LM40CIMT/NOPB National Semiconductor, LM40CIMT/NOPB Datasheet - Page 22

• Manufacturer Part Number: LM40CIMT/NOPB
• Description: IC HARDWARE MONITOR 14-TSSOP
• Manufacturer: National Semiconductor

Specifications of LM40CIMT/NOPB

• Applications: Monitors
• Interface: 1-Wire
• Voltage - Supply: 3 V ~ 3.6 V
• Package / Case: 14-TSSOP
• Mounting Type: Surface Mount
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: *LM40CIMT; *LM40CIMT/NOPB; LM40CIMT

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010 000
010 001
2.0 Register Set
result is ready before the previous result has been read, the new results overwrites the previous result and the Error Function 2
flag (ERF2) for the Voltage-Only function in the Device Status register is set (indicating an overrun event). Reading the
Voltage-Only Measurement Readout register clears also the ERF2 flag.
Readout Resolution The resolution of the readout register is defined in the Voltage Capabilities register. The resolution of the
LM40 is fixed and cannot be modified by software. The voltage readout format is common to all voltage sensors and is 9-bits
unsigned. For over or under input voltage conditions the data is guaranteed to saturate at all "1"s or "0"s so long as Operating
Ratings of the LM40 are adhered to.
Function Event The Voltage-Only Measurement function generates a Function Event to the master whenever a conversion
cycle is completed and new data is stored in the Readout register. When the new data is stored into the Readout register the SF2
bit in the Device Status register is set to 1 and remains set, until it is cleared by reading the Readout register. An Attention Request
is generated on the bus, only if it is enabled by the Attention Enable bit (ATE) in the Control register.
Setup Before Enabling No setup is required for the Voltage-Only Measurement function before it is enabled.
2.10.2 Voltage Capabilities (Addr: 010 000; 10h)
This register defines the format of the voltage data in the voltage readout register. The LM40 only supports one format for all
voltage measurements as defined by the values of this register.
2.10.3 Voltage Readout (Addr: 010 001; 11h)
Add
Add
Reg
Reg
15-9
15-7
2-0
8-4
0-1
4-2
6-5
Bit
Bit
3
Register
Name
Voltage
Capabilities
Register
Name
Voltage
Readout
Type
Type
RO
RO
RO
RO
RO
RO
RO
RO
Resolution. This field defines the total number of significant bits in the Voltage Readout field in the Readout
register for this function. The voltage data is always aligned to the left in the Voltage Readout filed and is
extended with zeros.
001: 9-bit (value for the LM40, for other field values see the SensorPath specification)
RoutSize (Readout Register size). Defines the total size of the Readout register.
0: 16 bits. (value for the LM40 for other field values see the SensorPath specification)
# of Voltage Sensors (Number of Voltage Sensors). Specifies the number of Voltage Sensors supported
by this function.
5: The number of Voltage Sensors. (value for the LM40 for other field values see the SensorPath
specification)
Reserved. Will always read "0".
Reserved. Will always read "0".
SNUM (Sensor Number). This field indicates the number of the current Voltage Sensor, to which the data in
the Voltage Readout field belongs. See Table Analog Input Voltage Mapping for assignments.
Reserved. Will always read "0".
Voltage Readout. This field holds the result of the voltage measurement. The active size of this field for the
LM40 is 9-bits, left justified. See Table Analog Input Voltage Mapping for voltage mapping details.
R/
W
R/
W
R 0051h
R
Val
Val
(Continued)
O
R
O
R
P
P
MSb
MSb
MSb
Bit
Bit
15
15
0
Bit
Bit
14
14
0
Bit
Bit
13
13
0
Reserved
Voltage Readout
Bit
Bit
12
12
0
Bit
Bit
11
11
0
22
Description
Description
Bit
Bit
10
10
0
Bit
Bit
9
0
9
Bit
Bit
8
0
8
# of Voltage Sensors
LSb
Bit
Bit
7
0
7
Reserved
Bit
Bit
6
1
6
0
Bit
Bit
5
0
5
0
Bit
Bit
4
1
4
SNUM
Rout
Size
Bit
Bit
3
0
3
9-bit Resolution
Bit
Bit
2
0
2
Reserved
Bit
Bit
1
0
1
0
LSb
LSb
Bit
Bit
0
1
0
0