Low-Voltage SPI/3-Wire RTCs with
Trickle Charger
DS1390/DS1391/DS1392/DS1393
CS
t
CC
SCLK
t
R
t
F
t
CL
t
CDH
DIN
t
DC
W/R
A6
t
CH
t
CDD
A0
t
CDZ
DOUT
D7
D0
WRITE ADDRESS BYTE
NOTE:
SCLK CAN BE EITHER POLARITY, SHOWN FOR CPOL = 1.
READ DATA BYTE
Figure 1. Timing Diagram鈥擲PI Read Transfer
CS
SCLK
t
CC
t
R
t
CL
t
F
t
CWH
t
CCH
DIN
t
DC
W/R
t
CDH
t
CH
A6
A0
D7
D0
WRITE ADDRESS BYTE
WRITE DATA BYTE
Figure 2. Timing Diagram鈥擲PI Write Transfer
4
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