se97pw/1 NXP Semiconductors, se97pw/1 Datasheet - Page 9

• Manufacturer Part Number: se97pw/1
• Description: Se97 Memory Module Temp Sensor With Integrated Spd
• Manufacturer: NXP Semiconductors

NXP Semiconductors
SE97_2
Product data sheet
Fig 7. SMBus/I
SDA
SCL
START
A = ACK = Acknowledge bit. W = Write bit = 0. R = Read bit = 1.
S
A6
1
7.9 SMBus/I
2
C-bus write to the Pointer Register
A5
2
device address and write
The data registers in this device are selected by the Pointer Register. At power-up, the
Pointer Register is set to ‘00h’, the location for the Capability Register. The Pointer
Register latches the last location to which it was set. Each data register falls into one of
three types of user accessibility:
A ‘write’ to this device will always include the address byte and the pointer byte. A write to
any register other than the Pointer register requires two data bytes.
Reading this device can take place either of two ways:
The data byte has the most significant bit first. At the end of a read, this device can accept
either Acknowledge (ACK) or No Acknowledge (NACK) from the Master (No Acknowledge
is typically used as a signal for the slave that the Master has read its last byte). It takes this
device 125 ms to measure the temperature. Refer to timing diagrams
Figure 10
A4
3
•
•
•
•
•
Read only
Write only
Write/Read same address
If the location latched in the Pointer Register is correct (most of the time it is expected
that the Pointer Register will point to one of the Temperature Register (as it will be the
data most frequently read), then the read can simply consist of an address byte,
followed by retrieving the two data bytes.
If the Pointer Register needs to be set, then an address byte, pointer byte,
repeat START, and another address byte will accomplish a read.
A3
4
for how to program the device.
2
A2
5
C-bus interface
A1
6
A0
7
Rev. 02 — 12 October 2007
W
8
by device
ACK
9
A
Memory module temp sensor with integrated SPD
D7
1
D6
2
D5
3
register address
D4
4
D3
5
D2
6
D1
7
Figure 7
© NXP B.V. 2007. All rights reserved.
D0
8
by device
ACK
A
9
SE97
to
002aab308
STOP
P
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