ADT7461AR-REEL7 ON Semiconductor, ADT7461AR-REEL7 Datasheet - Page 16
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ADT7461AR-REEL7
Manufacturer Part Number
ADT7461AR-REEL7
Description
IC SENSOR TEMP 2-CH 8SOIC
Manufacturer
ON Semiconductor
Datasheet
1.ADT7461AR-REEL7.pdf
(23 pages)
Specifications of ADT7461AR-REEL7
Rohs Status
RoHS non-compliant
Function
Temp Monitoring System (Sensor)
Topology
ADC, Comparator, Multiplexer, Register Bank
Sensor Type
External & Internal
Sensing Temperature
0°C ~ 127°C, External Sensor
Output Type
SMBus™
Output Alarm
Yes
Output Fan
Yes
Voltage - Supply
3 V ~ 5.5 V
Operating Temperature
-40°C ~ 120°C
Mounting Type
Surface Mount
Package / Case
8-SOIC (3.9mm Width)
ADT7461
When reading data from a register there are two possibilities.
1.
2.
If the ADT7461’s address pointer register value is unknown
or not the desired value, it is necessary to set it to the
correct value before data can be read from the desired data
register. This is done by writing to the ADT7461 as before,
but only the data byte containing the register read address
is sent, since data is not to be written to the register. This is
shown in Figure 18.
A read operation is then performed consisting of the serial
bus address, R/W bit set to 1, followed by the data byte
read from the data register. This is shown in Figure 19.
If the address pointer register is known to be at the desired
address, data can be read from the corresponding data
register without first writing to the address pointer register
SDATA
SCLK
START BY
MASTER
SDATA
SDATA
SCLK
SCLK
A6
1
Figure 17. Writing a Register Address to the Address Pointer Register, then Writing Data to the Selected Register
START BY
MASTER
START BY
MASTER
A5
SERIAL BUS ADDRESS BYTE
A6
A6
1
1
A4
A5
A5
A3
SERIAL BUS ADDRESS BYTE
FRAME 1
SERIAL BUS ADDRESS BYTE
A4
A4
A2
A3
FRAME 1
FRAME 1
A3
Figure 18. Writing to the Address Pointer Register Only
Figure 19. Reading from a Previously Selected Register
SDATA (CONTINUED)
A2
A1
SCLK (CONTINUED)
A2
Rev. 3 | Page 16 of 23 | www.onsemi.com
A1
A0
A1
A0 R/W
A0
R/W
ADT7461
ACK. BY
R/W
ACK. BY
ADT7461
9
ADT7461
ACK. BY
9
D7
1
9
D7
D7
1
1
D7
D6
Although it is possible to read a data byte from a data register
without first writing to the address pointer register, if the
address pointer register is already at the correct value, it is not
possible to write data to a register without writing to the
address pointer register because the first data byte of a write is
always written to the address pointer register.
Also, some of the registers have different addresses for read and
write operations. The write address of a register must be written
to the address pointer if data is to be written to that register, but
it may not be possible to read data from that address. The read
address of a register must be written to the address pointer
before data can be read from that register.
1
D6
D6
ADDRESS POINTER REGISTER BYTE
D6
D5
and the bus transaction shown in Figure 18 can be omitted.
D5
ADDRESS POINTER REGISTER BYTE
D5
DATA BYTE FROM ADT7461
D5
D4
D4
DATA BYTE
FRAME 3
FRAME 2
D4
D4
D3
D3
FRAME 2
FRAME 2
D3
D2
D3
D2
D2
D1
D1
D2
D0
D1
D0
ADT7461
D1
ACK. BY
ADT7461
ACK. BY
D0
9
9
D0
ADT7461
ACK. BY
NACK. BY
STOP BY
MASTER
9
MASTER
STOP BY
MASTER
9
STOP BY
MASTER