LM95231_06 NSC [National Semiconductor], LM95231_06 Datasheet - Page 13

• Manufacturer Part Number: LM95231_06
• Description: Precision Dual Remote Diode Temperature Sensor with SMBus Interface and TruTherm Technology
• Manufacturer: NSC [National Semiconductor]

1.0 Functional Description
1.8 SERIAL INTERFACE RESET
In the event that the SMBus Master is RESET while the
LM95231 is transmitting on the SMBDAT line, the LM95231
must be returned to a known state in the communication
protocol. This may be done in one of two ways:
1. When SMBDAT is LOW, the LM95231 SMBus state
2.0 LM95231 Registers
Command register selects which registers will be read from or written to. Data for this register should be transmitted during the
Command Byte of the SMBus write communication.
P0-P7: Command
Name
Status Register
Configuration Register
Remote Diode Filter Control
Remote Diode Model Type
Select
Remote Diode TruTherm
Mode Control
1-shot
Local Temperature MSB
Remote Temperature 1 MSB
Remote Temperature 2 MSB
Local Temperature LSB
Remote Temperature 1 LSB
Remote Temperature 2 LSB
Manufacturer ID
Revision ID
machine resets to the SMBus idle state if either SMB-
DAT or SMBCLK are held low for more than 35ms
(t
2.0 all devices are to timeout when either the SMBCLK
or SMBDAT lines are held low for 25-35ms. Therefore, to
insure a timeout of all devices on the bus the SMBCLK
or SMBDAT lines must be held low for at least 35ms.
TIMEOUT
). Note that according to SMBus specification
Command
P7
(Hex)
FEh
FFh
02h
03h
06h
30h
07h
0Fh
10h
12h
20h
21h
22h
11h
P6
(Continued)
Default Value
Power-On
P5
(Hex)
Register Summary
A1h
00h
05h
01h
01h
01h
-
-
-
-
-
-
-
-
P4
Command
13
Read/Write
P3
2. When SMBDAT is HIGH, have the master initiate an
1.9 ONE-SHOT CONVERSION
The One-Shot register is used to initiate a single conversion
and comparison cycle when the device is in standby mode,
after which the device returns to standby. This is not a data
register and it is the write operation that causes the one-shot
conversion. The data written to this address is irrelevant and
is not stored. A zero will always be read from this register.
R/W
R/W
R/W
WO
RO
RO
RO
RO
RO
RO
RO
RO
RO
SMBus start. The LM95231 will respond properly to an
SMBus start condition at any point during the communi-
cation. After the start the LM95231 will expect an SMBus
Address address byte.
P2
P1
# of used
bits
3/5
3/5
5
5
2
2
8
8
8
8
2
-
P0
Comments
4 status bits and 1 busy bit
Includes conversion rate
control
Controls thermal diode filter
setting
Selects the 2N3904 or
Pentium 4 processor on 90nm
process thermal diode model
Enables or disables TruTherm
technology for Remote Diode
measurements
Activates one conversion for
all 3 channels if the chip is in
standby mode (i.e.
RUN/STOP bit = 1). Data
transmitted by the host is
ignored by the LM95231.
All unused bits will report zero
All unused bits will report zero
All unused bits will report zero
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