ISL23325 Datasheet, PDF (16/20 Pages) Intersil Corporation – Dual, 256-Tap, Low Voltage Digitally Controlled Potentiometer (XDCP™)

ISL23325
SCL FROM
MASTER
1
SDA OUTPUT FROM
TRANSMITTER
8
9
HIGH IMPEDANCE
SDA OUTPUT FROM
RECEIVER
HIGH IMPEDANCE
START
FIGURE 28. ACKNOWLEDGE RESPONSE FROM RECEIVER
ACK
SIGNALS FROM
THE MASTER
S
WRITE
T
A _{IDENTIFICATION}
R
BYTE
T
ADDRESS
BYTE
S
DATA
T
BYTE
O
P
SIGNAL AT SDA
1 0 1 0 A2A1 A0 0 0 0 0
SIGNALS FROM
THE SLAVE
A
A
A
C
C
C
K
K
K
FIGURE 29. BYTE WRITE SEQUENCE
S
S
READ
SIGNALS
FROM THE
MASTER
T
A IDENTIFICATION
R
BYTE WITH
T
R/W = 0
ADDRESS
BYTE
T
A IDENTIFICATION
R _{BYTE WITH}
T
R/W = 1
A
C
K
SIGNAL AT SDA 1 0 1 0 A2A1 A0 0 0 0 0
A
SIGNALS FROM
C
THE SLAVE
K
1 0 1 0 A2A1 A0 1
A
A
C
C
K
K
FIGURE 30. READ SEQUENCE
FIRST READ
DATA BYTE
A
C
K
S
AT
CO
KP
LAST READ
DATA BYTE
Write Operation
A Write operation requires a START condition, followed by a valid
Identification Byte, a valid Address Byte, a Data Byte, and a STOP
condition. After each of the three bytes, the ISL23325 responds
with an ACK. The data is transferred from I²C block to the
corresponding register at the 9th clock of the data byte and the
device enters its standby state (see Figures 28 and 29).
It is possible to perform a sequential Write to all DCP channels
via a single Write operation. The command is initiated by sending
an additional Data Byte after the first Data byte instead of
sending a STOP condition.
Read Operation
A Read operation consists of a three byte instruction followed by
one or more Data Bytes (see Figure 30). The master initiates the
operation issuing the following sequence: a START, the
Identification byte with the R/W bit set to “0”, an Address Byte, a
second START, and a second Identification byte with the R/W bit
set to “1”. After each of the three bytes, the ISL23325 responds
with an ACK; then the ISL23325 transmits Data Byte. The master
terminates the read operation issuing a NACK (ACK) and a STOP
condition following the last bit of the last Data Byte (see
Figure 30).
16
FN7870.0
June 21, 2011