the EEPROM receives a 7-bit length device address and a 1-bit read/write instruction code

"0," following the start condition signal, it outputs the acknowledgment signal. When the EEPROM

receives an 8-bit length word address, it outputs the acknowledgment signal.

After the EEPROM receives 8-bit write data and outputs the acknowledgment signal, it receives 8-

bit write data corresponding to the next word address, and outputs the acknowledgment signal. The

EEPROM repeats reception of 8-bit write data and output of the acknowledgment signal in

succession. It is capable of receiving write data corresponding to the maximum page size.

When the EEPROM receives the stop condition signal, it starts to rewrite, corresponding to the size

of the page, on which write data, starting from the specified memory address, is received.

Figure 10 Byte Write

S

T

A

R

T

1 0 1 0

W

R

I

T

E

S

T

O

P

DEVICE

ADDRES

WORD ADDRESS

DATA

R

/

W

M

S

B

SDA

ADR INC (ADDRESS INCREMENT)

A2 A1 A0

W7W6W5W4W3W2W1W0

D7 D6 D5 D4 D3 D2 D1 D0

A

C

K

L

S

B

A

C

K

A

C

K

0

W7 is optional in the S-24C01A.

A0 is P0 in the S-24C04A.