ISL22326 Intersil Corporation, ISL22326 Datasheet - Page 11

• Manufacturer Part Number: ISL22326
• Manufacturer: Intersil Corporation

An ACK, Acknowledge, is a software convention used to
indicate a successful data transfer. The transmitting device,
either master or slave, releases the SDA bus after
transmitting eight bits. During the ninth clock cycle, the
receiver pulls the SDA line LOW to acknowledge the
reception of the eight bits of data (See Figure 17).
The ISL22326 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
ISL22326 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.
SDA OUTPUT FROM
SDA OUTPUT FROM
TRANSMITTER
SCL FROM
RECEIVER
SDA
SCL
MASTER
SIGNALS FROM
SIGNAL AT SDA
SIGNALS FROM
THE MASTER
THE SLAVE
11
START
FIGURE 16. VALID DATA CHANGES, START AND STOP CONDITIONS
START
FIGURE 17. ACKNOWLEDGE RESPONSE FROM RECEIVER
HIGH IMPEDANCE
S
A
R
T
T
FIGURE 18. BYTE WRITE SEQUENCE
1
IDENTIFICATION
0
1
1
BYTE
0
A2
STABLE
DATA
A1
ISL22326
A0
WRITE
0
A
C
K
CHANGE
DATA
0 0 0 0
ADDRESS
A valid Identification Byte contains 1010 as the four MSBs,
and the following three bits matching the logic values
present at pins A2, A1, and A0. The LSB is the Read/Write
bit. Its value is “1” for a Read operation, and “0” for a Write
operation (See Table 3).
(MSB)
BYTE
0
1
STABLE
DATA
TABLE 3. IDENTIFICATION BYTE FORMAT
0
A
C
K
8
Logic values at pins A2, A1, and A0 respectively
1
DATA
BYTE
0
HIGH IMPEDANCE
STOP
ACK
9
A2
A
C
K
S
T
O
P
A1
A0
July 17, 2006
FN6176.0
(LSB)
R/W