Datasheet

DS3930
Hex Nonvolatile Potentiometer with
I/O and Memory
____________________________________________________________________ 11
Applications Information
Power Supply Decoupling
To achieve the best results when using the DS3930,
decouple the power supply with a 0.1µF high-quality,
ceramic, surface-mount capacitor. Surface-mount com-
ponents minimize lead inductance, which improves
performance, and ceramic capacitors tend to have
adequate high-frequency response for decoupling
applications. The capacitor should be placed as close
as possible to the V
CC
and GND pins.
SDA
SCL
t
HD:STA
t
LOW
t
HIGH
t
R
t
F
t
BUF
t
HD:DAT
t
SU:DAT
REPEATED
START
t
SU:STA
t
HD:STA
t
SU:STO
t
SP
STOP START
Figure 5. 2-Wire AC Characteristics
SLAVE
ACK
10 0
1
R/WA0*A1*
SLAVE
ACK
A2*
MSB
LSB
DEVICE IDENTIFIER
DEVICE
ADDRESS
READ/
WRITE
MSB LSB
REGISTER ADDRESS
SLAVE
ACK
MSB LSB
b7 b6 b5 b4 b3 b2 b1 b0
SLAVE
ACK
STOP
*THE ADDRESS DETERMINED BY A0, A1, AND A2 MUST
MATCH THE ADDRESS SET BY THE ADDRESS PINS.
DATA
TYPICAL 2-WIRE WRITE TRANSACTION
EXAMPLE 2-WIRE TRANSACTIONS (WHEN A0, A1, AND A2 ARE ZERO)
A) SINGLE-BYTE WRITE
-WRITE TO POT 0 REGISTER
B) SINGLE-BYTE READ
-READ FROM POT 0 REGISTER
D) MULTIPLE BYTE WRITE
-2 BYTE WRITE TO EEPROM
E) MULTIPLE BYTE READ
-2 BYTE READ FROM EEPROM
START
START
START
START
START
A0h
A0h
A0h
A0h
SLAVE
ACK
SLAVE
ACK
SLAVE
ACK
SLAVE
ACK
F0h
F0h
00h
00h
SLAVE
ACK
SLAVE
ACK
SLAVE
ACK
SLAVE
ACK
DATA
SLAVE
ACK
STOP
POT SETTING10100000
10100000
10100000
10100000 10100001
REPEATED
START
SLAVE
ACK
MASTER
ACK
DATA
MASTER
NACK
STOP
DATA
A1h
b7 b6 b5 b4 b3 b2 b1 b0
11110000
C) SINGLE-BYTE WRITE
-SET I/O
0
PIN TO A "1"
START
A0h
SLAVE
ACK
F6h
SLAVE
ACK
DATA
SLAVE
ACK
STOP
XXX0XXX110100000
11110110
11110000
00000000
00000000
REPEATED
START
DATA
POT SETTING
MASTER
NACK
STOP
SLAVE
ACK
10100001
A1h
STOP
SLAVE
ACK
DATA
SLAVE
ACK
DATA
Figure 6. Example 2-Wire Transactions