x9522v20iz-bt1 Intersil Corporation, x9522v20iz-bt1 Datasheet - Page 5

• Manufacturer Part Number: x9522v20iz-bt1
• Description: Triple Dcp, Dual Voltage Monitors
• Manufacturer: Intersil Corporation

DEVICE INTERNAL ADDRESSING
Addressing Protocol Overview
The user addressable internal components of the X9522
can be split up into two main parts:
—Three Digitally Controlled Potentiometers (DCPs)
—Control and Status (CONSTAT) Register
Depending upon the operation to be performed on
each of these individual parts, a 1, 2 or 3 Byte proto-
col is used. All operations however must begin with
the Slave Address Byte being issued on the SDA pin.
The Slave address selects the part of the X9522 to
be addressed, and specifies if a Read or Write opera-
tion is to be performed.
It should be noted that in order to perform a write opera-
tion to a DCP, the Write Enable Latch (WEL) bit must first
be set.
Slave Address Byte
Following a START condition, the master must output a
Slave Address Byte (Refer to Figure 4.). This byte con-
sists of three parts:
—The Device Type Identifier which consists of the most
significant four bits of the Slave Address (SA7 - SA4).
The Device Type Identifier must always be set to 1010
in order to select the X9522.
Data Output
Data Output
Transmitter
Receiver
Master
Master
from
from
from
from
SCL
SCL
Start
5
Figure 3.
Acknowledge Response From Receiver
1
X9522
—The next three bits (SA3 - SA1) are the Internal Device
—The Least Significant Bit of the Slave Address (SA0)
Address bits. Setting these bits to 111 internally
selects the DCP structures in the X9522. The CON-
STAT Register may be selected using the Internal
Device Address 010.All other bit combinations are
RESERVED.
Byte is the R/W bit. This bit defines the operation to be
performed on the device being addressed (as defined
in the bits SA3 - SA1). When the R/W bit is “1”, then a
READ operation is selected. A “0” selects a WRITE
operation (Refer to Figure 4.)
Figure 4.
SA7
1 0 1 0
Internal Address
DEVICE TYPE
(SA3 - SA1)
IDENTIFIER
8
Bit SA0
Others
SA6
010
111
0
1
SA5
Slave Address Format
Acknowledge
SA4
9
SA3
Internally Addressed
CONSTAT Register
INTERNAL
ADDRESS
DEVICE
RESERVED
SA2
Operation
Device
WRITE
READ
DCP
SA1
READ /
WRITE
R/W
SA0
January 3, 2006
FN8208.1