S-24C02D Datasheet, PDF (17/47 Pages) Seiko Instruments Inc – 2-WIRE SERIAL E2PROM

Rev.3.0_01_U
2-WIRE SERIAL E²PROM
S-24C02D/04D/08D16D
7. 4 Acknowledge polling
Acknowledge polling is used to know the completion of the write cycle in this IC.
After this IC receives a stop condition and once starts the write cycle, all operations are forbidden and no
response is made to the signal transmitted by the master device.
Accordingly the master device can recognize the completion of the write cycle in this IC by detecting a response
from the slave device after transmitting the start condition, the device address and the read / write instruction
code to this IC, namely to the slave devices.
That is, if this IC does not generate an acknowledge, the write cycle is in progress and if this IC generates an
acknowledge, the write cycle has been completed.
It is recommended to use the read instruction "1" as the read / write instruction code transmitted by the master
device.
Acknowledge polling during read
SDA
LINE
S
T
O
DATA
P
D2 D1 D0
S
T
A
R
T
R
E
A
D
DEVICE
ADDRESS
1
RN
/A
W
C
K
NO ACK from
S
T
A
R
T
R ^{Master Device}
E
A
D
DEVICE
ADDRESS
1
DATA
RA
/C
WK
S
T
O
P
S
T
A
R
T
DEVICE
ADDRESS
RA
/C
WK
t_WR
Acknowledge polling during write
SDA
LINE
S
T
O
DATA
P
D2 D1 D0
S
T
A
R
T
W
R
I
T
E
DEVICE
ADDRESS
0
R
/
W
N
A
C
K
S
T
A
R
T
W
R
I
T
E
DEVICE
ADDRESS
0
WORD
ADDRESS
RA
A
/C
C
WK
K
t_WR
Remark
Users are able to read data after acknowledge output in acknowledge polling during read.
Users are able to input word address and data after acknowledge output in acknowledge polling during write.
However, after that users input the write instruction, a start condition may not be input during data output. Input a
stop condition and the next instruction after data output and acknowledge output.
Figure 12 Usage Example of Acknowledge Polling
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