Rainbow Electronics LM93 - Manual (Page 4)

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
Σ∆ 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 ™ 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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