ISL28022_15 Datasheet, PDF (21/32 Pages) Intersil Corporation – Precision Digital Power Monitor

ISL28022
Device Addressing
Following a start condition, the master must output a slave address
byte. The 7 MSBs are the device identifiers. The A0 and A1 pins
control the bus address (these bits are shown in Table 22). There
are 16 possible combinations depending on the A0/A1 connections.
The last bit of the slave address byte defines a read or write
operation to be performed. When this R/W bit is a “1”, a read
operation is selected. A “0” selects a write operation (refer to
Figure 29).
After loading the entire slave address byte from the SDA bus, the
ISL28022 compares the loaded value to the internal slave
address. Upon a correct compare, the device outputs an
acknowledge on the SDA line.
Following the slave byte is a one byte word address. The word
address is either supplied by the master device or obtained from
an internal counter. On power-up, the internal address counter is
set to address 00h, so a current address read starts at address
00h. When required, as part of a random read, the master must
supply the one word address byte, as shown in Figure 30.
In a random read operation, the slave byte in the “dummy write”
portion must match the slave byte in the “read” section. For a
random read of the registers, the slave byte must be “100nnnnx”
in both places.
TABLE 22. I²C SLAVE ADDRESSES
A1
A0
SLAVE ADDRESS
GND
GND
1000 000
GND
VCC
1000 001
GND
SDA
1000 010
GND
SCL
1000 011
VCC
GND
1000 100
VCC
VCC
1000 101
VCC
SDA
1000 110
VCC
SCL
1000 111
SDA
GND
1001 000
SDA
VCC
1001 001
SDA
SDA
1001 010
SDA
SCL
1001 011
SCL
GND
1001 100
SCL
VCC
1001 101
SCL
SDA
1001 110
SCL
SCL
1001 111
Broadcast Address
0111 111
SIGNALS
FROM THE
MASTER
S
T _{IDENTIFICATION}
A
R
T
BYTE WITH
R/W = 0
ADDRESS
BYTE
S
T
A
R
T
IDENTIFICATION
BYTE WITH
R/W = 1
A
C
K
SIGNAL AT
SDA
100nnnn0
A
SIGNALS FROM
C
THE SLAVE
K
100nnnn1
A
A
C
K
C
K
FIRST READ
DATA BYTE
FIGURE 30. READ SEQUENCE (SLAVE ADDRESS SHOWN AS nnnn)
S
T
O
P
SECOND READ
DATA BYTE
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FN8386.7
October 2, 2015