AD5245 Analog Devices, AD5245 Datasheet - Page 11

• Manufacturer Part Number: AD5245
• Description: 256-Position I2C Compatible Digital Potentiometer
• Manufacturer: Analog Devices

I
Table 5. Write Mode
Table 6. Read Mode
S = Start Condition
P = Stop Condition
A = Acknowledge
X = Don’t Care
W = Write
START BY
2
S
MASTER
S
C INTERFACE
SCL
SDA
0
0
SDA
SCL
1
1
Slave Address Byte
P
0
0
1
t
SLAVE ADDRESS BYTE
Slave Address Byte
0
1
1
START BY
MASTER
1
S
FRAME 1
1
1
0
SCL
t
SDA
2
0 AD0 W
1
1
1
1
0
t
0
3
Figure 38. Reading Data from a Previously Selected RDAC Register in Write Mode
0
1
AD0
AD0
SLAVE ADDRESS BYTE
t
8
0
A
t
8
R/W
FRAME 1
R
X
1
ACK BY
AD5245
t
9
Figure 36. I
9
1
RS SD
Figure 37
A
t
6
1
X
0
Instruction Byte
D7
2
RS
Rev. 0 | Page 11 of 16
C Interface Detailed Timing Diagram
AD0
. Writing to the RDAC Register
t
t
4
9
X
SD
INSTRUCTION BYTE
D6
R/W
X
ACK BY
AD5245
FRAME 2
X
9
D5
X
R = Read
RS = Reset wiper to Midscale 80
SD = Shutdown connects wiper to B terminal and open
circuits A terminal. It does not change contents of wiper
register.
D7, D6, D5, D4, D3, D2, D1, D0 = Data Bits
X
t
D7
1
7
Data Byte
D4
X
X
D6
X
D3
X
D5
RDAC REGISTER
A
X
D2
S
D4
FRAME 2
ACK BY
AD5245
t
D7 D6 D5 D4 D3 D2 D1 D0
5
9
D3
D1
D7
1
D2
t
D0
2
D6
D1
Data Byte
D5
A
H
D0
DATA BYTE
NO ACK
BY MASTER
D4
FRAME 3
9
P
D3
STOP BY
MASTER
D2
D1
D0
P
AD5245
ACK BY
AD5245
A
t
10
9
STOP BY
MASTER
P