LM93
Hardware Monitor with Integrated Fan Control for Server
Management
1.0 General Description
The LM93, hardware monitor, has a two wire digital interface
compatible with SMBus 2.0. Using an 8-bit
ADC, the
LM93 measures the temperature of two remote diode con-
nected transistors as well as its own die and 16 power supply
voltages.
To set fan speed, the LM93 has two PWM outputs that are
each controlled by up to four temperature zones. The fan-
control algorithm is lookup table based. The LM93 includes a
digital filter that can be invoked to smooth temperature read-
ings for better control of fan speed. The LM93 has four
tachometer inputs to measure fan speed. Limit and status
registers for all measured values are included.
The LM93 builds upon the functionality of previous mother-
board management ASICs and uses some of the LM85's
features (i.e. smart tachometer mode). It also adds measure-
ment and control support for dynamic Vccp monitoring and
PROCHOT. It is designed to monitor a dual processor Xeon
class motherboard with a minimum of external components.
2.0 Features
n
8-bit
ADC
n
Monitors 16 power supplies
n
Monitors 2 remote thermal diodes
n
Internal ambient temperature sensing
n
Programmable autonomous fan control based on
temperature readings with fan boost support
n
Fan control based on 13-step lookup table
n
Temperature reading digital filter
n
1.0C digital temperature sensor resolution
n
0.5C temperature resolution for fan control
n
2 PWM fan speed control outputs
n
4 fan tachometer inputs
n
Dual processor thermal throttling (PROCHOT)
monitoring
n
Dual dynamic VID monitoring (6 VIDs per processor)
n
8 general purpose I/Os:
-- 4 can be configured as fan tachometer inputs
-- 2 can be configured to connect to THERMTRIP from
a processor
-- 2 are standard GPIOs that could be used to monitor
IERR signal
n
2 general purpose inputs that can be used to monitor
SCSI termination signals
n
Limit register comparisons of all monitored values
n
2-wire, SMBus 2.0 compliant, serial digital interface
-- Supports byte/block read and write
-- Configurable slave address (tri-level pin selects 1 of
3 possible addresses)
n
2.5V reference voltage output
n
56-pin TSSOP package
n
XOR-tree test mode
3.0 Key Specifications
n
Voltage Measurement Accuracy
2% FS (max)
n
Resolution
8-bits, 1C
n
Temperature Sensor Accuracy
3C (max)
n
Temperature Range:
-- LM93 Operational
0C to +85C
-- Remote Temp Accuracy
0C to +125C
n
Power Supply Voltage
+3.0V to +3.6V
n
Power Supply Current
0.9 mA
4.0 Applications
n
Servers
n
Workstations
n
Multi-Microprocessor based equipment
5.0 Ordering Information
Order Number NS Package Number Transport media
LM93CIMT
MTD56
34 units in rail
LM93CIMTX
MTD56
1000 units in tape-and-reel
I2C is a registered trademark of the Philips Corporation.
April 2004
LM93
Hardware
Monitor
with
Integrated
Fan
Control
for
Server
Management
2004 National Semiconductor Corporation
DS200682
www.national.com
Table of Contents
1.0 General Description ..................................................................................................................................... 1
2.0 Features ....................................................................................................................................................... 1
3.0 Key Specifications ........................................................................................................................................ 1
4.0 Applications .................................................................................................................................................. 1
5.0 Ordering Information .................................................................................................................................... 1
6.0 Block Diagram .............................................................................................................................................. 2
7.0 Application .................................................................................................................................................... 3
8.0 Connection Diagram .................................................................................................................................... 7
9.0 Pin Descriptions ........................................................................................................................................... 8
10.0 Server Terminology .................................................................................................................................. 10
11.0 Recommended Implementation ................................................................................................................ 11
12.0 Functional Description .............................................................................................................................. 12
12.1 MONITORING CYCLE TIME ................................................................................................................ 12
12.2
A/D INHERENT AVERAGING .......................................................................................................... 12
12.3 TEMPERATURE MONITORING ........................................................................................................... 12
12.3.1 Temperature Data Format ............................................................................................................... 12
12.3.2 Thermal Diode Fault Status ............................................................................................................. 12
12.4 VOLTAGE MONITORING ...................................................................................................................... 12
12.5 RECOMMENDED EXTERNAL SCALING RESISTORS FOR +12V POWER RAILS .......................... 13
12.6 RECOMMENDED EXTERNAL SCALING CIRCUIT FOR -12V POWER INPUT ................................ 13
12.7 DYNAMIC Vccp MONITORING USING VID ......................................................................................... 15
12.8 V
REF
OUTPUT ....................................................................................................................................... 15
12.9 PROCHOT BACKGROUND INFORMATION ........................................................................................ 15
12.10 PROCHOT MONITORING .................................................................................................................. 16
12.11 PROCHOT OUTPUT CONTROL ........................................................................................................ 16
12.12 FAN SPEED MEASUREMENT ........................................................................................................... 17
12.13 SMART FAN SPEED MEASUREMENT ............................................................................................. 17
13.0 Inputs/Outputs .......................................................................................................................................... 17
13.1 ALERT OUTPUT ................................................................................................................................... 17
13.2 RESET INPUT/OUTPUT ....................................................................................................................... 17
13.3 PWM1 AND PWM2 OUTPUTS ............................................................................................................. 17
13.4 SCSI_TERMx INPUTS .......................................................................................................................... 17
13.5 VRD1_HOT AND VRD2_HOT INPUTS ................................................................................................ 18
13.6 GPIO PINS ............................................................................................................................................ 18
13.7 FAN TACH INPUTS ............................................................................................................................... 18
14.0 SMBus Interface ....................................................................................................................................... 18
14.1 SMBUS ADDRESSING ......................................................................................................................... 18
14.2 DIGITAL NOISE EFFECT ON SMBUS COMMUNICATION ................................................................. 18
14.3 GENERAL SMBUS TIMING .................................................................................................................. 18
14.4 SMBUS ERROR SAFETY FEATURES ................................................................................................ 19
14.5 SERIAL INTERFACE PROTOCOLS ..................................................................................................... 19
14.5.1 Address Incrementing ...................................................................................................................... 19
14.5.2 Block Command Code Summary .................................................................................................... 20
14.5.3 Write Operations
............................................................................................................................. 20
14.5.3.1 Write Byte ................................................................................................................................... 20
14.5.3.2 Write Word ................................................................................................................................. 20
14.5.3.3 SMBus Write Block to Any Address ........................................................................................... 21
14.5.3.4 I
2
C
TM
Block Write ....................................................................................................................... 21
14.5.4 Read Operations .............................................................................................................................. 22
14.5.4.1 Read Byte .................................................................................................................................. 22
14.5.4.2 Read Word ................................................................................................................................. 22
14.5.4.3 SMBus Block-Write Block-Read Process Call ........................................................................... 22
14.5.4.4 Simulated SMBus Block-Write Block-Read Process Call .......................................................... 24
14.5.4.5 SMBus Fixed Address Block Reads .......................................................................................... 24
14.5.4.6 I
2
C Block Reads ......................................................................................................................... 25
14.6 READING AND WRITING 16-BIT REGISTERS ................................................................................... 25
15.0 Using The LM93 ....................................................................................................................................... 26
15.1 POWER ON .......................................................................................................................................... 26
15.2 RESETS ................................................................................................................................................ 26
15.3 ADDRESS SELECTION ........................................................................................................................ 26
15.4 DEVICE SETUP .................................................................................................................................... 26
15.5 ROUND ROBIN VOLTAGE/TEMPERATURE CONVERSION CYCLE ................................................. 26
LM93
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Table of Contents
(Continued)
15.6 ERROR STATUS REGISTERS ............................................................................................................. 27
15.6.1 ASF Mode ........................................................................................................................................ 27
15.7 MASKING, ERROR STATUS AND ALERT ........................................................................................... 27
15.8 LAYOUT AND GROUNDING ................................................................................................................ 27
15.9 THERMAL DIODE APPLICATION ......................................................................................................... 27
15.9.1 Accuracy Effects of Diode Non-Ideality Factor ................................................................................ 28
15.9.2 PCB Layout for Minimizing Noise .................................................................................................... 28
15.10 FAN CONTROL ................................................................................................................................... 28
15.10.1 Automatic Fan Control Algorithm ................................................................................................... 28
15.10.2 Fan Control Temperature Resolution ............................................................................................ 30
15.10.3 Zone 1-4 to PWM1-2 Binding ........................................................................................................ 31
15.10.4 Fan Control Duty Cycles ............................................................................................................... 31
15.10.5 Alternate PWM Frequencies .......................................................................................................... 31
15.10.6 Fan Control Priorities ..................................................................................................................... 31
15.10.7 PWM to 100% Conditions ............................................................................................................. 31
15.10.8 VRDx_HOT Ramp-Up/Ramp-Down .............................................................................................. 32
15.10.9 PROCHOT Ramp-Up/Ramp-Down ............................................................................................... 32
15.10.10 Manual PWM Override ................................................................................................................ 32
15.10.11 Fan Spin-Up Control .................................................................................................................... 32
15.11 XOR TREE TEST ................................................................................................................................ 33
16.0 Registers .................................................................................................................................................. 34
16.1 REGISTER WARNINGS ....................................................................................................................... 34
16.2 REGISTER SUMMARY TABLE ............................................................................................................. 34
16.3 FACTORY REGISTERS 00h3Fh ........................................................................................................ 40
16.3.1 Register 00h
XOR Test ................................................................................................................. 40
16.3.2 Register 01h
SMBus Test ............................................................................................................. 40
16.3.3 Register 3Eh
Manufacturer ID ...................................................................................................... 40
16.3.4 Register 3Fh
Version/Stepping ..................................................................................................... 40
16.4 BMC ERROR STATUS REGISTERS 40h47h .................................................................................... 41
16.4.1 Register 40h
B_Error Status 1 ...................................................................................................... 41
16.4.2 Register 41h
B_Error Status 2 ...................................................................................................... 42
16.4.3 Register 42h
B_Error Status 3 ...................................................................................................... 42
16.4.4 Register 43h
B_Error Status 4 ...................................................................................................... 43
16.4.5 Register 44h
B_P1_PROCHOT Error Status ............................................................................... 43
16.4.6 Register 45h
B_P2_PROCHOT Error Status ............................................................................... 44
16.4.7 Register 46h
B_GPI Error Status .................................................................................................. 44
16.4.8 Register 47h
B_Fan Error Status .................................................................................................. 45
16.5 HOST ERROR STATUS REGISTERS .................................................................................................. 45
16.5.1 Register 48h
H_Error Status 1 ...................................................................................................... 45
16.5.2 Register 49h
H_Error Status 2 ...................................................................................................... 46
16.5.3 Register 4Ah
H_Error Status 3 ..................................................................................................... 47
16.5.4 Register 4Bh
H_Error Status 4 ..................................................................................................... 48
16.5.5 Register 4Ch
H_P1_PROCHOT Error Status ............................................................................... 49
16.5.6 Register 4Dh
B_P2_PROCHOT Error Status ............................................................................... 50
16.5.7 Register 4Eh
H_GPI Error Status ................................................................................................. 51
16.5.8 Register 4Fh
H_Fan Error Status ................................................................................................. 52
16.6 VALUE REGISTERS ............................................................................................................................. 52
16.6.1 Registers 5053h
Unfiltered Temperature Value Registers ......................................................... 52
16.6.2 Registers 5455h
Filtered Temperature Value Registers ............................................................. 52
16.6.3 Register 5665h
A/D Channel Voltage Registers ........................................................................ 53
16.6.4 Register 67h
Current P1_PROCHOT ........................................................................................... 53
16.6.5 Register 68h
Average P1_PROCHOT .......................................................................................... 54
16.6.6 Register 69h
Current P2_PROCHOT ........................................................................................... 54
16.6.7 Register 6Ah
Average P2_PROCHOT ......................................................................................... 54
16.6.8 Register 6Bh
GPI State ................................................................................................................. 55
16.6.9 Register 6Ch
P1_VID .................................................................................................................... 55
16.6.10 Register 6Dh
P2_VID .................................................................................................................. 55
16.6.11 Register 6E75h
Fan Tachometer Readings .............................................................................. 56
16.7 LIMIT REGISTERS ................................................................................................................................ 57
16.7.1 Registers 787Fh
Temperature Limit Registers ........................................................................... 57
16.7.2 Registers 8083h
Fan Boost Temperature Registers .................................................................. 57
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