EVAL-ADT7462EBZ ON Semiconductor, EVAL-ADT7462EBZ Datasheet - Page 16

• Manufacturer Part Number: EVAL-ADT7462EBZ
• Description: BOARD EVALUATION FOR ADT7462
• Manufacturer: ON Semiconductor
• Type: Temperature Sensorr

Specifications of EVAL-ADT7462EBZ

• Contents: Evaluation Board
• For Use With/related Products: ADT7462
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

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without first writing to the address pointer register, if the
address pointer register is already at the correct value.
without writing to the address pointer register, because the
Write Operations
different types of read and write operations. The ones used
in the ADT7462 are discussed below. The following
abbreviations are used in the diagrams:
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The ADT7462 uses the following SMBus write protocols.
Figure 24. Writing a Register Address to the Address Pointer Register, then Writing Data to the Selected Register
It is possible to read a data byte from a data register
However, it is not possible to write data to a register
The SMBus specification defines several protocols for
If the address pointer register is known to be already at
the desired address, data can be read from the
corresponding data register without first writing to the
address pointer register (see Figure 26).
S ⎯ Start
P ⎯ Stop
R ⎯ Read
W ⎯ Write
A ⎯ Acknowledge
A ⎯ No Acknowledge
SDA
SDA
SCL
SCL
START BY
START BY
MASTER
MASTER
SDA
SCL
START BY
MASTER
A6
A6
1
1
A6
1
A5
A5
Figure 26. Reading Data from a Previously Selected Register
SERIAL BUS ADDRESS BYTE
SERIAL BUS ADDRESS BYTE
Figure 25. Writing to the Address Pointer Register Only
A5
A4
A4
SERIAL BUS ADDRESS BYTE
A4
FRAME 1
FRAME 1
A3
A3
FRAME 1
A3
A2
A2
A2
SDA (CONTINUED)
SCL (CONTINUED)
A1
A1
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A1
A0
A0
A0
R/W
R/W
16
ADT7462
ADT7462
ACK. BY
ACK. BY
R/W
first data byte of a write is always written to the address
pointer register.
protocols, the ADT7462 also supports the read byte protocol
(see System Management Bus Specifications Rev. 2.0 for
more information).
succession, then the master can send a repeat start condition,
instead of a stop condition, to begin a new operation.
Send Byte
command byte to a slave device as follows:
9
9
ADT7462
ACK. BY
In addition to supporting the send byte and receive byte
If several read or write operations must be performed in
In this operation, the master device sends a single
D7
1
9
D7
D7
1. The master device asserts a start condition on SDA.
2. The master sends the 7−bit slave address followed
3. The addressed slave device asserts an ACK on SDA.
4. The master sends a command code.
5. The slave asserts an ACK on SDA.
6. The master asserts a stop condition on SDA to end
1
1
by the write bit (low).
the transaction.
D7
D6
1
D6
D6
ADDRESS POINTER REGISTER BYTE
D6
D5
D5
D5
DATA BYTE FROM ADT7462
ADDRESS POINTER REGISTER BYTE
FRAME 3 DATA BYTE
D5
D4
D4
D4
FRAME 2
FRAME 2
D4
D3
D3
D3
FRAME 2
D2
D3
D2
D2
D2
D1
D1
D1
D1
D0
ADT7462
ACK. BY
D0
D0
BY MASTER
NO ACK.
ADT7462
ACK. BY
D0
9
9
9
ADT7462
ACK. BY
STOP BY
MASTER
9
STOP BY
MASTER
STOP BY
MASTER