isl90842 Intersil Corporation, isl90842 Datasheet - Page 8

• Manufacturer Part Number: isl90842
• Description: Quad Digitally Controlled Potentiometers Xdcp?
• Manufacturer: Intersil Corporation

The ISL90842 responds with an ACK after recognition of a
START condition followed by a valid Identification Byte, and
once again after successful receipt of an Address Byte. The
ISL90842 also responds with an ACK after receiving a Data
Byte of a write operation. The master must respond with an
ACK after receiving a Data Byte of a read operation
A valid Identification Byte contains 01010 as the five MSBs,
and the following two bits matching the logic values present
at pins A1 and A0. The LSB is the Read/Write bit. Its value is
SDA OUTPUT FROM
SDA OUTPUT FROM
TRANSMITTER
SCL FROM
RECEIVER
SDA
SCL
MASTER
SIGNALS FROM
SIGNAL AT SDA
SIGNALS FROM
THE MASTER
THE ISL90842
8
START
FIGURE 9. VALID DATA CHANGES, START, AND STOP CONDITIONS
START
FIGURE 10. ACKNOWLEDGE RESPONSE FROM RECEIVER
HIGH IMPEDANCE
S
A
R
T
T
0
FIGURE 11. BYTE WRITE SEQUENCE
IDENTIFICATION
1
1
0
BYTE
1
STABLE
0
DATA
A1
ISL90842
A0
WRITE
0
A
C
K
CHANGE
DATA
0 0 0 0
ADDRESS
“1” for a Read operation, and “0” for a Write operation (See
Table 1).
(MSB)
BYTE
0 0 0 0
0
STABLE
DATA
TABLE 1. IDENTIFICATION BYTE FORMAT
1
A
C
K
8
Logic values at pins A1, and A0 respectively
0
DATA
BYTE
1
HIGH IMPEDANCE
STOP
ACK
9
0
A
C
K
S
T
O
P
A1
A0
January 16, 2006
FN8096.1
(LSB)
R/W