S-34C04A Datasheet, PDF (15/22 Pages) Seiko Instruments Inc – FOR DIMM SERIAL PRESENCE DETECT

Rev.1.0_01_U
2-WIRE SERIAL E²PROM FOR DIMM SERIAL PRESENCE DETECT
S-34C04A
1. 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 write
DATA
SS
TT
OA
PR
T
W
R
I
T
E
SDA
LINE
D2 D1 D0
DEVICE
SELECT CODE
0
RN
/A
W
C
K
t_WR
Acknowledge polling during read
DATA
SS
TT
OA
PR
T
R
E
A
D
SDA
LINE
D2 D1 D0
DEVICE
SELECT CODE
1
RN
/A
W
C
K
t_WR
S
T
A
R
T
W
R
I
T
E
DEVICE
SELECT CODE
0
WORD
ADDRESS
RA
A
/C
C
WK
K
NO ACK from
S
T
A
R
T
R ^{Master Device}
E
A
D
DEVICE
SELECTCODE
1
DATA
RA
/C
WK
SS
TT
OA
PR
T
DEVICE
SELECT CODE
RA
/C
WK
Remark
Users are able to input data after acknowledge output in acknowledge polling during write.
Users are able to read data after acknowledge output in acknowledge polling during read.
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 acknowledge output and data output.
Figure 11 Usage Example of Acknowledge Polling
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