LM96000
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SNAS234C – APRIL 2004 – REVISED MARCH 2013
LM96000 Hardware Monitor with Integrated Fan Control
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FEATURES
KEY SPECIFICATIONS
•
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1
2
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2-wire, SMBus 2.0 Compliant, Serial Digital
Interface
8-bit ΣΔ ADC
Monitors VCCP, 2.5V, 3.3 VSBY, 5.0V, and 12V
Motherboard/processor Supplies
Monitors 2 Remote Thermal Diodes
Programmable Autonomous Fan Control
Based on Temperature Readings
Noise Filtering of Temperature Reading for
Fan Control
1.0°C Digital Temperature Sensor Resolution
3 PWM Fan Speed Control Outputs
Provides High and Low PWM Frequency
Ranges
4 Fan Tachometer Inputs
Monitors 5 VID Control Lines
24-pin TSSOP Package
XOR-tree Test Mode
APPLICATIONS
•
•
Desktop PC
Microprocessor based equipment
– (e.g. Base-stations, Routers, ATMs, Point of
Sales)
•
•
Voltage Measurement Accuracy ±2% FS (max)
Resolution 8-bits, 1°C
Temperature Sensor Accuracy ±3°C (max)
Temperature Range
– LM96000 Operational 0°C to +85°C
– Remote Temp Accuracy 0°C to +125°C
Power Supply Voltage +3.0V to +3.6V
Power Supply Current 0.53 mA
DESCRIPTION
The LM96000, hardware monitor, has a two wire
digital interface compatible with SMBus 2.0. Using an
8-bit ΣΔ ADC, the LM96000 measures:
• the temperature of two remote diode connected
transistors as well as its own die
• the VCCP, 2.5V, 3.3VSBY, 5.0V, and 12V
supplies (internal scaling resistors).
To set fan speed, the LM96000 has three PWM
outputs that are each controlled by one of three
temperature zones. High and low PWM frequency
ranges are supported. The LM96000 includes a
digital filter that can be invoked to smooth
temperature readings for better control of fan speed.
The LM96000 has four tachometer inputs to measure
fan speed. Limit and status registers for all measured
values are included.
1
2
Please be aware that an important notice concerning availability, standard warranty, and use in critical applications of
Texas Instruments semiconductor products and disclaimers thereto appears at the end of this data sheet.
All trademarks are the property of their respective owners.
PRODUCTION DATA information is current as of publication date.
Products conform to specifications per the terms of the Texas
Instruments standard warranty. Production processing does not
necessarily include testing of all parameters.
Copyright © 2004–2013, Texas Instruments Incorporated
LM96000
SNAS234C – APRIL 2004 – REVISED MARCH 2013
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Block Diagram
SERIAL BUS
INTERFACE
VID0
VID1
VID2
VID3
VID4
VID0-4
REGISTER
SMBDAT
SMBCLK
VOLTAGE, FAN SPEED,
TEMPERATURE, AND
LIMIT VALUE REGISTERS
TACH1
TACH2
FAN SPEED
COUNTER
TACH3
TACH4/
Address Select
LIMIT COMPARATORS
VDD
STEPPING AND
DEVICE ID
REGISTERS
3.3SBY
5VIN
STATUS REGISTERS
CONFIGURATION
REGISTERS
ADDRESS
POINTER
REGISTER
12VIN
2.5VIN
VCCP_IN
INPUT
ATTENUATORS,
EXTERNAL DIODE
SIGNAL
CONDITIONING,
AND
ANALOG
MULTIPLEXER
REMOTE1+
REMOTE1REMOTE2REMOTE2+
FAN TMIN/TRANGE/
HYST REGISTERS
8-bit
6' ADC
PWM2
FAN CHARACTERISTICS
FAN SPEED CONFIG.
REGISTERS
BANDGAP
REFERENCE
INTERNAL
TEMP
SENSOR
PWM1
SPIKE SMOOTHING
PWM3/
Address
Enable
FAN PWM CONTROL
& PWM VALUE
REGISTERS
Connection Diagram
Top View
SMBDAT
1
24
PWM1/xTESTOUT
SMBCLK
2
23
VCCP_IN
GND
3
22
2.5V
3.3V
4
21
12V
VID0
5
20
5V
VID1
6
19
VID4
VID2
7
18
REMOTE1+
VID3
8
17
REMOTE1-
TACH3
9
16
REMOTE2+
PWM2
10
15
REMOTE2-
TACH1
11
14
TACH4/AddSel
TACH2
12
13
PWM3/AddEnable
LM96000
Figure 1. 24-Pin TSSOP Package
2
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Pin Descriptions
SMBus
Processor
VID Lines
Name
Pin No.
Type
SMBDAT
1
Digital I/O
(Open-Drain)
System Management Bus Data. Open-drain output. 5V tolerant, SMBus
2.0 compliant.
SMBCLK
2
Digital Input
System Management Bus Clock. Tied to Open-drain output. 5V tolerant,
SMBus 2.0 compliant.
VID0
5
Digital Input
Voltage identification signal from the processor. This value is read in the
VID0–VID4 Status Register.
VID1
6
Digital Input
Voltage identification signal from the processor. This value is read in the
VID0–VID4 Status Register.
VID2
7
Digital Input
Voltage identification signal from the processor. This value is read in the
VID0–VID4 Status Register.
VID3
8
Digital Input
Voltage identification signal from the processor. This value is read in the
VID0–VID4 Status Register.
VID4
19
Digital Input
Voltage identification signal from the processor. This value is read in the
VID0–VID4 Status Register.
3.3V
4
POWER
+3.3V pin. Can be powered by +3.3V Standby power if monitoring in low
power states is required. This pin also serves as the analog input to
monitor the 3.3V supply. This pin should be bypassed with a 0.1µf
capacitor in parallel with 100pf. A bulk capacitance of approximately 10µf
needs to be in the near vicinity of the LM96000.
Power
Voltage
Inputs
Remote
Diodes
Fan
Tachometer
Inputs
Fan Control
Name and Function/Connection
GND
3
GROUND
5V
20
Analog Input
Ground for all analog and digital circuitry.
Analog input for +5V monitoring.
12V
21
Analog Input
Analog input for +12V monitoring.
2.5V
22
Analog Input
Analog input for +2.5V monitoring.
VCCP_IN
23
Analog Input
Analog input for VCCP (processor voltage) monitoring.
Remote1+
18
Remote Thermal
Diode Positive
Input
Positive input (current source) from the first remote thermal diode.
Serves as the positive input into the A/D. Connected to THERMDA pin of
Pentium processor or the base of a diode connected MMBT3904 NPN
transistor.
Remote1−
17
Remote Thermal
Diode Negative
Input
Negative input (current sink) from the first remote thermal diode. Serves
as the negative input into the A/D. Connected to THERMDC pin of
Pentium processor or the emmiter of a diode connected MMBT3904
NPN transistor.
Remote2+
16
Remote Thermal
Diode Positive
Output
Positive input (current source) from the first remote thermal diode.
Serves as the positive input into the A/D. Connected to THERMDA pin of
Pentium processor or the base of a diode connected MMBT3904 NPN
transistor.
Remote2−
15
Remote Thermal
Diode Negative
Input
Negative input (current sink) from the first remote thermal diode. Serves
as the negative input into the A/D. Connected to THERMDC pin of
Pentium processor or the emmiter of a diode connected MMBT3904
NPN transistor.
TACH1
11
Digital Input
Input for monitoring tachometer output of fan 1.
TACH2
12
Digital Input
Input for monitoring tachometer output of fan 2.
TACH3
9
Digital Input
Input for monitoring tachometer output of fan 3.
TACH4/Address
Select
14
Digital Input
Input for monitoring tachometer output of fan 4. If in Address Select
Mode, determines the SMBus address of the LM96000.
PWM1/xTest Out
24
Digital Open-Drain Fan speed control 1. When in XOR tree test mode, functions as XOR
Output
Tree output.
PWM2
10
Digital Open-Drain Fan speed control 2.
Output
PWM3/Address
Enable
13
Digital Open-Drain Fan speed control 3. Pull to ground at power on to enable Address
Output
Select Mode (Address Select pin controls SMBus address of the device).
These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam
during storage or handling to prevent electrostatic damage to the MOS gates.
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LM96000
SNAS234C – APRIL 2004 – REVISED MARCH 2013
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Absolute Maximum Ratings (1) (2) (3)
Supply Voltage, V+
−0.5V to 6.0V
Voltage on Any Digital Input or
Output Pin
−0.5V to 6.0V
Voltage on 12V Analog Input
−0.5V to 16V
−0.5V to 6.66V
Voltage on 5V Analog Input
−0.5V to (V+ + 0.05V)
Voltage on Remote1+, Remote2+,
Current on Remote1−, Remote2−
±1 mA
−0.5V to 6.0V
Voltage on Other Analog Inputs
Input Current on Any Pin
Package Input Current
(4)
±5 mA
(4)
±20 mA
Package Dissipation at TA = 25°C
ESD Susceptibility
(6)
See
Human Body Model
(5)
2500V
Machine Model
250V
−65°C to +150°C
Storage Temperature
Soldering process must comply with reflow temperature profile specifications. See www.ti.com/packaging (7)
(1)
(2)
(3)
(4)
(5)
(6)
(7)
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is functional, but do not ensure specific performance limits. For ensured specifications and test conditions, see the
Electrical Characteristics. The ensured specifications apply only for the test conditions listed. Some performance characteristics may
degrade when the device is not operated under the listed test conditions.
All voltages are measured with respect to GND, unless otherwise noted.
If Military/Aerospace specified devices are required, please contact the TI Sales Office/ Distributors for availability and specifications.
When the input voltage (VIN) at any pin exceeds the power supplies (VIN < GND or VIN >V+ ), the current at that pin should be limited to
5mA. The 20mA maximum package input current rating limits the number of pins that can safely exceed the power supplies with an
input current of 5mA to four. Parasitic components and/or ESD protection circuitry are shown below for the LM96000's pins. The nominal
breakdown voltage the zener is 6.5V. Care should be taken not to forward bias the parasitic diode D1 present on pins D+ and D−. Doing
so by more that 50 mV may corrupt temperature measurements. SNP stands for snap-back device.
Thermal resistance junction-to-ambient when attached to a double-sided printed circuit board with 1 oz. foil is 113 °C/W.
Human body model, 100pF discharged through a 1.5kΩ resistor. Machine model, 200pF discharged directly into each pin.
Reflow temperature profiles are different for packages containing lead (Pb) than for those that do not.
Operating Ratings (1) (2)
0°C ≤ TA ≤ +85°C
LM96000 Operating Temperature Range
0°C ≤ TD ≤ +125°C
Remote Diode Temperature Range
Supply Voltage (3.3V nominal)
+3.0V to +3.6V
VIN Voltage Range
−0.05V to 16V
+12V VIN
−0.05V to 6.66V
+5V VIN
+3.3V VIN
3.0V to 4.4V
−0.05V to (V+ + 0.05V)
VCCP_IN and All Other Inputs
−0.05V to 5.5V
VID0–VID4
Typical Supply Current
(1)
(2)
4
0.53 mA
Absolute Maximum Ratings indicate limits beyond which damage to the device may occur. Operating Ratings indicate conditions for
which the device is functional, but do not ensure specific performance limits. For ensured specifications and test conditions, see the
Electrical Characteristics. The ensured specifications apply only for the test conditions listed. Some performance characteristics may
degrade when the device is not operated under the listed test conditions.
All voltages are measured with respect to GND, unless otherwise noted.
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DC Electrical Characteristics
The following specifications apply for V+ = 3.0V to 3.6V, and all analog input source impedance RS = 50Ω unless otherwise
specified in conditions. Boldface limits apply for TA = TJ over TMIN =0°C to TMAX=85°C; all other limits TA =TJ= 25°C. TA is
the ambient temperature of the LM96000; TJ is the junction temperature of the LM96000; TD is the thermal diode junction
temperature.
Parameter
Typical
Limits
(2)
Units
(Limits)
Converting, Interface and
Fans Inactive, Peak Current
1.8
3.5
mA (max)
Converting, Interface and
Fans Inactive, Average
Current
0.53
Test Conditions
(1)
POWER SUPPLY CHARACTERISTICS
Supply Current
(3)
Power-On Reset Threshold Voltage
mA
1.6
V (min)
2.8
V (max)
TEMPERATURE TO DIGITAL CONVERTER CHARACTERISTICS
Resolution
Temperature Accuracy (See
Processor Type)
1
8
(4)
for Thermal Diode
TD=25°C
TD=0°C to 100°C
±1
TD=100°C to 125°C
External Diode Current Source
±2.5
°C (max)
±3
°C (max)
±4
°C (max)
±1
±3
°C (max)
High Level
188
280
µA (max)
Low Level
11.75
Temperature Accuracy using Internal Diode. (5) See (6)
for the thermal resistance to be used in the selfheating calculation.
IDS
°C
Bits
External Diode Current Ratio
µA
16
ANALOG TO DIGITAL CONVERTER CHARACTERISTICS
TUE
Total Unadjusted Error (7)
DNL
Differential Non-linearity
1
Power Supply Sensitivity
±1
Total Monitoring Cycle Time
±2
(8)
All Voltage and Temperature
readings
Input Resistance, all analog inputs
%FS
(max)
LSB
%/V
182
200
ms (max)
210
140
kΩ (min)
400
kΩ (max)
8
mA (min)
0.4
V (max)
DIGITAL OUTPUT: PWM1, PWM2, PWM3, XTESTOUT
IOL
Logic Low Sink Current
VOL=0.4V
VOL
Logic Low Level
IOUT = +8 mA
(1)
(2)
(3)
(4)
(5)
(6)
(7)
(8)
Typicals are at TA = 25°C and represent most likely parametric norm.
Limits are specified to TI's AOQL (Average Outgoing Quality Level).
The average current can be calculated from the peak current using the following equation:Quiescent current will not increase
substantially with an SMBus transaction.
The accuracy of the LM96000CIMT is ensured when using the thermal diode of Intel Pentium 4 90nm processors or any thermal diode
with a non-ideality of 1.011 and series resistance of 3.33Ω. When using a 2N3904 type transistor as a thermal diode the error band will
be typically shifted by -?°C.
Local temperature accuracy does not include the effects of self-heating. The rise in temperature due to self-heating is the product of the
internal power dissipation of the LM96000 and the thermal resistance.
Thermal resistance junction-to-ambient when attached to a double-sided printed circuit board with 1 oz. foil is 113 °C/W.
TUE , total unadjusted error, includes ADC gain, offset, linearity and reference errors. TUE is defined as the "actual Vin" to achieve a
given code transition minus the "theoretical Vin" for the same code. Therefore, a positive error indicates that the input voltage is greater
than the theoretical input voltage for a given code. If the theoretical input voltage was applied to an LM96000 that has positive error, the
LM96000's reading would be less than the theoretical.
This specification is provided only to indicate how often temperature and voltage data is updated. The LM96000 can be read at any time
without regard to conversion state (and will yield last conversion result).
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DC Electrical Characteristics (continued)
The following specifications apply for V+ = 3.0V to 3.6V, and all analog input source impedance RS = 50Ω unless otherwise
specified in conditions. Boldface limits apply for TA = TJ over TMIN =0°C to TMAX=85°C; all other limits TA =TJ= 25°C. TA is
the ambient temperature of the LM96000; TJ is the junction temperature of the LM96000; TD is the thermal diode junction
temperature.
Parameter
Test Conditions
Typical
(1)
Limits
(2)
Units
(Limits)
0.4V
V (max)
10
µA (max)
2.1
V (min)
0.8
V (max)
SMBUS OPEN-DRAIN OUTPUT: SMBDAT
VOL
Logic Low Output Voltage
IOUT = +4 mA
IOH
High Level Output Current
VOUT = V+
0.1
SMBUS INPUTS: SMBCLK. SMBDAT
VIH
Logic Input High Voltage
VIL
Logic Input Low Voltage
VHYST
Logic Input Hysteresis Voltage
300
mV
DIGITAL INPUTS: ALL
VIH
Logic Input High Voltage
VIL
Logic Input Low Voltage
VTH
Logic Input Threshold Voltage
IIH
Logic High Input Current
VIN = V+
IIL
Logic Low Input Current
VIN = GND
CIN
Digital Input Capacitance
2.1
V (min)
0.8
V (max)
0.005
10
µA (max)
−0.005
−10
µA (max)
1.5
V
20
pF
AC Electrical Characteristics
The following specifications apply for V+ = 3.0V to 3.6V unless otherwise specified in conditions. Boldface limits apply for
TA = TJ over TMIN =0°C to TMAX=85°C; all other limits TA =TJ= 25°C.
Limits
(2)
Units
(Limits)
Fan Count Accuracy
±10
% (max)
Fan Full-Scale Count
65536
(max)
1.4
sec (max)
±10
% (max)
Parameter
Test Conditions
Typical
(1)
TACHOMETER ACCURACY
Fan Counter Clock Frequency
90
Fan Count Conversion Time
0.7
kHz
FAN PWM OUTPUT
Frequency Setting Accuracy
Frequency Range
Duty-Cycle Range
10
30
Low frequency range
Hz
kHz
0 to 100
% (max)
Duty-Cycle Resolution (8-bits)
0.390625
%
Spin-Up Time Interval Range
100
4000
ms
ms
Spin-Up Time Interval Accuracy
±10
% (max)
±10
% (max)
SPIKE SMOOTHING FILTER
Time Interval Deviation
Time Interval Range
(1)
(2)
6
35
0.8
sec
sec
Typicals are at TA = 25°C and represent most likely parametric norm.
Limits are specified to TI's AOQL (Average Outgoing Quality Level).
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AC Electrical Characteristics (continued)
The following specifications apply for V+ = 3.0V to 3.6V unless otherwise specified in conditions. Boldface limits apply for
TA = TJ over TMIN =0°C to TMAX=85°C; all other limits TA =TJ= 25°C.
Parameter
Typical
Test Conditions
(1)
Limits
(2)
Units
(Limits)
SMBUS TIMING CHARACTERISTICS
fSMB
SMBus Operating Frequency
10
100
kHz (min)
kHz (max)
fBUF
SMBus Free Time Between Stop And
Start Condition
4.7
µs (min)
tHD_STA
Hold Time After (Repeated) Start
Condition (after this period, the first clock
is generated)
4.0
µs (min)
tSU:STA
Repeated Start Condition Setup Time
4.7
µs (min)
tSU:STO
Stop Condition Setup Time
4.0
µs (min)
tHD:DAT
Data Output Hold Time
300
ns (min)
930
ns (max)
tSU:DAT
Data Input Setup Time
250
ns (min)
tTIMEOUT
Data And Clock Low Time To Reset Of
SMBus Interface Logic (3)
25
35
ms (min)
ms (max)
tLOW
Clock Low Period
4.7
µs (min)
tHIGH
Clock High Period
4.0
50
µs (min)
µs (max)
tF
Clock/Data Fall Time
300
ns (max)
tR
Clock/Data Rise Time
1000
ns (max)
tPOR
Time from Power-On-Reset to LM96000
Reset and Operational
500
ms (max)
(3)
V+ > 2.8V
Holding the SMBDAT and/or SMBCLK lines Low for a time interval greater than tTIMEOUT will reset the LM96000's SMBus state machine,
therefore setting the SMBDAT pin to a high impedance state.
tLOW
tR
tF
VIH
SMBCLK
VIL
tHD;STA
tHD;DAT
tBUF
tHIGH
tSU;STA
tSU;DAT
tSU;STO
VIH
SMBDAT
VIL
P
S
S
Pin
No.
Pin Name
Circuit
1
SMBDAT
A
2
SMBCLK
3
GND
4
3.3V
P
All Input Circuits
PIN
D1
SNP
B
GND
Figure 2. Circuit A
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Pin
No.
Pin Name
Circuit
5
VID0
A
6
VID1
7
VID2
8
VID3
9
TACH3
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All Input Circuits
V+
ESD
Clamp
D2
160 k
D3
80 k
D1
6.5V
GND
Figure 3. Circuit B
10
PWM2
11
TACH1
12
TACH2
13
PWM3/AddEnable
14
TACH4/AddSel
V+
D3
50:
PIN
D1
D2
ESD
CLAMP
D4
6.5V
GND
Figure 4. Circuit C
15
REMOTE2−
C
16
REMOTE2+
D
17
REMOTE1−
C
18
REMOTE1+
D
19
VID4
A
V+
D2
50:
PIN
D1
SNP
ESD
CLAMP
D3
6.5V
GND
Figure 5. Circuit D
20
5V
21
12V
22
2.5V
23
VCCP_IN
24
PWM1/xTEXTOUT
E
V+
D2
6.5V
D3
PIN
D1
A
SNP
ESD
Clamp
R1
R2
GND
Figure 6. Circuit E
FUNCTIONAL DESCRIPTION
1.0 SMBUS
The LM96000 is compatible with devices that are compliant to the SMBus 2.0 specification. More information on
this bus can be found at: http://www.smbus.org/. Compatibility of SMBus2.0 to other buses is discussed in the
SMBus 2.0 specification.
1.1 Addressing
LM96000 is designed to be used primarily in desktop systems that require only one monitoring device.
If only one LM96000 is used on the motherboard, the designer should be sure that the PWM3/Address Enable
pin is High during the first SMBus communication addressing the LM96000. PWM3/Address Enable is an open
drain I/O pin that at power-on defaults to the input state of Address Enable. A maximum of 10k pull-up resistance
on PWM3/Address Enable is required to assure that the SMBus address of the device will be locked at 010
1110b, which is the default address of the LM96000.
During the first SMBus communication TACH4 and PWM3 can be used to change the SMBus address of the
LM96000 to 0101101b or 0101100b. LM96000 address selection procedure:
• A 10 kΩ pull-down resistor to ground on the PWM3/Address Enable pin is required. Upon power up, the
LM96000 will be placed into Address Enable mode and assign itself an SMBus address according to the state
of the Address Select input. The LM96000 will latch the address during the first valid SMBus transaction in
which the first five bits of the targeted address match those of the LM96000 address, 0 1011b. This feature
eliminates the possibility of a glitch on the SMBus interfering with address selection. When the
8
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PWM3/Address Enable pin is not used to change the SMBus address of the LM96000, it will remain in a high
state until the first communication with the LM96000. After the first SMBus transaction is completed PWM3
and TACH4 will return to normal operation.
Address Enable
Address Select
Board Implementation
SMBus Address
0
0
Pulled to ground through a 10 kΩ 010 1100b, 2Ch
resistor
0
1
Pulled to 3.3V or to GND through 010 1101b, 2Dh
a 10 kΩ resistor
1
X
Pulled to 3.3V through a 10 kΩ
resistor
010 1110b, 2Eh
In this way, up to three LM96000 devices can exists on an SMBus at any time. Multiple LM96000 devices can be
used to monitor additional processors and temperature zones. When using the non-default addresses the TACH4
and PWM3 will not function. As shown in the timing diagram the Address Enable pin must remain low in order for
the latched address to remain in effect. If the address enable pin is pulled high after the first SMBus
communication, then the LM96000 SMBus address will revert to the default value (2Eh) after the first five clocks
of next SMBus communication.
Latch state of AE and AS
if first 5 address bits are
correct for SMBus
address 2Ch and 2Dh
selection.
first 5 address bits
START
0
1
0
1
1
SMBCLK
SMBDAT
Address
Enable
Address
Select
Figure 7. Address Latch Enable low during and after first communication
first 5 address bits
START
0
1
0
1
SMBCLK
1
Latch state of AE if
first 5 address bits
are correct for
SMBus address 2Eh
selection.
SMBDAT
Address
Enable
Address
Select
Figure 8. Address Latch Enable high during first communication
2.0 FAN REGISTER DEVICE SET-UP
The BIOS will follow the following steps to configure the fan registers on the LM96000. The registers
corresponding to each function are listed. All steps may not be necessary if default values are acceptable.
Regardless of all changes made by the BIOS to the fan limit and parameter registers during configuration, the
LM96000 will continue to operate based on default values until the START bit (bit 0), in the
Ready/Lock/Start/Override register (address 40h), is set. Once the fan mode is updated, by setting the START
bit to 1, the LM96000 will operate using the values that were set by the BIOS in the fan control limit and
parameter registers (adress 5Ch through 6Eh).
1. Set limits and parameters (not necessarily in this order):
–
– [5F-61h] Set PWM frequencies and auto fan control range.
–
– [62-63h] Set spike smoothing and min/off.
–
– [5C-5Eh] Set the fan spin-up delays.
–
– [5C-5Eh] Match each fan with a corresponding thermal zone.
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–
– [67-69h] Set the fan temperature limits.
–
– [6A-6Ch] Set the temperature absolute limits.
–
– [64-66h] Set the PWM minimum duty cycle.
–
– [6D-6Eh] Set the temperature Hysteresis values.
2. [40h] Set bit 0 (START) to update fan control and limit register values and start fan control based on these
new values.
3. [40h] Set bit 1 (LOCK) to lock the fan limit and parameter registers (optional).
3.0 AUTO FAN CONTROL OPERATING MODE
The LM96000 includes the circuitry for automatic fan control. In Auto Fan Mode, the LM96000 will automatically
adjust the PWM duty cycle of the PWM outputs. PWM outputs are assigned to a thermal zone based on the fan
configuration registers. It is possible to have more than one PWM output assigned to a thermal zone. For
example, PWM outputs 2 and 3, connected to two chassis fans, may both be controlled by thermal zone 2. At
any time, the temperature of a zone exceeds its absolute limit, all PWM outputs will go to 100% duty cycle to
provide maximum cooling to the system.
4.0 REGISTER SET
Register Read/
Address Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
20h
R
21h
R
2.5V
7
6
5
4
3
2
1
0
N/A
VCCP_I
N
7
6
5
4
3
2
1
0
N/A
22h
R
3.3V
7
6
5
4
3
2
1
0
N/A
23h
R
5V
7
6
5
4
3
2
1
0
N/A
24h
R
12V
7
6
5
4
3
2
1
0
N/A
25h
R
Process
or
(Zone1)
Temp
7
6
5
4
3
2
1
0
N/A
26h
R
Internal
(Zone2)
Temp
7
6
5
4
3
2
1
0
N/A
27h
R
Remote
(Zone3)
Temp
7
6
5
4
3
2
1
0
N/A
28h
R
Tach1
LSB
7
6
5
4
3
2
LEVEL1
LEVEL0
N/A
29h
R
Tach1
MSB
15
14
13
12
11
10
9
8
N/A
2Ah
R
Tach2
LSB
7
6
5
4
3
2
LEVEL1
LEVEL0
N/A
2Bh
R
Tach2
MSB
15
14
13
12
11
10
9
8
N/A
2Ch
R
Tach3
LSB
7
6
5
4
3
2
LEVEL1
LEVEL0
N/A
2Dh
R
Tach3
MSB
15
14
13
12
11
10
9
8
N/A
2Eh
R
Tach4
LSB
7
6
5
4
3
2
LEVEL1
LEVEL0
N/A
2Fh
R
Tach4
MSB
15
14
13
12
11
10
9
8
N/A
30h
R/W
Fan1
Current
PWM
Duty
7
6
5
4
3
2
1
0
N/A
10
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Register Read/
Address Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
31h
R/W
Fan2
Current
PWM
Duty
7
6
5
4
3
2
1
0
N/A
32h
R/W
Fan3
Current
PWM
Duty
7
6
5
4
3
2
1
0
N/A
3Eh
R
Compan
y ID
7
6
5
4
3
2
1
0
01h
3Fh
R
Version/
Stepping
VER3
VER2
VER1
VER0
STP3
STP2
STP1
STP0
68h
40h
R/W
Ready/L
ock/Start
/Overrid
e
RES
RES
RES
RES
OVRID
READY
LOCK
START
00h
41h
R
Interrupt
Status
Register
1
ERR
ZN3
ZN2
ZN1
5V
3.3V
VCCP
2.5V
00h
42h
R
Interrupt
Status
Register
2
ERR2
ERR1
FAN4
FAN3
FAN2
FAN1
RES
12V
00h
43h
R
VID0–4
RES
RES
RES
VID4
VID3
VID2
VID1
VID0
N/A
44h
R/W
2.5V
Low
Limit
7
6
5
4
3
2
1
0
00h
45h
R/W
2.5V
High
Limit
7
6
5
4
3
2
1
0
FFh
46h
R/W
VCCP
Low
Limit
7
6
5
4
3
2
1
0
00h
47h
R/W
VCCP
High
Limit
7
6
5
4
3
2
1
0
FFh
48h
R/W
3.3V
Low
Limit
7
6
5
4
3
2
1
0
00h
49h
R/W
3.3V
High
Limit
7
6
5
4
3
2
1
0
FFh
4Ah
R/W
5V Low
Limit
7
6
5
4
3
2
1
0
00h
4Bh
R/W
5V High
Limit
7
6
5
4
3
2
1
0
FFh
4Ch
R/W
12V Low
Limit
7
6
5
4
3
2
1
0
00h
4Dh
R/W
12V
High
Limit
7
6
5
4
3
2
1
0
FFh
4Eh
R/W
Process
or
(Zone1)
Low
Temp
7
6
5
4
3
2
1
0
81h
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Register Read/
Address Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
4Fh
R/W
Process
or
(Zone1)
High
Temp
7
6
5
4
3
2
1
0
7Fh
50h
R/W
Internal
(Zone2)
Low
Temp
7
6
5
4
3
2
1
0
81h
51h
R/W
Internal
(Zone2)
High
Temp
7
6
5
4
3
2
1
0
7Fh
52h
R/W
Remote
(Zone3)
Low
Temp
7
6
5
4
3
2
1
0
81h
53h
R/W
Remote
(Zone3)
High
Temp
7
6
5
4
3
2
1
0
7Fh
54h
R/W
Tach1
Minimum
LSB
7
6
5
4
3
2
1
0
FFh
55h
R/W
Tach1
Minimum
MSB
15
14
13
12
11
10
9
8
FFh
56h
R/W
Tach2
Minimum
LSB
7
6
5
4
3
2
1
0
FFh
57h
R/W
Tach2
Minimum
MSB
15
14
13
12
11
10
9
8
FFh
58h
R/W
Tach3
Minimum
LSB
7
6
5
4
3
2
1
0
FFh
59h
R/W
Tach3
Minimum
MSB
15
14
13
12
11
10
9
8
FFh
5Ah
R/W
Tach4
Minimum
LSB
7
6
5
4
3
2
1
0
FFh
5Bh
R/W
Tach4
Minimum
MSB
15
14
13
12
11
10
9
8
FFh
5Ch
R/W
Fan1
Configur
ation
ZON2
ZON1
ZON0
INV
RES
SPIN2
SPIN1
SPIN0
62h
✓
5Dh
R/W
Fan2
Configur
ation
ZON2
ZON1
ZON0
INV
RES
SPIN2
SPIN1
SPIN0
62h
✓
5Eh
R/W
Fan3
Configur
ation
ZON2
ZON1
ZON0
INV
RES
SPIN2
SPIN1
SPIN0
62h
✓
5Fh
R/W
Fan1
Range/F
requenc
y
RAN3
RAN2
RAN1
RAN0
HLFRQ
FRQ2
FRQ1
FRQ0
C4h
✓
60h
R/W
Fan2
Range/F
requenc
y
RAN3
RAN2
RAN1
RAN0
HLFRQ
FRQ2
FRQ1
FRQ0
C4h
✓
12
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Register Read/
Address Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
Lock?
61h
R/W
Fan3
Range/F
requenc
y
RAN3
RAN2
RAN1
RAN0
HLFRQ
FRQ2
FRQ1
FRQ0
C4h
✓
62h
R/W
Min/Off,
Zone1
Spike
Smoothi
ng
OFF3
OFF2
OFF1
RES
ZN1E
ZN1-2
ZN1-1
ZN1-0
00H
✓
63h
R/W
Zone2,
Zone3
Spike
Smoothi
ng
ZN2E
ZN2-2
ZN2-1
ZN2-0
ZN3E
ZN3-2
ZN3-1
ZN3-0
00h
✓
64h
R/W
Fan1
PWM
Minimum
7
6
5
4
3
2
1
0
80h
✓
65h
R/W
Fan2
PWM
Minimum
7
6
5
4
3
2
1
0
80h
✓
66h
R/W
Fan3
PWM
Minimum
7
6
5
4
3
2
1
0
80h
✓
67h
R/W
Zone1
Fan
Temp
Limit
7
6
5
4
3
2
1
0
5Ah
✓
68h
R/W
Zone2
Fan
Temp
Limit
7
6
5
4
3
2
1
0
5Ah
✓
69h
R/W
Zone3
Fan
Temp
Limit
7
6
5
4
3
2
1
0
5Ah
✓
6Ah
R/W
Zone1
Temp
Absolute
Limit
7
6
5
4
3
2
1
0
64h
✓
6Bh
R/W
Zone2
Temp
Absolute
Limit
7
6
5
4
3
2
1
0
64h
✓
6Ch
R/W
Zone3
Temp
Absolute
Limit
7
6
5
4
3
2
1
0
64h
✓
6Dh
R/W
Zone1,
Zone2
Hysteres
is
H1-3
H1-2
H1-1
H1-0
H2-3
H2-2
H2-1
H2-0
44h
✓
6Eh
R/W
Zone3
Hysteres
is
H3-3
H3-2
H3-1
H3-0
RES
RES
RES
RES
40h
✓
6Fh
R/W
XOR
Test
Tree
Enable
RES
RES
RES
RES
RES
RES
RES
XEN
00h
✓
74h
R/W
Tach
Monitor
Mode
RES
RES
T3/4-1
T3/4-0
T2-1
T2-0
T1-1
T1-0
00h
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Register Read/
Address Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
Lock?
75h
Fan
Spin-up
Mode
RES
RES
RES
RES
RES
PWM3
SU
PWM2
SU
PWM1
SU
7h
✓
R/W
4.1 Register 20-24h: Voltage Reading
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 0
(LSB)
Bit 1
Default
Value
20h
R
2.5V
7
6
5
4
3
2
1
0
N/A
21h
R
VCCP
7
6
5
4
3
2
1
0
N/A
22h
R
3.3V
7
6
5
4
3
2
1
0
N/A
23h
R
5V
7
6
5
4
3
2
1
0
N/A
24h
R
12V
7
6
5
4
3
2
1
0
N/A
The Register Names difine the typical input voltage at which the reading is ¾ full scale or C0h.
The Voltage Reading registers are updated automatically by the LM96000 at a minimum frequency of 4 Hz.
These registers are read only — a write to these registers has no effect.
4.2 Register 25-27h: Temperature Reading
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 0
(LSB)
Bit 1
Default
Value
25h
R
Processo
r (Zone1)
Temp
7
6
5
4
3
2
1
0
N/A
26h
R
Internal
(Zone2)
Temp
7
6
5
4
3
2
1
0
N/A
27h
R
Remote
(Zone3)
Temp
7
6
5
4
3
2
1
0
N/A
The Temperature Reading registers reflect the current temperatures of the internal and remote diodes. Processor
(Zone1) Temp register reports the temperature measured by the thermal diode connected to the Remote1− and
Remote1+ pins, Remote (Zone3) Temp register reports the temperature measured by the thermal diode
connected to the the Remote2− and Remote2+ pins, and the Internal (Zone2) Temp register reports the
temperature measured by the internal (junction) temperature sensor. Temperatures are represented as 8 bit, 2’s
complement, signed numbers, in Celsius, as shown below in Table 1. The Temperature Reading register will
return a value of 80h if the remote diode pins are not used by the board designer or are not functioning properly.
This reading will cause the zone limit bit(s) (bits 6 and 4) in the Interrupt Status Register (41h) and the remote
diode fault status bit(s) (bit 6 or 7) in the Interrupt Status Register 2 (42h) to be set. The Temperature Reading
registers are updated automatically by the LM96000 at a minimum frequency of 4 Hz. These registers are read
only — a write to these registers has no effect.
Table 1. Temperature vs Register Reading
14
Temperature
Reading (Dec)
Reading (Hex)
−127°C
−127
81h
.
.
.
.
.
.
.
.
.
−50°C
−50
CEh
.
.
.
.
.
.
.
.
.
0°C
0
00h
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Table 1. Temperature vs Register Reading (continued)
Temperature
Reading (Dec)
Reading (Hex)
.
.
.
.
.
.
.
.
.
127°C
127
7Fh
(SENSOR ERROR)
80h
4.3 Register 28-2Fh: Fan Tachometer Reading
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
28h
29h
R
R
Tach1
LSB
Tach1
MSB
7
15
6
14
5
13
4
12
3
11
2
10
LEVEL1
9
LEVEL0
8
N/A
N/A
2Ah
2Bh
R
R
Tach2
LSB
Tach2
MSB
7
15
6
14
5
13
4
12
3
11
2
10
LEVEL1
9
LEVEL0
8
N/A
N/A
2Ch
2Dh
R
R
Tach3
LSB
Tach3
MSB
7
15
6
14
5
13
4
12
3
11
2
10
LEVEL1
9
LEVEL0
8
N/A
N/A
2Eh
2Fh
R
R
Tach4
LSB
Tach4
MSB
7
15
6
14
5
13
4
12
3
11
2
10
LEVEL1
9
LEVEL0
8
N/A
N/A
The Fan Tachometer Reading registers contain the number of 11.111 µs periods (90 kHz) between full fan
revolutions. The results are based on the time interval of two tachometer pulses, since most fans produce two
tachometer pulses per full revolution. These registers will be updated at least once every second.
The value, for each fan, is represented by a 16-bit unsigned number.
The Fan Tachometer Reading registers will always return an accurate fan tachometer measurement, even when
a fan is disabled or non-functional.
The least two significant bits (LEVEL1 and LEVEL2) of the least significant byte are used to indicate the
accuracy level of the tachometer reading. The accuracy ranges from most to least accurate.
[LEVEL1:LEVEL2]=11indicates a most accurate value, [LEVEL1:LEVEL2]=01 indicates the least accurate value
and [LEVEL1:LEVEL2]=00 is reserved for future use.
FF FFh indicates that the fan is not spinning, or that the tachometer input is not connected to a valid signal.
These registers are read only — a write to these registers has no effect.
When the LSByte of the LM96000 16-bit register is read, the other byte (MSByte) is latched at the current value
until it is read. At the end of the MSByte read the Fan Tachometer Reading registers are updated.
During spin-up, the PWM duty cycle reported is 0%.
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4.4 Register 30-32h: Current PWM Duty
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 0
(LSB)
Bit 1
Default
Value
30h
R/W
Fan1
Current
PWM
Duty
7
6
5
4
3
2
1
0
N/A
31h
R/W
Fan2
Current
PWM
Duty
7
6
5
4
3
2
1
0
N/A
32h
R/W
Fan3
Current
PWM
Duty
7
6
5
4
3
2
1
0
N/A
The Current PWM Duty registers store the current duty cycle at each PWM output. At initial power-on, the PWM
duty cycle is 100% and thus, when read, this register will return FFh. After the Ready/Lock/Start/Override register
Start bit is set, this register and the PWM signals will be updated based on the algorithm described in the Auto
Fan Control Operating Mode section.
When read, the Current PWM Duty registers return the current PWM duty cycle. These registers are read only
unless the fan is in manual (test) mode, in which case a write to these registers will directly control the PWM duty
cycle for each fan. The PWM duty cycle is represented as shown in the following table.
Current Duty
Value (Decimal)
Value (Hex)
0%
0
00h
0.3922%
1
01h
.
.
.
.
.
.
.
.
.
25.098%
64
40h
.
.
.
.
.
.
.
.
.
50.196%
128
80h
.
.
.
.
.
.
.
.
.
100%
255
FFh
4.5 Register 3Eh: Company ID
Register
Address
3Eh
Read/
Write
R
Register
Name
Bit 7
(MSB)
Company 7
ID
Bit 6
6
Bit 5
5
Bit 4
4
Bit 3
3
Bit 2
2
Bit 0
(LSB)
Bit 1
1
0
Default
Value
01h
The company ID register contains the company identification number. For Texas Instruments this is 01h. This
number is assigned by Intel and is a method for uniquely identifying the part manufacturer. This register is read
only — a write to this register has no effect.
4.6 Register 3Fh: Version/Stepping
Register
Address
3Fh
16
Read/
Write
R
Register
Name
Bit 7
(MSB)
Version/S VER3
tepping
Bit 6
VER2
Bit 5
VER1
Bit 4
VER0
Bit 3
STP3
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STP2
Bit 1
STP1
Bit 0
(LSB)
STP0
Default
Value
68h
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The four least significant bits of the Version/Stepping register [3.0] contain the current stepping of the LM96000
silicon. The four most significant bits [7.4] reflect the LM96000 base device number when set to a value of
0110b. For the LM96000, this register will read 01101000b (68h). Bit 3 of the stepping field is set to indicate that
the LM96000 is a super-set of the LM85 family of products.
The register is used by application software to identify which device in the hardware monitor family of ASICs has
been implemented in the given system. Based on this information, software can determine which registers to
read from and write to. Further, application software may use the current stepping to implement work-arounds for
bugs found in a specific silicon stepping.
This register is read only — a write to this register has no effect.
4.7 Register 40h: Ready/Lock/Start/Override
Register
Address
40h
Read/
Write
R/W
Bit
Register
Name
Bit 7
(MSB)
Ready/Lo RES
ck/Start/O
verride
Name
R/W
Bit 6
RES
Bit 5
RES
Bit 4
RES
Bit 3
Bit 2
OVRID
READY
Default
Bit 1
LOCK
Bit 0
(LSB)
START
Default
Value
00h
Description
0
START
R/W
0
When software writes a 1 to this bit, the LM96000 fan monitoring and PWM output control
functions will use the values set in the fan control limit and parameter registers (address
5Ch through 6Eh). Before this bit is set, the LM96000 will not update the used register
values, the default values will remain in effect. Whenever this bit is set to 0, the LM96000
fan monitoring and PWM output control functions use the default fan limits and
parameters, regardless of the current values in the limit and parameter registers (5C
through 6Eh). The LM96000 will preserve the values currently stored in the limit and
parameter registers when this bit is set or cleared. This bit is not effected by the state of
the Lock bit.
It is expected that all limit and parameter registers will be set by BIOS or application
software prior to setting this bit.
1
LOCK
R/W
0
Setting this bit to 1 locks specified limit and parameter registers. Once this bit is set, limit
and parameter registers become read only and will remain locked until the device is
powered off. This register bit becomes read only once it is set.
2
READY
R
0
The LM96000 sets this bit automatically after the part is fully powered up, has completed
the power-up-reset process, and after all A/D converters are properly functioning.
3
OVRID
R/W
4–7
Reserved
R
If this bit is set to 1, all PWM outputs will go to 100% duty cycle regardless of whether or
not the lock bit is set. The OVRID bit has precedence over the disabled mode. Therefore,
when OVRID is set the PWM will go to 100% even if the PWM is in the disabled mode.
0
Reserved
4.8 Register 41h: Interrupt Status Register 1
Register
Address
41h
Read/
Write
R
Register
Name
Interrupt
Status 1
Bit 7
(MSB)
ERR
Bit 6
ZN3
Bit 5
ZN2
Bit 4
ZN1
Bit 3
5V
Bit 2
3.3V
Bit 1
VCCP
Bit 0
(LSB)
2.5V
Default
Value
00h
The Interrupt Status Register 1 bits will be automatically set, by the LM96000, whenever a fault condition is
detected. A fault condition is detected whenever a measured value is outside the window set by its limit registers.
ZN3 and ZN1 bits will be set when a diode fault condition, such as a disconect or short, is detected. More than
one fault may be indicated in the interrupt register when read. This register will hold a set bit(s) until the event is
read by software. The contents of this register will be cleared (set to 0) automatically by the LM96000 after it is
read by software, if the fault condition is no longer exists. Once set, the Interrupt Status Register 1 bits will
remain set until a read event occurs, even if the fault condition no longer exists
This register is read only — a write to this register has no effect.
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Bit
Name
R/W
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Default
Description
0
2.5V_Error
R
0
The LM96000 automatically sets this bit to 1 when the 2.5V input voltage is less than
or equal to the limit set in the 2.5V Low Limit register or greater than the limit set in
the 2.5V High Limit register.
1
VCCP_Error
R
0
The LM96000 automatically sets this bit to 1 when the VCCP input voltage is less
than or equal to the limit set in the VCCP Low Limit register or greater than the limit
set in the VCCP High Limit register.
2
3.3V_Error
R
0
The LM96000 automatically sets this bit to 1 when the 3.3V input voltage is less than
or equal to the limit set in the 3.3V Low Limit register or greater than the limit set in
the 3.3V High Limit register.
3
5V_Error
R
0
The LM96000 automatically sets this bit to 1 when the 5V input voltage is less than or
equal to the limit set in the 5V Low Limit register or greater than the limit set in the 5V
High Limit register.
4
Zone 1 Limit
Exceeded
R
0
The LM96000 automatically sets this bit to 1 when the temperature input measured by
the Remote1− and Remote1+ inputs is less than or equal to the limit set in the
Processor (Zone1) Low Temp register or more than the limit set in the Processor
(Zone1) High Temp register. This bit will be set when a diode fault is detected.
5
Zone 2 Limit
Exceeded
R
0
The LM96000 automatically sets this bit to 1 when the temperature input measured by
the internal temperature sensor is less than or equal to the limit set in the Internal
(Zone2) Low Temp register or greater than the limit set in the Internal (Zone2) High
Temp register.
6
Zone 3 Limit
Exceeded
R
0
The LM96000 automatically sets this bit to 1 when the temperature input measured by
the Remote2− and Remote2+ inputs is less than or equal to the limit set in the
Internal (Zone2) Low Temp register or greater than the limit set in the Remote
(Zone3) High Temp register. This bit will be set when a diode fault is detected.
7
Error in Status
Register 2
R
0
If there is a set bit in Status Register 2, this bit will be set to 1.
4.9 Register 42h: Interrupt Status Register 2
Register
Address
42h
Read/
Write
R
Register
Name
Interrupt
Status
Register
2
Bit 7
(MSB)
ERR2
Bit 6
ERR1
Bit 5
FAN4
Bit 4
FAN3
Bit 3
FAN2
Bit 2
FAN1
Bit 1
RES
Bit 0
(LSB)
12V
Default
Value
00h
The Interrupt Status Register 2 bits will be automatically set, by the LM96000, whenever a fault condition is
detected. Interrupt Status Register 2 identifies faults caused by temperature sensor error, fan speed droping
below minimum set by the tachometer minimum register, the 12V input voltage going outside the window set by
its limit registers. Interrupt Status Register 2 will hold a set bit until the event is read by software. The contents of
this register will be cleared (set to 0) automatically by the LM96000 after it is ready by software, if fault condition
no longer exists. Once set, the Interrupt Status Register 2 bits will remain set until a read event occurs, even if
the fault no longer exists
This register is read only — a write to this register has no effect.
Bit
Name
R/W
Default
Description
0
+12V_Error
R
0
The LM96000 automatically sets this bit to 1 when the 12V input voltage either falls
below the limit set in the 12V Low Limit register or exceeds the limit set in the 12V
High Limit register.
1
Reserved
R
0
Reserved
2
Fan1 Stalled
R
0
The LM96000 automatically sets this bit to 1 when the TACH1 input reading is above
the value set in the Tach1 Minimum MSB and LSB registers.
3
Fan2 Stalled
R
0
The LM96000 automatically sets this bit to 1 when the TACH2 input reading is above
the value set in the Tach2 Minimum MSB and LSB registers.
4
Fan3 Stalled
R
0
The LM96000 automatically sets this bit to 1 when the TACH3 input reading is above
the value set in the Tach3 Minimum MSB and LSB registers.
5
Fan4 Stalled
R
0
The LM96000 automatically sets this bit to 1 when the TACH4 input reading is above
the value set in the Tach4 Minimum MSB and LSB registers.
18
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Bit
Name
R/W
Default
Description
6
Remote Diode 1
Fault
R
0
The LM96000 automatically sets this bit to 1 when there is either a short or open
circuit fault on the Remote1+ or Remote1− thermal diode input pins. A diode fault will
also set bit 4, Diode 1 Zone Limit bit, of Interrupt Status Register 1.
7
Remote Diode 2
Fault
R
0
The LM96000 automatically sets this bit to 1 when there is either a short or open
circuit fault on the Remote2+ or Remote2− thermal diode input pins. A diode fault will
also set bit 6, Diode 2 Zone Limit bit, of Interrupt Status Register 1.
4.10 Register 43h: VID
Register
Address
43h
Read/
Write
R
Register
Name
VID0–4
Bit 7
(MSB)
RES
Bit 6
RES
Bit 5
RES
Bit 4
VID4
Bit 3
VID3
Bit 2
VID2
Bit 0
(LSB)
Bit 1
VID1
Default
Value
VID0
The VID register contains the values of LM96000 VID0–VID4 input pins. This register indicates the status of the
VID lines that interconnect the processor to the Voltage Regulator Module (VRM). Software uses the information
in this register to determine the voltage that the processor is designed to operate at. With this information,
software can then dynamically determine the correct values to place in the VCCP Low Limit and VCCP High
Limit registers.
This register is read only — a write to this register has no effect.
4.11 Registers 44-4Dh: Voltage Limit Registers
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 0
(LSB)
Bit 1
Default
Value
44h
R/W
2.5V Low
Limit
7
6
5
4
3
2
1
0
00h
45h
R/W
2.5V High 7
Limit
6
5
4
3
2
1
0
FFh
46h
R/W
VCCP
Low Limit
7
6
5
4
3
2
1
0
00h
47h
R/W
VCCP
7
High Limit
6
5
4
3
2
1
0
FFh
48h
R/W
3.3V Low
Limit
7
6
5
4
3
2
1
0
00h
49h
R/W
3.3V High 7
Limit
6
5
4
3
2
1
0
FFh
4Ah
R/W
5V Low
Limit
7
6
5
4
3
2
1
0
00h
4Bh
R/W
5V High
Limit
7
6
5
4
3
2
1
0
FFh
4Ch
R/W
12V Low
Limit
7
6
5
4
3
2
1
0
00h
4Dh
R/W
12V High
Limit
7
6
5
4
3
2
1
0
FFh
If a voltage input either exceeds the value set in the voltage high limit register or falls below the value set in the
voltage low limit register, the corresponding bit will be set automatically by the LM96000 in the interrupt status
registers (41-42h). Voltages are presented in the registers at ¾ full scale for the nominal voltage, meaning that at
nominal voltage, each input will be C0h, as shown in Table 2.
Setting the Ready/Lock/Start/Override register Lock bit has no effect on these registers.
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Table 2. Voltage Limits vs Register Setting
Register Setting
at
Nominal Voltage
Nominal
Voltage
Input
Maximum
Voltage
Register Reading
at
Maximum
Voltage
Register Reading
at
Minimum
Voltage
Minimum
Voltage
2.5V
2.5V
C0h
3.32V
FFh
0V
00h
VCCP
2.25V
C0h
3.00V
FFh
0V
00h
3.3V
3.3V
C0h
4.38V
FFh
3.0V
AFh
5V
5.0V
C0h
6.64V
FFh
0V
00h
12V
12.0V
C0h
16.00V
FFh
0V
00h
4.12 Registers 4E-53h: Temperature Limit Registers
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 0
(LSB)
Bit 1
Default
Value
4Eh
R/W
Processo
r (Zone1)
Low
Temp
7
6
5
4
3
2
1
0
81h
4Fh
R/W
Processo
r (Zone1)
High
Temp
7
6
5
4
3
2
1
0
7Fh
50h
R/W
Processo
r (Zone2)
Low
Temp
7
6
5
4
3
2
1
0
81h
51h
R/W
Processo
r (Zone2)
High
Temp
7
6
5
4
3
2
1
0
7Fh
52h
R/W
Processo
r (Zone3)
Low
Temp
7
6
5
4
3
2
1
0
81h
53h
R/W
Processo
r (Zone3)
High
Temp
7
6
5
4
3
2
1
0
7Fh
If an external temperature input or the internal temperature sensor either exceeds the value set in the
corresponding high limit register or falls below the value set in the corresponding low limit register, the
corresponding bit will be set automatically by the LM96000 in the Interrupt Status Register 1 (41h). For example,
if the temperature read from the Remote1− and Remote1+ inputs exceeds the Processor (Zone1) High Temp
register limit setting, Interrupt Status Register 1 ZN1 bit will be set. The temperature limits in these registers are
represented as 8 bit, 2’s complement, signed numbers in Celsius, as shown below in Table 3.
Setting the Ready/Lock/Start/Override register Lock bit has no effect on these registers.
Table 3. Temperature Limits vs Register Settings
20
Temperature
Reading (Decimal)
Reading (Hex)
−127°C
−127
81h
.
.
.
.
.
.
.
.
.
−50°C
−50
CEh
.
.
.
.
.
.
.
.
.
0°C
0
00h
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Table 3. Temperature Limits vs Register Settings (continued)
Temperature
Reading (Decimal)
Reading (Hex)
.
.
.
.
.
.
.
.
.
50°C
50
32h
.
.
.
.
.
.
.
.
.
127°C
127
7Fh
4.13 Registers 54-5Bh: Fan Tachometer Low Limit
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 0
(LSB)
Bit 1
Default
Value
54h
55h
R/W
R/W
Tach1
Minimum
LSB
Tach1
Minimum
MSB
7
15
6
14
5
13
4
12
3
11
2
10
1
9
0
8
FFh
FFh
56h
57h
R/W
R/W
Tach2
Minimum
LSB
Tach2
Minimum
MSB
7
15
6
14
5
13
4
12
3
11
2
10
1
9
0
8
FFh
FFh
58h
59h
R/W
R/W
Tach3
Minimum
LSB
Tach3
Minimum
MSB
7
15
6
14
5
13
4
12
3
11
2
10
1
9
0
8
FFh
FFh
5Ah
5Bh
R/W
R/W
Tach4
Minimum
LSB
Tach4
Minimum
MSB
7
15
6
14
5
13
4
12
3
11
2
10
1
9
0
8
FFh
FFh
The Fan Tachometer Low Limit registers indicate the tachometer reading under which the corresponding bit will
be set in the Interrupt Status Register 2 register. In Auto Fan Control mode, the fan can run at low speeds, so
care should be taken in software to ensure that the limit is high enough not to cause sporadic alerts. The fan
tachometer will not cause a bit to be set in Interrupt Status Register 2 if the current value in Current PWM Duty
registers is 00h or if the fan 1 disabled via the Fan Configuration Register. Interrupts will never be generated for
a fan if its minimum is set to FF FFh.
Given the insignificance of Bit 0 and Bit 1, these bits could be programmed to remember which fan is which, as
follows.
Fan
Bit 1
Bit 0
CPU
0
0
Memory
0
1
Chassis Front
1
0
Chassis Rear
1
1
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Setting the Ready/Lock/Start/Override register Lock bit has no effect these registers.
4.14 Registers 5C-5Eh: Fan Configuration
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
Lock?
5Ch
R/W
Fan1
Configur
ation
ZON2
ZON1
ZON0
INV
RES
SPIN2
SPIN1
SPIN0
62h
✓
5Dh
R/W
Fan2
Configur
ation
ZON2
ZON1
ZON0
INV
RES
SPIN2
SPIN1
SPIN0
62h
✓
5Eh
R/W
Fan3
Configur
ation
ZON2
ZON1
ZON0
INV
RES
SPIN2
SPIN1
SPIN0
62h
✓
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further
attempts to write to this register shall have no effect. After power up the default value is used whenever the
Ready/Lock/Start/Override register Start bit is cleared even though modifications to this register are possible.
Bits [7:5] Zone/Mode
Bits [7:5] of the Fan Configuration registers associate each fan with a temperature sensor. When in Auto Fan
Mode the fan will be assigned to a zone, and its PWM duty cycle will be adjusted according to the temperature of
that zone. If ‘Hottest’ option is selected (101 or 110), the fan will be controlled by the hottest of zones 2 and 3, or
of zones 1, 2, and 3. To determine the ‘Hottest’ zone the PWM level for each zone is calculated then the the
highest PWM value is selected. When in manual control mode, the Current PWM duty registers (30h-32h)
become Read/Write. It is then possible to control the PWM outputs with software by writing to these registers.
When the fan is disabled (100) the corresponding PWM output should be driven low (or high, if inverted).
Zone 1: External Diode 1 (processor)
Zone 2: Internal Sensor
Zone 3: External Diode 2
Table 4. Fan Zone Setting
ZON[2:0]
Fan Configuration
000
Fan on zone 1 auto
001
Fan on zone 2 auto
010
Fan on zone 3 auto
011
Fan always on full
100
Fan disabled
101
Fan controlled by hottest of zones 2, 3
110
Fan controlled by hottest of zones 1, 2, 3
111
Fan manually controlled (Test Mode)
Bit [4] PWM Invert
Bit [4] inverts the PWM output. If set to 0, 100% duty cycle will yield an output that is always high. If set to 1,
100% duty cycle will yield an output that is always low.
Bit [3] Reserved
Bits [2:0] Spin Up
Bits [2:0] specify the ‘spin up’ time for the fan. When a fan is being started from a stationary state, the PWM
output is held at 100% duty cycle for the time specified in the Table 5 below before scaling to a lower speed.
22
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Table 5. Fan Spin-Up Register
SPIN[2:0]
Spin Up Time
000
0 sec
001
100 ms
010
250 ms
011
400 ms
100
700 ms
101
1000 ms
110
2000 ms
111
4000 ms
4.15 Registers 5F-61h: Auto Fan Speed Range, PWM Frequency
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 0
(LSB)
Bit 1
Default
Value
Lock?
5Fh
R/W
Zone1
Range/F
an1
Frequen
cy
RAN3
RAN2
RAN1
RAN0
HLFRQ
FRQ2
FRQ1
FRQ0
C4h
✓
60h
R/W
Zone2
Range/F
an2
Frequen
cy
RAN3
RAN2
RAN1
RAN0
HLFRQ
FRQ2
FRQ1
FRQ0
C4h
✓
61h
R/W
Zone3
Range/F
an3
Frequen
cy
RAN3
RAN2
RAN1
RAN0
HLFRQ
FRQ2
FRQ1
FRQ0
C4h
✓
In Auto Fan Mode, when the temperature for a zone is above the Temperature Limit (Registers 67-69h) and
below its Absolute Temperature Limit (Registers 6A-6Ch), the speed of a fan assigned to that zone is determined
as follows.
When the temperature reaches the Fan Temp Limit for a zone, the PWM output assigned to that zone will be
Fan PWM Minimum. Between Fan Temp Limit and (Fan Temp Limit + Range), the PWM duty cycle will increase
linearly according to the temperature as shown in Figure 9 below. The PWM duty cycle will be 100% at (Fan
Temp Limit + Range).
Cold
Fan Temp Limit - Hysteresis
Hysteresis is 0oC-15oC (6Dh-6Eh)
Zone n
Min PWM
or
OFF
Hot
Temperature
Fan Temp Limit
(67h-69h)
Fan Temp Limit +
Range
Absolute Limit
Range is 2oC to 80oC (5Fh-61h)
(6Ah-6Ch)
PWM duty cycle
linearly increasing as
temperature increases
PWM duty cycle linearly
deacreasing
as
decreasing as
temperature decreases
Zone n PWM set to Zone n PWM set to
Min FanSpeed (64h- Min FanSpeed (64h66h) 66h)
All Zones
100% PWM
Zone n
100% PWM
Figure 9. Fan Activity above Fan Temp Limit
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Example for PWM1 assigned to Zone 1:
•
– Zone 1 Fan Temp Limit (Register 67h) is set to 50°C (32h).
•
– Range (Register 5Fh) is set to 8°C (6xh).
•
– Fan 1 PWM Minimum (Register 64h) is set to 50% (32h).
In this case, the PWM1 duty cycle will be 50% at 50°C.
Since (Zone 1 Fan Temp Limit) + (Zone 1 Range) = 50°C + 8°C = 58°C, the fan will run at 100% duty cycle when
the temperature of the Zone 1 sensor reaches 58°C.
Since the midpoint of the fan control range is 54°C, and the median duty cycle is 75% (Halfway between the
PWM Minimum and 100%), PWM1 duty cycle would be 75% at 54°C.
Above (Zone 1 Fan Temp Limit) + (Zone 1 Range), the duty cycle will be 100%.
PWM frequency bits [3:0]
The PWM frequency bits [3:0] determine the PWM frequency for the fan.The LM96000 has high and low
frequency ranges for the PWM outputs, that are controlled by the HLFRQ bit.
PWM Frequency Selection (Default = 0011 = 30.04 Hz).
Table 6. Register Setting vs PWM Frequency
HLFRQ
Freq [2:0]
PWM Frequency
0
000
10.01 Hz
0
001
15.02 Hz
0
010
23.14 Hz
0
011
30.04 Hz
0
100
38.16 Hz
0
101
47.06 Hz
0
110
61.38 Hz
0
111
94.12 Hz
1
000
22.5 kHz
1
001
24 kHz
1
010
25.7 kHz
1
011
25.7 kHz
1
100
27.7 kHz
1
101
27.7 kHz
1
110
30 kHz
1
111
30 kHz
Range Selection RAN [3:0]
RAN [3:0]
Range (°C)
0000
2
0001
2.5
0010
3.33
0011
4
0100
5
0101
6.67
0110
8
0111
10
1000
13.33
1001
16
1010
20
1011
26.67
24
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RAN [3:0]
Range (°C)
1100
32
1101
40
1110
53.33
1111
80
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further
attempts to write to this register shall have no effect. After power up the default value is used whenever the
Ready/Lock/Start/Override register Start bit is cleared even though modifications to this register are possible.
4.16 Registers 62, 63h: Min/Off, Spike Smoothing
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
Lock?
62h
R/W
Min/Off,
Zone1
Spike
Smoothi
ng
OFF3
OFF2
OFF1
RES
ZN1E
ZN1-2
ZN1-1
ZN1-0
00h
✓
63h
R/W
Zone2,
Zone3
Spike
Smoothi
ng
ZN2E
ZN2-2
ZN2-1
ZN2-0
ZN3E
ZN3-2
ZN3-1
ZN3-0
00h
✓
The Off/Min Bits [7:5] specify whether the duty cycle will be 0% or Minimum Fan Duty when the measured
temperature falls below the Temperature LIMIT register setting (see table below). OFF1 applies to fan 1, OFF2
applies to fan 2, and OFF3 applies to fan 3.
If the Remote1 or Remote2 pins are connected to a processor or chipset, instantaneous temperature spikes may
be sampled by the LM96000. If these spikes are not ignored, the CPU fan (if connected to LM96000) may turn
on prematurely and produce unpleasant noise. For this reason, any zone that is connected to a chipset or
processor should have spike smoothing enabled.
When spike smoothing is enabled, the temperature reading registers will still reflect the current value of the
temperature — not the ‘smoothed out’ value.
ZN1E, ZN2E, and ZN3E enable temperature smoothing for zones 1, 2, and 3 respectively.
ZN1-2, ZN1-1, and ZN1-0 control smoothing time for Zone 1.
ZN2-2, ZN2-1, and ZN2-0 control smoothing time for Zone 2.
ZN3-2, ZN3-1, and ZN3-0 control smoothing time for Zone 3.
These registers become ready only when the Ready/Lock/Start/Override register Lock bit is set. Any further
attempts to write to these registers shall have no effect.
35 second Smoothing Filter
100
INPUT
80
INPUT
OUTPUT
60
40
OUTPUT
20
1.0
0.8
0.6
0.4
0.2
0
0
5
10
15
20
25
30
35
40
TIME (s)
Figure 10. What LM96000 Auto Fan Control Sees With and Without Spike Smoothing
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Table 7. Spike Smoothing
ZN-X[2:0]
Spike Smoothed Over
000
35 seconds
001
17.6 seconds
010
11.8 seconds
011
7.0 seconds
100
4.4 seconds
101
3.0 seconds
110
1.6 seconds
111
.8 seconds
Table 8. PWM Output Below Limit Depending on Value of Off/Min
Off/Min
PWM Action
0
At 0% duty below LIMIT
1
At Min PWM Duty below LIMIT
4.17 Registers 64-66h: Minimum PWM Duty Cycle
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 0
(LSB)
Bit 1
Default
Value
Lock?
64h
R/W
Fan1
7
PWM
Minimum
6
5
4
3
2
1
0
80h
✓
65h
R/W
Fan2
7
PWM
Minimum
6
5
4
3
2
1
0
80h
✓
66h
R/W
Fan3
7
PWM
Minimum
6
5
4
3
2
1
0
80h
✓
These registers specify the minimum duty cycle that the PWM will output when the measured temperature
reaches the Temperature LIMIT register setting.
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further
attempts to write to this register shall have no effect. After power up the default value is used whenever the
Ready/Lock/Start/Override register Start bit is cleared even though modifications to this register are possible.
Table 9. PWM Duty vs Register Setting for PWM Low Frequency Range
26
Current Duty
Value (Decimal)
Value (Hex)
0%
0
00h
0.3922%
1
01h
.
.
.
.
.
.
.
.
.
25.098%
64
40h
.
.
.
.
.
.
.
.
.
50.196%
128
80h
.
.
.
.
.
.
.
.
.
100%
255
FF
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PWM Duty Cycle vs Register Setting for PWM High Frequency Range
22.5KHz PWM Frequency
PWM Duty Cycle Level (%)
Value in Decimal
0.00
0
Value in Hex
0
6.25
1
-
15
01
-
0F
12.50
16
-
31
10
-
1F
18.75
32
-
47
20
-
2F
25.00
48
-
63
30
-
3F
31.25
64
-
79
40
-
4F
37.50
80
-
95
50
-
5F
43.75
96
-
111
60
-
6F
50.00
112
-
127
70
-
7F
56.25
128
-
143
80
-
8F
62.50
144
-
159
90
-
9F
68.75
160
-
175
A0
-
AF
75.00
176
-
191
B0
-
BF
81.25
192
-
207
C0
-
CF
87.50
208
-
223
D0
-
DF
93.75
224
-
239
E0
-
EF
100.00
240
-
255
F0
-
FF
24KHz PWM Frequency
PWM Duty Cycle Level (%)
Value in Decimal
0
Value in Hex
0
0
6.67
1
-
16
01
-
10
13.33
17
-
33
11
-
21
20.00
34
-
50
22
-
32
26.67
51
-
67
33
-
43
33.33
68
-
84
44
-
54
40.00
85
-
101
55
-
65
46.67
102
-
118
66
-
76
53.33
119
-
136
77
-
88
60.00
137
-
153
89
-
99
66.67
154
-
170
9A
-
AA
73.33
171
-
187
AB
-
BB
80.00
188
-
204
BC
-
CC
86.67
205
-
221
CD
-
DD
93.33
222
-
238
DE
-
EE
100.00
239
-
255
EF
-
FF
25.7KHz PWM Frequency
PWM Duty Cycle Level (%)
Value in Decimal
0
0
Value in Hex
0
7.14
1
-
17
01
-
11
14.29
18
-
36
12
-
24
21.43
37
-
54
25
-
36
28.57
55
-
72
37
-
48
35.71
73
-
90
49
-
5A
42.86
91
-
109
5B
-
6D
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25.7KHz PWM Frequency
PWM Duty Cycle Level (%)
Value in Decimal
Value in Hex
50.00
110
-
127
6E
-
7F
57.14
128
-
145
80
-
91
64.29
146
-
164
92
-
A4
71.43
165
-
182
A5
-
B6
78.57
183
-
200
B7
-
C8
85.71
201
-
218
C9
-
DA
92.86
219
-
237
DB
-
ED
100.00
238
-
255
EE
-
FF
27.7KHz PWM Frequency
PWM Duty Cycle Level (%)
Value in Decimal
0
Value in Hex
0
0
7.69
1
-
19
01
-
13
15.38
20
-
38
14
-
26
23.08
39
-
58
27
-
3A
30.77
59
-
78
3B
-
4E
38.46
79
-
97
4F
-
61
46.15
98
-
117
62
-
75
53.85
118
-
137
76
-
89
61.54
138
-
157
8A
-
9D
69.23
158
-
176
9E
-
B0
76.92
177
-
196
B1
-
C4
84.62
197
-
216
C5
-
D8
92.31
217
-
235
D9
-
EB
100.00
236
-
255
EC
-
FF
30KHz PWM Frequency
28
PWM Duty Cycle Level (%)
Value in Decimal
Value in Hex
0
0
0
8.33
1
-
20
01
-
14
16.67
21
-
42
15
-
2A
25.00
43
-
63
2B
-
3F
33.33
64
-
84
40
-
54
41.67
85
-
106
55
-
6A
50.00
107
-
127
6B
-
7F
58.33
128
-
148
80
-
94
66.67
149
-
170
95
-
AA
75.00
171
-
191
AB
-
BF
83.33
192
-
212
C0
-
D4
91.67
213
-
234
D5
-
EA
100.00
235
-
255
EB
-
FF
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4.18 Registers 67-69h: Temperature Limit
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 0
(LSB)
Bit 1
Default
Value
Lock?
67h
R/W
Zone1
Fan
Temp
Limit
7
6
5
4
3
2
1
0
5Ah
✓
68h
R/W
Zone2
Fan
Temp
Limit
7
6
5
4
3
2
1
0
5Ah
✓
69h
R/W
Zone3
Fan
Temp
Limit
7
6
5
4
3
2
1
0
5Ah
✓
These are the temperature limits for the individual zones. When the current temperature equals this limit, the fan
will be turned on if it is not already. When the temperature exceeds this limit, the fan speed will be increased
according to the algorithm set forth in the Auto Fan Range, PWM Frequency register description.
Default = 90°C = 5Ah
(1)
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further
attempts to write to this register shall have no effect. After power up the default value is used whenever the
Ready/Lock/Start/Override register Start bit is cleared even though modifications to this register are possible.
Table 10. Temperature Limit vs Register Setting
Temperature
Reading (Decimal)
Reading (Hex)
−127°C
−127
81h
.
.
.
.
.
.
.
.
.
−50°C
−50
CEh
.
.
.
.
.
.
.
.
.
0°C
0
00h
.
.
.
.
.
.
.
.
.
50°C
50
32h
.
.
.
.
.
.
.
.
.
127°C
127
7Fh
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4.19 Registers 6A-6Ch: Absolute Temperature Limit
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
Lock?
6Ah
R/W
Zone1
Absolute
Temp
Limit
7
6
5
4
3
2
1
0
64h
✓
6Bh
R/W
Zone2
Absolute
Temp
Limit
7
6
5
4
3
2
1
0
64h
✓
6Ch
R/W
Zone3
Absolute
Temp
Limit
7
6
5
4
3
2
1
0
64h
✓
In the Auto Fan mode, if a zone exceeds the temperature set in the Absolute Temperature Limit register, all of
the PWM outputs will incresase its duty cycle to 100%. This is a safety feature that attempts to cool the system if
there is a potentially catastrophic thermal event. If set to 80h (-128°C), the feature is disabled.
Default=100°C=64h
These registers become Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further
attempts to write to these registers shall have no effect. After power up the default values are used whenever the
Ready/Lock/Start/Override register Start bit is cleared even though modifications to these registers are possible.
Table 11. Absolute Limit vs Register Setting
Temperature
Reading (Decimal)
Reading (Hex)
−127°C
−127
81h
.
.
.
.
.
.
.
.
.
−50°C
−50
CEh
.
.
.
.
.
.
.
.
.
0°C
0
00h
.
.
.
.
.
.
.
.
.
50°C
50
32h
.
.
.
.
.
.
.
.
.
127°C
127
7Fh
4.20 Registers 6D-6Eh: Zone Hysteresis Registers
Register
Address
Read/
Write
Register
Name
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
Lock?
6Dh
R/W
Zone1
H1-3
and
Zone2
Hysteres
is
H1-2
H1-1
H1-0
H2-3
H2-2
H2-1
H2-0
44h
✓
6Eh
R/W
Zone3
H3-3
Hysteres
is
H3-2
H3-1
H3-0
RES
RES
RES
RES
40h
✓
30
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If the temperature is above Fan Temp Limit, then drops below Fan Temp Limit, the following will occur:
•
– The fan will remain on, at Fan PWM Minimum, until the temperature goes a certain amount below Fan
Temp Limit.
•
– The Hysteresis registers control this amount. See below table for details.
These registers become Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further
attempts to write to thses registers shall have no effect. After power up the default value is used whenever the
Ready/Lock/Start/Override register Start bit is cleared even though modifications to this register are possible.
Table 12. Hysteresis Settings
Setting
HYSTERESIS
0h
0°C
.
.
.
.
.
.
5h
5°C
.
.
.
.
.
.
Fh
15°C
4.21 Register 6Fh: Test Register
Register
Address
6Fh
Read/
Write
R/W
Register
Name
Test
Register
Bit 7
(MSB)
RES
Bit 6
RES
Bit 5
RES
Bit 4
Bit 3
RES
RES
Bit 2
RES
Bit 1
RES
Bit 0
(LSB)
XEN
Default
Value
00h
If the XEN bit is set high, the part will be placed into XOR tree test mode. Clearing the bit (writing a 0 to the XEN
bit) brings the part out of XOR tree test mode.
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further
attempts to write to this registers shall have no effect. After power up the default value is used whenever the
Ready/Lock/Start/Override register Start bit is cleared even though modifications to this register are possible.
4.22 Registers 70-7Fh: Vendor Specific Registers
These registers are for vendor specific features, including test registers. They will not default to a specific value
on power up.
4.22.1 Register 74h: Tachometer Monitor Mode
Register
Address
74h
Read/
Write
R/W
Register
Name
Tach
Monitor
Mode
Bit 7
(MSb)
RES
Bit 6
RES
Bit 5
Bit 4
T3/4-1
T3/4-0
Bit 3
T2-1
Bit 2
T2-0
Bit 1
T1-1
Bit 0
(LSb)
T1-0
Default
Value
Lock?
00h
Each fan TACH input has 4 possible modes of operation when using the low frequency range for the PWM
outputs. Mode 0 is the only mode that is available when using the high frequecy range for the PWM outputs. The
modes for TACH3 and TACH4 share control bits T3/4-[1:0]; TACH2 is controlled by T2-[1:0]; TACH1 is controlled
by T1-[1:0]. The result reported in all modes is based on 2 pulses per revolution. In order for modes 2 and 3 to
function properly it is required that the:
• PWM1 output must control the fan that has it's tachometer output connected to the TACH1 LM96000 input.
• PWM2 output must control the fan that has it's tachometer output connected to the TACH2 LM96000 input.
• PWM3 output must control the fans that have their tachometer outputs connected to the TACH3 or TACH4
LM96000 inputs.
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Setting (Tn[1:0])
Mode
00
0
Function
Traditional tach input monitor, false readings
when under minimum detctable RPM
01
1
Traditional tach input monitor, FFFFh reading
when under minimum detectable RPM
10
2
Most accurate readings, FFFFh reading
when under minimum detectable RPM
11
3
Least effect on programmed PWM of Fan,
FFFFh reading when under minimum
detectable RPM
•
Mode 0:
This mode uses the conventional method for fan tachometer pulse detection and does not include any circuitry to
compensate for PWM Fan drive. This mode should be used when PWM drive is not used to power the fan. This mode may
report a false RPM reading when under minimum detectable RPM as shown in the following table.
•
Mode 1:
This mode uses the conventional method for fan tach detection. The reading will be FFFFh if it is below minimum detectable
RPM.
•
Mode 2:
This mode is optimized for accurate RPM readings and activates circuitry that extends the lower side of the RPM reading as
shown in the following table.
•
Mode 3:
This mode minimizes the effect on the RPM setting and activates circuitry that extends the lower side of the RPM reading as
shown in the following table.
PWM Frequency
Mode 0 and 1 Minimum RPM
10.01
841
Mode 2 and 3 Minimum RPM
210
15.02
1262
315
23.14
1944
420
30.04
2523
420
38.16
3205
420
47.06
3953
420
61.38
5156
420
94.12
7906
420
This register is not effected when the Ready/Lock/Start/Override register Lock bit is set. After power up the
default value is used whenever the Ready/Lock/Start/Override register Start bit is cleared even though
modifications to this register are possible.
4.22.2 Register 75h: Fan Spin-up Mode
Register
Address
Read/
Write
75h
R/W
Register
Name
Fan
Spin-up
Mode
Bit 7
(MSB)
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
(LSB)
Default
Value
Lock?
RES
RES
RES
RES
RES
PWM3
SU
PWM2
SU
PWM1
SU
7h
✓
The PWM SU bit configures the PWM spin-up mode. If PWM SU is cleared the spin-up time will terminate after
time programmed by the Fan Configuration register has elapsed. When set to a 1, the spin-up time will terminate
early if the TACH reading exceeds the Tach Minimum value or after the time programmed by the Fan
Configuration register has elapsed, whichever occurs first.
This register becomes Read Only when the Ready/Lock/Start/Override register Lock bit is set. Any further
attempts to write to this register shall have no effect. After power up the default value is used whenever the
Ready/Lock/Start/Override register Start bit is cleared even though modifications to this register are possible.
4.23 Undefined Registers
Any reads to undefined registers will always return 00h. Writes to undefined registers will have no effect and will
not return an error.
32
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5.0 XOR TEST MODE
The LM96000 incorporates a XOR tree test mode. When the test mode is enabled by setting the “XEN” bit high
in the Test Register at address 6Fh via the SMBus, the part will enter XOR test mode.
Since the test mode an XOR tree, the order of the signals in the tree is not important. SMBDAT and SMBCLK
are not to be included in the test tree.
VID0
VID1
VID2
VID3
VID4
TACH1
TACH2
TACH3
TACH4
xTEST OUT
PWM2
PWM3
APPLICATIONS INFORMATION
+3.3V
470
100 pF
Pentium 4
PROCESSOR
6.2k
4.3k
REMOTE1+
REMOTE1-
REMOTE2+
REMOTE2-
MMBT3904
+12V
100 pF
TACH1
PWM1
TACH2
PWM2
+12V
6.8k
6.8k
.01
6.2k
+3.3V
470
PWM3
TACH3
4.3k
+12V
6.2k
4.3k
.01
6.8k
.01
TACH4
PROCESSOR
CORE VOLTAGE
VCCP_IN
2.5V SUPPLY
2.5V
12V SUPPLY
12V
5V SUPPLY
5V
3.3V
3.3V STBY
100 pF
0.1
GND
+3.3V
VID0
VID1
VID2
VID3
VID4
FROM
PROCESSOR
VRM
470
+12V
470
6.2k
SMBDAT
SMBCLK
LM96000
68
SMBus
(ICH or SIO Host)
68
4.3k
6.8k
.01
Figure 11. Typical Applications Schematic
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REVISION HISTORY
Changes from Revision B (March 2013) to Revision C
•
34
Page
Changed layout of National Data Sheet to TI format .......................................................................................................... 33
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PACKAGE OPTION ADDENDUM
www.ti.com
10-Dec-2020
PACKAGING INFORMATION
Orderable Device
Status
(1)
Package Type Package Pins Package
Drawing
Qty
Eco Plan
(2)
Lead finish/
Ball material
MSL Peak Temp
Op Temp (°C)
Device Marking
(3)
(4/5)
(6)
LM96000CIMT/NOPB
ACTIVE
TSSOP
PW
24
61
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 125
LM96000
CIMT
LM96000CIMTX/NOPB
ACTIVE
TSSOP
PW
24
2500
RoHS & Green
SN
Level-1-260C-UNLIM
0 to 125
LM96000
CIMT
(1)
The marketing status values are defined as follows:
ACTIVE: Product device recommended for new designs.
LIFEBUY: TI has announced that the device will be discontinued, and a lifetime-buy period is in effect.
NRND: Not recommended for new designs. Device is in production to support existing customers, but TI does not recommend using this part in a new design.
PREVIEW: Device has been announced but is not in production. Samples may or may not be available.
OBSOLETE: TI has discontinued the production of the device.
(2)
RoHS: TI defines "RoHS" to mean semiconductor products that are compliant with the current EU RoHS requirements for all 10 RoHS substances, including the requirement that RoHS substance
do not exceed 0.1% by weight in homogeneous materials. Where designed to be soldered at high temperatures, "RoHS" products are suitable for use in specified lead-free processes. TI may
reference these types of products as "Pb-Free".
RoHS Exempt: TI defines "RoHS Exempt" to mean products that contain lead but are compliant with EU RoHS pursuant to a specific EU RoHS exemption.
Green: TI defines "Green" to mean the content of Chlorine (Cl) and Bromine (Br) based flame retardants meet JS709B low halogen requirements of
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