s-24c02afja-11-s Seiko Instruments Inc., s-24c02afja-11-s Datasheet - Page 12

• Manufacturer Part Number: s-24c02afja-11-s
• Description: Cmos 2-wire Serial Eeprom
• Manufacturer: Seiko Instruments Inc.

CMOS 2-WIRED SERIAL EEPROM
S-24C01A/02A/04A
12
SDA LINE
7.2 Random Read
Random read is a mode used when the data is read from arbitrary memory addresses.
To load a memory address into the address counter inside the EEPROM, first perform a dummy write
according to the following procedures:
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, the EEPROM receives an 8-bit length word address and outputs the acknowledgment signal. Last,
the memory address is loaded into the address counter of the EEPROM.
the EEPROM receives the write data during byte or page writing. However, data reception is not
performed during dummy write.
The memory address is loaded into the memory address counter inside the EEPROM during dummy write.
After that, the master device can read the data starting from the arbitrary memory address by transmitting
a new start condition signal and performing the same operation as that in the "Current Read."
That is, when the EEPROM receives a 7-bit length device address and a 1-bit read/write instruction code
"1," following the start condition signal, it outputs the acknowledgment signal.
Next, 8-bit length data is output from the EEPROM, in synchronization with the SCL clock. The master
device does not output an acknowledgment signal and transmits the stop condition signal to finish reading.
S
T
A
R
T
M
S
B
1
0 1 0
ADDRESS
DEVICE
A2 A1 A0
DUMMY WRITE
S
B
L
W
W
R
T
E
R
0
I
/
A
C
K
W7W6W5W4W3W2W1W0
WORD
W7 is optional in the S-24C01A.
A0 is P0 in the S-24C04A.
Figure 13 Random Read
ADDRESS (n)
Seiko Instruments Inc.
A
C
K
S
A
R
T
T
1
0 1 0 A2 A1 A0 1
ADDRESS
DEVICE
R
E
A
D
A
C
K
D7 D6 D5 D4 D3 D2 D1 D0
Master Device
NO ACK from
DATA (n)
Rev. 2.2
ADR INC
S
T
O
P
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