Low-Voltage SPI/3-Wire RTCs with
Trickle Charger
DS1390/DS1391/DS1392/DS1393
CS
SCLK
DIN
WRITE
ADDRESS
BYTE
DATA BYTE 0
DATA BYTE 1
DATA BYTE N
DIN
ADDRESS
BYTE
READ
DOUT
HIGH-IMPEDANCE
DATA
BYTE 0
DATA
BYTE 1
DATA
BYTE N
Figure 13. SPI Multiple-Byte Burst Transfer
CE
SCLK
I/O
A0
A1
A2
A3
A4
A5
A6
W/R
D0
D1
D2
D3
D4
D5
D6
D7
Figure 14. 3-Wire Single-Byte Read
CE
SCLK
I/O
A0
A1
A2
A3
A4
A5
A6
W/R
D0
D1
D2
D3
D4
D5
D6
D7
Figure 15. 3-Wire Single-Byte Write
20
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