ADT7460 Analog Devices, Inc., ADT7460 Datasheet - Page 14

• Manufacturer Part Number: ADT7460
• Description: Dbcool? Remote Thermal Controller And Fan Controller
• Manufacturer: Analog Devices, Inc.

ADT7460
For the ADT
address pointer register for a subsequent single-byte read from
the same address. This is illustrated in Figure 21.
If it is required to read data from the register immediat
set
con ition immediately after the final ACK a
single-byte read without asserting an intermediate stop
con ition.
Wr te Byte
In t is operation, the master device s
one data byte to the slave device as follows:
1.
2.
3.
4.
5.
6.
7.
8.
This is illustrated i
Read Operations
The ADT7460 uses the following SMB
Rec ive Byte
This is useful when repeatedly reading a single register. Th
regis
operation, the master device receives a single byte from a slave
device as follows:
1.
2.
tin
i
h
d
d
e
ter address needs to
The master d
The master sends the 7-bit
write bit (low).
The addressed slave device asserts ACK on SDA.
The maste
The slave assert
The master sends a data byte.
The slave
The master asserts a stop condition on SDA to end the
transaction.
The master device asserts a start condition on SD
The master sends the 7-bit ave address followed by the
read bit (
g up the address, the master can assert a repeat st
Figure 21. Settin
S
1
7460, the send byte protocol is used to write to the
ADDRESS
high).
asserts ACK on SDA.
SLAVE
r sends the register address.
S
Figure
1
2
ADDRESS
evice asserts a start condition on SDA.
SLAVE
n Figure 22.
s ACK on SDA.
2
22. Single-Byte Write to a Register
g a Register Address for Subsequent Read
W
A
3
have been set up previously. In this
W A
REGISTER
ADDRESS
3
4
REGISTER
slave address followed by the
sl
ADDRESS
4
ends a command byte and
A
5
us read protocols.
DATA
A P
5 6
6
nd carry out a
A P
7 8
A.
art
ely after
e
Rev. C | Page 14 of 52
3.
4.
5.
6.
In the ADT7460, the receive byte protocol is used to read a
single byte of data from a register whose address has previously
been set by
Alert Response Address
Ale t response address (ARA) is a feature of SMBus devices tha
allow
mul
The
can be used as an SMBALERT . One or more outputs can be
conn
mas
occurs:
1.
2.
3.
4.
5.
r
tiple devices exist on the same bus.
ter. If a device’s
SMBALERT output can be used as an interrupt output or
The addressed slave de
The master receives a data byte.
The master asserts NO ACK on SD
The master asserts a stop condition on SDA and the
transaction ends.
SMBALERT is pulled low.
Master
response address (ARA = 0001 100). This is a general call
address, which must not be used as a specific device
address.
The device whose SMBALERT output is low responds to
the alert response address, and the master reads its device
address. The address of the device is now known, and it
can be interrogated in the usual way.
If more than one device’s SMBALERT output is low, the
one with the lowest device address has priority in
accordance with normal SMBus arbitration.
Once the ADT7460 has responded to the alert response
address, the master must read the status registers and the
SMBALERT is cleared only if the error condition has gone
away.
ected to a common
s an interrupting device to identify itself to the host when
a send byte or by write byte operation.
initiates a read operation and sends the alert
Figure 23. Single-Byte Read from a Register
1
S
ADDRESS
SLAVE
SMBALERT line goes low, the following
2
SMBALERT line connected to
W A
vice asserts ACK on SDA.
3
REGISTER
ADDRESS
4
A.
5
A P
6
the
t