S-24C01A Seiko Instruments Inc, S-24C01A Datasheet - Page 11

• Manufacturer Part Number: S-24C01A
• Description: CMOS 2-WIRE SERIAL EEPROM
• Manufacturer: Seiko Instruments Inc

Rev. 2.2
7.
Read
7.1 Current Address Read
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reading. The memory address is stored as long as the power voltage is more than the retention
voltage V
Accordingly, when the master device recognizes the position of the address pointer inside the
EEPROM, data can be read from the memory address of the current address pointer without
assigning a word address. This is called "Current Address Read."
address.
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. However, in the S-
24C04A, page address P0 becomes invalid, and the memory address of the current address pointer
becomes valid.
Next, 8-bit length data at an "n" address is output from the EEPROM, in synchronization with the
SCL clock.
The address counter is incremented at the falling edge of the SCL clock by which the 8th bit of data
is output, and the address counter goes to address n+1.
signal to finish reading.
The memory address counter inside the EEPROM is automatically incremented for every falling
edge of the SCL clock by which the 8th bit of data is output during the time of reading. During the
time of writing, upper bits of the memory address (upper 5 bits of the word address in the S-24C01A
and S-24C02A; upper 4 bits of the word address and page address P0 in the S-24C04A) are left
unchanged and are not incremented.
The EEPROM is capable of storing the last accessed memory address during both writing and
"Current Address Read" is explained for when the address counter inside the EEPROM is an "n"
The master device does not output the acknowledgment signal and transmits the stop condition
For recognition of the address pointer inside the EEPROM, take into consideration the following:
AH
.
SDA LINE
S
A
R
T
T
Figure 12 Current Address Read
M
S
B
1 0 1 0
ADDRESS
DEVICE
Seiko Instruments Inc.
(A0 is P0 in the S-24C04A)
A2 A1 A0
L
S
B
W
R
1
/
R
E
A
D
A
C
K
D7 D6 D5 D4 D3 D2 D1 D0
Master Device
NO ACK from
DATA
CMOS 2-WIRE SERIAL EEPROM
ADR INC
O
S
T
P
S-24C01A/02A/04A
11