EMC2305 Datasheet. Www.s Manuals.com. Smsc
User Manual: Marking of electronic components, SMD Codes 23, 23-, 2302, 2305-1, 2306, 2306A, 2306D**, 231*, 2310, 2311, 233*, 234*, 238*, 23T, 23W, 23p, 23t. Datasheets BF547, CM1213A-01SO, CM1213A-02SO, CM1213A-04SO, DTC143ECA, DTC143EUA, EMC2305-1, ESD4238, MTA90N03ZN3, MTN2302N3, MTN2306AN3, MTN2310N3, MTP2311N3, PAM2306D, TK71523AS.
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EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans PRODUCT FEATURES Datasheet General Description Features The EMC2305 is an SMBus compliant fan controller with up to five independently controlled PWM fan drivers. Each fan driver is controlled by a programmable frequency PWM driver and Fan Speed Control algorithm that operates in either a closed loop fashion or as a directly PWM-controlled device. The closed loop Fan Speed Control algorithm (FSC) has the capability to detect aging fans and alert the system. It will likewise detect stalled or locked fans and trigger an interrupt. Additionally, the EMC2305 offers a clock output so that multiple devices may be chained and slaved to the same clock source for optimal performance in large distributed systems. Applications Servers Projectors Industrial and Networking Equipment Notebook Computers Five Programmable Fan Control circuits (EMC2305) — — — — — — — 4-wire fan compatible High speed PWM (26 kHz) Low speed PWM (9.5Hz - 2240 Hz) Optional detection of aging fans Fan Spin Up Control and Ramp Rate Control Alert on Fan Stall Up to 3 Selectable Default Fan Speeds Watchdog Timer RPM-based fan control algorithm — 0.5% accuracy from 500 RPM to 16k RPM (external crystal oscillator) — 1% accuracy from 500 RPM to 16k RPM (internal clock) SMBus 2.0 Compliant — Up to 6 selectable SMBus addresses — SMBus Alert compatible CLK Pin can provide a clock source output Available in a 16-pin 4mm x 4mm QFN Lead-free RoHS Compliant package Block Diagram CLK TACH1 TACH2 TACH3 Tach Measurement TACH4 Tachometer Limit Registers TACH5 PWM1 Fan Speed Control Algorithm Fan Speed Control Algorithm PWM2 PWM3 PWM Drivers SMCLK SMDATA ALERT# Fan Speed Control Algorithm PWM4 Fan Speed Control Algorithm PWM5 Fan Speed Control Algorithm SMSC EMC2305 ADDR_SEL SMBus Slave Protocol DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Order Number: ORDERING NUMBER EMC2305-1-AP-TR PACKAGE FEATURES 16-pin QFN (Lead-free RoHS compliant) Five RPM-based fan speed control algorithms This product meets the halogen maximum concentration values per IEC61249-2-21 For RoHS compliance and environmental information, please visit www.smsc.com/rohs 80 ARKAY DRIVE, HAUPPAUGE, NY 11788 (631) 435-6000 or 1 (800) 443-SEMI Copyright © 2011 SMSC or its subsidiaries. All rights reserved. Circuit diagrams and other information relating to SMSC products are included as a means of illustrating typical applications. Consequently, complete information sufficient for construction purposes is not necessarily given. Although the information has been checked and is believed to be accurate, no responsibility is assumed for inaccuracies. SMSC reserves the right to make changes to specifications and product descriptions at any time without notice. Contact your local SMSC sales office to obtain the latest specifications before placing your product order. The provision of this information does not convey to the purchaser of the described semiconductor devices any licenses under any patent rights or other intellectual property rights of SMSC or others. All sales are expressly conditional on your agreement to the terms and conditions of the most recently dated version of SMSC's standard Terms of Sale Agreement dated before the date of your order (the "Terms of Sale Agreement"). The product may contain design defects or errors known as anomalies which may cause the product's functions to deviate from published specifications. Anomaly sheets are available upon request. SMSC products are not designed, intended, authorized or warranted for use in any life support or other application where product failure could cause or contribute to personal injury or severe property damage. Any and all such uses without prior written approval of an Officer of SMSC and further testing and/or modification will be fully at the risk of the customer. Copies of this document or other SMSC literature, as well as the Terms of Sale Agreement, may be obtained by visiting SMSC’s website at http://www.smsc.com. SMSC is a registered trademark of Standard Microsystems Corporation (“SMSC”). Product names and company names are the trademarks of their respective holders. SMSC DISCLAIMS AND EXCLUDES ANY AND ALL WARRANTIES, INCLUDING WITHOUT LIMITATION ANY AND ALL IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, TITLE, AND AGAINST INFRINGEMENT AND THE LIKE, AND ANY AND ALL WARRANTIES ARISING FROM ANY COURSE OF DEALING OR USAGE OF TRADE. IN NO EVENT SHALL SMSC BE LIABLE FOR ANY DIRECT, INCIDENTAL, INDIRECT, SPECIAL, PUNITIVE, OR CONSEQUENTIAL DAMAGES; OR FOR LOST DATA, PROFITS, SAVINGS OR REVENUES OF ANY KIND; REGARDLESS OF THE FORM OF ACTION, WHETHER BASED ON CONTRACT; TORT; NEGLIGENCE OF SMSC OR OTHERS; STRICT LIABILITY; BREACH OF WARRANTY; OR OTHERWISE; WHETHER OR NOT ANY REMEDY OF BUYER IS HELD TO HAVE FAILED OF ITS ESSENTIAL PURPOSE, AND WHETHER OR NOT SMSC HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Revision 1.3 (05-18-11) 2 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table of Contents Chapter 1 Pin Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Chapter 2 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 2.1 2.2 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 SMBus Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Chapter 3 Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 3.1 3.2 System Management Bus Interface Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.1 SMBus Start Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.2 SMBus Address and RD / WR Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.3 SMBus Data Bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.4 SMBus ACK and NACK Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.5 SMBus Stop Bit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.6 SMBus Time-out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.1.7 SMBus and I2C Compliance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SMBus Protocols . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.1 Write Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.2 Read Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.3 Send Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.4 Receive Byte . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.5 Block Write Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.6 Block Read Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.2.7 Alert Response Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 13 13 14 14 14 14 14 15 15 15 15 16 16 16 16 Chapter 4 Product Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Fan Control Modes of Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWM Fan Driver . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . RPM-based Fan Speed Control Algorithm (FSC). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.3.1 Programming the RPM-based Fan Speed Control Algorithm . . . . . . . . . . . . . . . . . . . . . Tachometer Measurement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4.1 Stalled Fan . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.4.2 Aging Fan or Invalid Drive Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . CLK Pin. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.1 Pull Up Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.2 External Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.5.3 Internal Clock. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Spin Up Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.6.1 Power Up Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ramp Rate Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Watchdog Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8.1 Power Up Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.8.2 Continuous Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 19 19 20 20 21 21 21 21 22 22 22 23 23 24 24 25 Chapter 5 Register Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 5.1 5.2 5.3 Register Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1.1 Lock Entries . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fan Status Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.1 Fan Status - 24h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.2 Fan Stall Status - 25h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . SMSC EMC2305 3 DATASHEET 26 31 31 32 32 33 Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 5.4 5.5 5.6 5.7 5.8 5.9 5.10 5.11 5.12 5.13 5.14 5.15 5.16 5.17 5.18 5.19 5.20 5.21 5.22 5.23 5.3.3 Fan Spin Status - 26h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.3.4 Fan Drive Fail Status - 27h . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fan Interrupt Enable Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWM Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5.1 PWM Polarity Config - 2Ah . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.5.2 PWM Output Config - 2Bh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWM Base Frequency Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6.1 PWM Base Frequency 1 - 2Bh . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.6.2 PWM Base Frequency 2 - 2Ch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fan Setting Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . PWM Divide Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fan Configuration 1 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fan Configuration 2 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Gain Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fan Spin Up Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fan Max Step Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fan Minimum Drive Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Valid TACH Count Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Fan Drive Fail Band Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TACH Target Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . TACH Reading Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Software Lock Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Product Features Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Product ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Manufacturer ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Revision Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 33 33 34 34 34 35 35 35 36 36 37 38 40 41 43 44 44 45 46 47 48 48 49 50 50 Chapter 6 Typical Operating Curves. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51 Chapter 7 Package Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 7.1 7.2 EMC2305 Package Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Package Markings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 Chapter 8 Datasheet Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Revision 1.3 (05-18-11) 4 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet List of Figures Figure 1.1 Figure 3.1 Figure 4.1 Figure 4.2 Figure 4.3 Figure 7.1 Figure 7.2 Figure 7.3 Figure 7.4 EMC2305 Pin Diagram (16-Pin QFN) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 SMBus Timing Diagram . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13 System Diagram of EMC2305 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18 Spin Up Routine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23 Ramp Rate Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24 Package Drawing - 16-Pin QFN 4mm x 4mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53 Package Dimensions - 16-Pin QFN 4mm x 4mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 PCB Footprint - 16-Pin QFN 4mm x 4mm . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54 EMC2305 Package Markings. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55 SMSC EMC2305 5 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet List of Tables Table 1.1 Pin Description for EMC2305 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 Table 1.2 Pin Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 Table 2.1 Absolute Maximum Ratings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Table 2.2 Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 Table 2.3 SMBus Electrical Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 Table 3.1 ADDR_SEL Pin Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14 Table 3.2 Protocol Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 3.3 Write Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 3.4 Read Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 3.5 Send Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15 Table 3.6 Receive Byte Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Table 3.7 Block Write Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Table 3.8 Block Read Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16 Table 3.9 Alert Response Address Protocol . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17 Table 4.1 Fan Controls Active for Operating Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19 Table 4.2 CLK Pin Pull-Up Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 Table 5.1 EMC2305 Register Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26 Table 5.2 Configuration Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31 Table 5.3 Fan Status Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Table 5.4 Fan Interrupt Enable Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33 Table 5.5 PWM Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34 Table 5.6 PWM Base Frequency Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Table 5.7 PWM_BASEx[1:0] Bit Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 35 Table 5.8 Fan Driver Setting Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Table 5.9 PWM Divide Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36 Table 5.10 Fan Configuration 1 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Table 5.11 Range Decode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37 Table 5.12 Minimum Edges for Fan Rotation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Table 5.13 Update Time . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Table 5.14 Fan Configuration 2 Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38 Table 5.15 Derivative Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39 Table 5.16 Error Range Options . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Table 5.17 Gain Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40 Table 5.18 Gain Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Table 5.19 Fan Spin Up Configuration Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Table 5.20 DRIVE_FAIL_CNT[1:0] Bit Decode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41 Table 5.21 Spin Level . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42 Table 5.22 Spin Time. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Table 5.23 Fan Max Step Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43 Table 5.24 Minimum Fan Drive Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Table 5.25 Valid TACH Count Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44 Table 5.26 Fan Drive Fail Band Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45 Table 5.27 TACH Target Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46 Table 5.28 TACH Reading Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47 Table 5.29 Software Lock Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Table 5.30 Product Features Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48 Table 5.31 ADDR_SEL Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Table 5.32 FAN_SPD Pin Configuration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Table 5.33 Product ID Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49 Table 5.34 Manufacturer ID Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Table 5.35 Revision Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50 Table 8.1 Customer Revision History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56 Revision 1.3 (05-18-11) 6 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 13 PWM4 14 TACH4 15 PWM5 16 TACH5 Chapter 1 Pin Description SMDATA 1 SMCLK 2 VDD 3 12 ALERT# EMC2305 16-QFN 11 CLK 10 TACH3 ADDR_SEL 4 5 6 7 8 PWM1 TACH1 PWM2 TACH2 9 PWM3 Figure 1.1 EMC2305 Pin Diagram (16-Pin QFN) Table 1.1 Pin Description for EMC2305 PIN NUMBER PIN NAME PIN FUNCTION PIN TYPE 1 SMDATA SMBus data input/output - requires external pull-up resistor DIOD (5V) 2 SMCLK SMBus clock input - requires external pull-up resistor DI (5V) 3 VDD Power Supply Power 4 ADDR_SEL Address selection input - requires pull-up resistor AIO SMSC EMC2305 7 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 1.1 Pin Description for EMC2305 (continued) PIN NUMBER PIN NAME 5 PWM1 6 TACH1 7 PWM2 8 TACH2 9 PWM3 10 TACH3 11 CLK 12 ALERT# 13 PWM4 14 TACH4 15 PWM5 PIN FUNCTION PIN TYPE Push-Pull PWM output driver for Fan 1 DO Open Drain PWM output driver for Fan 1 OD (5V) Open drain tachometer input for Fan 1requires pull-up resistor DI (5V) Push-Pull PWM output driver for Fan 2 DO Open Drain PWM output driver for Fan 2 OD (5V) Open drain tachometer input for Fan 2 requires pull-up resistor DI (5V) Push-Pull PWM output driver for Fan 3 DO Open Drain PWM output driver for Fan 3 OD (5V) Open drain tachometer input for Fan 3 requires pull-up resistor DI (5V) Clock input for tachometer measurement DI (5V) Push Pull Clock output to other fan controllers to synchronize Fan Speed Control DO Active low interrupt - requires external pull-up resistor. OD (5V) Push-Pull PWM output driver for Fan 4 DO Open Drain PWM output driver for Fan 4 OD (5V) Open drain tachometer input for Fan 4 requires pull-up resistor DI (5V) Push-Pull PWM output driver for Fan 5 DO Open Drain PWM output driver for Fan 5 OD (5V) 16 TACH5 Open drain tachometer input for Fan 5 requires pull-up resistor DI (5V) Bottom Pad GND Ground Power The pin types are described in detail below. All pins labeled with (5V) are 5V tolerant. APPLICATION NOTE: For the 5V tolerant pins that have a pull-up resistor, the voltage difference between VDD and the 5V tolerant pad must never be more than 3.6V. Revision 1.3 (05-18-11) 8 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 1.2 Pin Types SMSC EMC2305 PIN TYPE DESCRIPTION Power This pin is used to supply power or ground to the device. AIO Analog input / output - this pin is used for analog signals DI Digital Input - this pin is used as a digital input. This pin is 5V tolerant. DO Push / Pull Digital Output - this pin is used as a digital output. It can both source and sink current. DIOD Digital Input / Open Drain Output this pin is used as a digital I/O. When it is used as an output, it is open drain and requires a pull-up resistor. This pin is 5V tolerant. OD Open Drain Digital Output - this pin is used as a digital output. It is open drain and requires a pull-up resistor. This pin is 5V tolerant. 9 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Chapter 2 Electrical Specifications Table 2.1 Absolute Maximum Ratings Voltage on 5V tolerant pins (V5VT_pin) -0.3 to 5.5 V Voltage on 5V tolerant pins (|V5VT_pin - VDD|) (see Note 2.1) 0 to 3.6 V Voltage on VDD pin -0.3 to 4 V Voltage on any other pin to GND -0.3 to VDD + 0.3 V Package Thermal Resistance - Junction to Ambient (θJA) 40 °C/W Operating Ambient Temperature Range -40 to 125 °C Storage Temperature Range -55 to 150 °C ESD Rating, All Pins, HBM 2000 V Note: Stresses above those listed could cause permanent damage to the device. This is a stress rating only and functional operation of the device at any other condition above those indicated in the operation sections of this specification is not implied. Note 2.1 2.1 For the 5V tolerant pins that have a pull-up resistor, the pull-up voltage must not exceed 3.6V when the EMC2305 is unpowered. Electrical Specifications Table 2.2 Electrical Specifications VDD = 3V to 3.6V, TA = -40°C to 125°C, all Typical values at TA = 27°C unless otherwise noted. CHARACTERISTIC SYMBOL MIN TYP MAX UNIT 3.3 3.6 V 625 800 uA CONDITIONS DC Power Supply Voltage VDD Supply Current IDD 3 PWM Fan Driver PWM Resolution PWM PWM Duty Cycle DUTY 256 Steps 0 100 % RPM-based Fan Controller Tachometer Range Tachometer Setting Accuracy Input High Voltage Revision 1.3 (05-18-11) TACH ΔTACH 480 ΔTACH VIH 16000 RPM ±0.5 ±1 % External oscillator 32.768kHz ±1 ±2 % Internal Oscillator 2.0 V 10 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 2.2 Electrical Specifications (continued) VDD = 3V to 3.6V, TA = -40°C to 125°C, all Typical values at TA = 27°C unless otherwise noted. CHARACTERISTIC SYMBOL Input Low Voltage VIL Output High Voltage Output Low Voltage MIN TYP MAX UNIT 0.8 V VDD 0.4 VOH 8 mA current drive V VOL 0.4 V 8 mA current sink ILEAK ±5 uA ALERT# pin Powered and unpowered 0°C < TA < 85°C pull-up voltage < 3.6V Leakage current Note 2.2 2.2 CONDITIONS All voltages are relative to ground. SMBus Electrical Specifications Table 2.3 SMBus Electrical Specifications VDD= 3V to 3.6V, TA = -40°C to 125°C Typical values are at TA = 27°C unless otherwise noted. CHARACTERISTIC SYMBOL MIN TYP MAX UNITS CONDITIONS SMBus Interface Input High Voltage VIH Input Low Voltage VIL Output High Voltage Output Low Voltage Input High/Low Current Input Capacitance VOH 2.0 V 0.8 VDD - 0.4 V V VOL 0.4 V 4 mA current sink IIH / IIL ±5 uA Powered and unpowered 0°C < TA < 85°C CIN 5 pF SMBus Timing Clock Frequency fSMB 10 400 kHz 50 ns Spike Suppression tSP Bus free time Start to Stop tBUF 1.3 us Setup Time: Start tSU:STA 0.6 us Setup Time: Stop tSU:STP 0.6 us Data Hold Time tHD:DAT 0 us Data Setup Time tSU:DAT 0.6 us SMSC EMC2305 11 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 2.3 SMBus Electrical Specifications (continued) VDD= 3V to 3.6V, TA = -40°C to 125°C Typical values are at TA = 27°C unless otherwise noted. CHARACTERISTIC SYMBOL MIN Clock Low Period tLOW 1.3 us Clock High Period tHIGH 0.6 us Clock/Data Fall time tFALL 300 ns Min = 20+0.1CLOAD ns Clock/Data Rise time tRISE 300 ns Min = 20+0.1CLOAD ns CLOAD 400 pF per bus line Capacitive Load Revision 1.3 (05-18-11) TYP MAX 12 DATASHEET UNITS CONDITIONS SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Chapter 3 Communications 3.1 System Management Bus Interface Protocol The EMC2305 communicates with a host controller, such as an SMSC SIO, through the SMBus. The SMBus is a two-wire serial communication protocol between a computer host and its peripheral devices. A detailed timing diagram is shown in Figure 3.1. Stretching of the SMCLK signal is supported; however, the EMC2305 will not stretch the clock signal. TLOW THIGH THD:STA TSU:STO TRISE SMCLK THD:STA TFALL THD:DAT TSU:STA TSU:DAT SMDATA TBUF P S S S - Start Condition P - Stop Condition P Figure 3.1 SMBus Timing Diagram 3.1.1 SMBus Start Bit The SMBus Start bit is defined as a transition of the SMBus Data line from a logic ‘1’ state to a logic ‘0’ state while the SMBus Clock line is in a logic ‘1’ state. 3.1.2 SMBus Address and RD / WR Bit The SMBus Address Byte consists of the 7-bit client address followed by a RD / WR indicator bit. If this RD / WR bit is a logic ‘0’, then the SMBus Host is writing data to the client device. If this RD / WR bit is a logic ‘1’, then the SMBus Host is reading data from the client device. The SMBus client will respond to one of multiple SMBus addresses determined by the pull-up resistor on the ADDR_SEL pin. The ADDR_SEL pin decodes one of six pull-up resistors upon device power up. Depending on the resistor used, the CLK pin may also be used to select additional functionality. SMSC EMC2305 13 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 3.1 ADDR_SEL Pin Decode PULL-UP RESISTOR 3.1.3 SMBUS ADDRESS 4.7k Ohm ±5% 0101_110(r/w) 6.8k Ohm ±5% 0101_111(r/w) 10k Ohm ±5% 0101_100(r/w) 15k Ohm ±5% 0101_101(r/w) 22k Ohm ±5% 1001_100(r/w) 33k Ohm ±5% 1001_101(r/w) ADDITIONAL FUNCTIONS None - CLK pin used as clock input or output CLK pin used to determine default fan drive - see Section 4.5.1. The CLK pin cannot be used as a clock input or output SMBus Data Bytes All SMBus Data bytes are sent most significant bit first and composed of 8-bits of information. 3.1.4 SMBus ACK and NACK Bits The SMBus client will acknowledge all data bytes that it receives (as well as the client address if it matches and the ARA address if the ALERT# pin is asserted). This is done by the client device pulling the SMBus Data line low after the 8th bit of each byte that is transmitted. The Host will NACK (not acknowledge) the data received from the client by holding the SMBus data line high after the 8th data bit has been sent. 3.1.5 SMBus Stop Bit The SMBus Stop bit is defined as a transition of the SMBus Data line from a logic ‘0’ state to a logic ‘1’ state while the SMBus clock line is in a logic ‘1’ state. When the EMC2305 detects an SMBus Stop bit has been communicating with the SMBus protocol, it will reset its client interface and prepare to receive further communications. 3.1.6 SMBus Time-out The EMC2305 includes an SMBus timeout feature. Following a 30ms period of inactivity on the SMBus, the device will time-out and reset the SMBus interface. The SMBus timeout feature is disabled by default and can be enabled via clearing the DIS_TO bit in the Configuration register (20h). 3.1.7 SMBus and I2C Compliance The major difference between SMBus and I2C devices is highlighted here. For complete compliance information refer to the SMBus 2.0 specification. 1. Minimum frequency for SMBus communications is 10kHz (I2C has no minimum frequency). 2. The slave protocol will reset if the clock is held low for longer than 30ms (I2C has no timeout). 3. The slave protocol will reset if both the clock and data lines are held high for longer than 150us. 4. I2C devices do not support the Alert Response Address functionality (which is optional for SMBus). Revision 1.3 (05-18-11) 14 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 5. The Block Read and Block Write protocols are only compliant with I2C data formatting. They do not support SMBus formatting for Block Read and Block Write protocols. 3.2 SMBus Protocols The EMC2305 is SMBus 2.0 compatible and supports Send Byte, Read Byte, Receive Byte and Write Byte as valid protocols as shown below. It will respond to the Alert Response Address protocol but is not in full compliance. All of the below protocols use the convention in Table 3.2. When reading the protocol blocks, the value of YYYY_YYYb should be replaced with the respective SMBus addresses. Table 3.2 Protocol Format DATA SENT TO DEVICE DATA SENT TO THE HOST # of bits sent 3.2.1 # of bits sent Write Byte The Write Byte is used to write one byte of data to the registers as shown below Table 3.3. Table 3.3 Write Byte Protocol START SLAVE ADDRESS WR ACK REGISTER ADDRESS ACK REGISTER DATA ACK STOP 1 -> 0 YYYY_YYYb 0 0 XXh 0 XXh 0 0 -> 1 3.2.2 Read Byte The Read Byte protocol is used to read one byte of data from the registers as shown in Table 3.4. Table 3.4 Read Byte Protocol START SLAVE ADDRESS WR ACK Register Address ACK START Slave Address RD ACK Register Data NACK STOP 1 -> 0 YYYY_YYYb 0 0 XXh 0 0 -> 1 YYYY_YYYb 1 0 XXh 1 0 -> 1 3.2.3 Send Byte The Send Byte protocol is used to set the internal address register pointer to the correct address location. No data is transferred during the Send Byte protocol as shown in Table 3.5. Table 3.5 Send Byte Protocol START SLAVE ADDRESS WR ACK REGISTER ADDRESS ACK STOP 1 -> 0 YYYY_YYYb 0 0 XXh 0 0 -> 1 SMSC EMC2305 15 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 3.2.4 Receive Byte The Receive Byte protocol is used to read data from a register when the internal register address pointer is known to be at the right location (e.g. set via Send Byte). This is used for consecutive reads of the same register as shown in Table 3.6. Table 3.6 Receive Byte Protocol START SLAVE ADDRESS RD ACK REGISTER DATA NACK STOP 1 -> 0 YYYY_YYYb 1 0 XXh 1 0 -> 1 3.2.5 Block Write Protocol The Block Write is used to write multiple data bytes to a group of contiguous registers as shown in Table 3.7. It is an extension of the Write Byte Protocol. Table 3.7 Block Write Protocol START SLAVE ADDRESS WR ACK REGISTER ADDRESS ACK REGISTER DATA ACK 1 ->0 YYYY_YYYb 0 0 XXh 0 XXh 0 REGISTER DATA ACK REGISTER DATA ACK ... REGISTER DATA ACK STOP XXh 0 XXh 0 ... XXh 0 0 -> 1 3.2.6 Block Read Protocol The Block Read is used to read multiple data bytes from a group of contiguous registers as shown in Table 3.8. It is an extension of the Read Byte Protocol. Table 3.8 Block Read Protocol START SLAVE ADDRESS WR ACK REGISTER ADDRESS ACK START SLAVE ADDRESS RD ACK REGISTER DATA 1->0 YYYY_YYYb 0 0 XXh 0 1 ->0 YYYY_YYYb 1 0 XXh ACK REGISTER DATA ACK REGISTER DATA ACK REGISTER DATA ACK ... REGISTER DATA NACK STOP 0 XXh 0 XXh 0 XXh 0 ... XXh 1 0 -> 1 3.2.7 Alert Response Address The ALERT# output can be used as a processor interrupt or as an SMBus Alert when configured to operate as an interrupt. When it detects that the ALERT# pin is asserted, the host will send the Alert Response Address (ARA) to the general address of 0001_100xb. All devices with active interrupts will respond with their client address as shown in Table 3.9. Revision 1.3 (05-18-11) 16 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 3.9 Alert Response Address Protocol START ALERT RESPONSE ADDRESS RD ACK DEVICE ADDRESS NACK STOP 1 -> 0 0001_100b 1 0 YYYY_YYYb 1 0 -> 1 The EMC2305 will respond to the ARA in the following way if the ALERT# pin is asserted. 1. Send Slave Address and verify that full slave address was sent (i.e. the SMBus communication from the device was not prematurely stopped due to a bus contention event). 2. Set the MASK bit to clear the ALERT# pin. SMSC EMC2305 17 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Chapter 4 Product Description The EMC2305 is an SMBus compliant fan controller with five programmable frequency PWM fan drivers. The fan drivers can be operated using two modes: the RPM-based Fan Speed Control Algorithm or the direct fan drive setting. Figure 4.1 shows a system diagram of the EMC2305. 3.3V VDD TACH5 SMCLK MCU SMDATA PWM5 ALERT# tachometer Drive Circuit ADDR_SEL EMC2305 TACH4 tachometer Drive Circuit TACH1 PWM4 Drive Circuit Drive Circuit PWM1 TACH3 tachometer tachometer PWM3 TACH2 PWM2 CLK tachometer Drive Circuit 32.768KHz Clock Input or Output GND Figure 4.1 System Diagram of EMC2305 4.1 Fan Control Modes of Operation The EMC2305 has two modes of operation for each fan driver. Each mode of operation uses the Ramp Rate control and Spin Up Routine. 1. Direct Setting Mode - in this mode of operation, the user directly controls the fan drive setting. Updating the Fan Driver Setting Register (see Section 5.7) will instantly update the PWM fan drive. Ramp Rate control is optional and enabled via the EN_RRC bits. Revision 1.3 (05-18-11) 18 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Whenever the Direct Setting Mode is enabled, the current drive will be changed to what was last written into the Fan Driver Setting Register. 2. Fan Speed Control Mode (FSC) - in this mode of operation, the user determines a target tachometer count and the PWM drive setting is automatically updated to achieve this target speed. The algorithm uses the Spin Up Routine and has user definable ramp rate controls. This mode is enabled setting the EN_ALGO bit in the Fan Configuration Register. Table 4.1 Fan Controls Active for Operating Mode DIRECT SETTING MODE FSC MODE Fan Driver Setting (read / write) Fan Driver Setting (read only) EDGES[1:0] EDGES[1:0] (Fan Configuration) - RANGE[1:0] (Fan Configuration) UPDATE[2:0] (Fan Configuration) UPDATE[2:0] (Fan Configuration) LEVEL (Spin Up Configuration) LEVEL (Spin Up Configuration) SPINUP_TIME[1:0] (Spin Up Configuration) SPINUP_TIME[1:0] (Spin Up Configuration) Fan Step Fan Step - Fan Minimum Drive Valid TACH Count Valid TACH Count - TACH Target (read / write) TACH Reading TACH Reading - DRIVE_FAIL_CNT[1:0] and Drive Band Fail Registers 4.2 PWM Fan Driver The EMC2305 supports 5 PWM output drivers. Each output driver can be configured to operate as an open-drain (default) or push-pull driver and each driver can be configured with normal or inverse polarity. Additionally, the PWM frequencies are independently programmable with ranges from 9.5Hz to 26kHz in four programmable frequency bands. 4.3 RPM-based Fan Speed Control Algorithm (FSC) The EMC2305 includes 5 RPM-based Fan Speed Control Algorithms. Each algorithm operates independently and controls a separate fan driver. Each algorithm is controlled manually (by setting the target fan speed). This fan control algorithm uses Proportional, Integral, and Derivative terms to automatically approach and maintain the system’s desired fan speed to an accuracy directly proportional to the accuracy of the clock source. The desired tachometer count is set by the user inputting the desired number of 32.768kHz cycles that occur per fan revolution. This is done by manually setting the TACH Target Register. The user may SMSC EMC2305 19 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet change the target count at any time. The user may also set the target count to FFh in order to disable the fan driver for lower current operation. For example, if a desired RPM rate for a 2-pole fan is 3000 RPMs, then the user would input the hexidecimal equivalent of 1296 (51h in the TACH Target Register). This number represents the number of 32.768KHz cycles that would occur during the time it takes the fan to complete a single revolution when it is spinning at 3000RPMs. The EMC2305’s RPM-based Fan Speed Control Algorithm has programmable configuration settings for parameters such as ramp-rate control and spin up conditions. The fan driver automatically detects and attempts to alleviate a stalled/stuck fan condition while also asserting the ALERT# pin. The EMC2305 works with fans that operate up to 16,000 RPMs and provide a valid tachometer signal. The fan controller will function either with an externally supplied 32.768kHz clock source or with it’s own internal 32kHz oscillator depending on the required accuracy. The EMC2305 offers a clock output that enables additional devices to be slaved to the same clock source. 4.3.1 Programming the RPM-based Fan Speed Control Algorithm The RPM-based Fan Speed Control Algorithm is disabled upon device power up. The following registers control the algorithm. The EMC2305 fan control registers are pre-loaded with defaults that will work for a wide variety of fans so only the TACH Target Register is required to set a fan speed. The other fan control registers can be used to fine-tune the algorithm behavior based on application requirements. Note that steps 1 - 6 are optional and need only be performed if the default settings do not provide the desired fan response. 1. Set the Spin Up Configuration Register to the Spin Up Level and Spin Time desired. 2. Set the Fan Step Register to the desired step size. 3. Set the Fan Minimum Drive Register to the minimum drive value that will maintain fan operation. 4. Set the Update Time and Edges options in the Fan Configuration Register. 5. Set the Valid TACH Count Register to the highest tach count that indicates the fan is spinning. Refer to AN17.4 RPM to TACH Counts Conversion for examples and tables for supported RPM ranges (500, 1k, 2k, 4k). 6. Set the TACH Target Register to the desired tachometer count. 7. Enable the RPM-based Fan Speed Control Algorithm by setting the EN_ALGO bit. 4.4 Tachometer Measurement The tachometer measurement circuitry is used in conjunction with the RPM-based Fan Speed Control Algorithm to update the fan driver output. Additionally, it can be used in Direct Setting mode as a diagnostic for host based fan control. This method monitors the TACHx signal in real time. It constantly updates the tachometer measurement by reporting the number of clocks between a user programmed number of edges on the TACHx signal (see Table 5.12). The tachometer measurement provides fast response times for the RPM-based Fan Speed Control Algorithm and the data is presented as a count value that represents the fan RPM period. APPLICATION NOTE: The tachometer measurement method works independently of the drive settings. If the device is put into Direct Setting and the fan drive is set at a level that is lower than the fan can operate (including zero drive), then the tachometer measurement may signal a Stalled Fan condition and assert an interrupt. Revision 1.3 (05-18-11) 20 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 4.4.1 Stalled Fan A Stalled fan is detected if the tach counter exceeds the user-programmable Valid TACH Count setting. If a stall is detected, the device will flag the fan as stalled and trigger an interrupt. If the RPM-based Fan Speed Control Algorithm is enabled, the algorithm will automatically attempt to restart the fan until it detects a valid tachometer level or is disabled. The FAN_STALL Status bit indicates that a stalled fan was detected. This bit is checked conditionally depending on the mode of operation. 4.4.2 Whenever the Direct Setting Mode or the Spin Up Routine is enabled, the FAN_STALL interrupt will be masked for the duration of the programmed Spin Up Time (see Table 5.22) to allow the fan to reach a valid speed without generating unnecessary interrupts. In Direct Setting Mode, whenever the TACH Reading Register value exceeds the Valid TACH Count Register setting, the FAN_STALL status bit will be set. When using the RPM-based Fan Speed Control Algorithm, the stalled fan condition is checked whenever the Update Time is met and the fan drive setting is updated. It is not a continuous check. Aging Fan or Invalid Drive Detection This is useful to detect aging fan conditions (where the fan’s natural maximum speed degrades over time) or a speed setting that is faster than the fan is capable of. The EMC2305 contains circuitry that detects that the programmed fan speed can be reached by the fan. If the target fan speed cannot be reached within a user defined band of tach counts at maximum drive, the DRIVE_FAIL status bits are set and the ALERT# pin is asserted. 4.5 CLK Pin The CLK pin has multiple functionality as determined by the pull-up decode of the ADDR_SEL pin and the settings of the Configuration register. The functionality associated with the CLK pin upon device power up is independent of the CLK pin functionality after the device has been configured. 4.5.1 Pull Up Decode If additional functionality is enabled via the ADDR_SEL pin (see Section 3.1.2), then the CLK pin should be configured with a pull-up resistor to VDD and should not be used. The value of the pull-up resistor on the CLK pin is used to determine the default drive state of all fan drivers as shown in Table 4.2. Table 4.2 CLK Pin Pull-Up Decode SMSC EMC2305 PULL-UP RESISTOR FAN DEFAULT DRIVE SETTING 4.7k Ohm ±5% 0% - OFF 6.8k Ohm ±5% 30% 10k Ohm ±5% 50% 15k Ohm ±5% 75% 22k Ohm ±5% 100% 33k Ohm ±5% 0% - OFF 21 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 4.5.2 External Clock The EMC2305 allows the user to choose between supplying an external 32.768kHz clock or use of the internal 32kHz oscillator to measure the tachometer signal. This clock source is used by the RPMbased Fan Speed Control Algorithm to calculate the current fan speed. This fan controller accuracy is directly proportional to the accuracy of the clock source. When this function is used, the external clock is driven into the device via the CLK pin. 4.5.3 Internal Clock Alternately, the EMC2305 may be configured to use its internal clock as a clock output to drive other fan driver devices. When configured to operate in this mode, the device uses its internal clock for tachometer reading and drives the CLK pin using a push-pull driver. 4.6 Spin Up Routine The EMC2305 also contains programmable circuitry to control the spin up behavior of the fan driver to ensure proper fan operation. The Spin Up Routine is initiated in Direct Setting mode when the setting value changes from 00h to anything else. When the Fan Speed Control Algorithm is enabled, the Spin Up Routine is initiated under the following conditions: 1. The TACH Target Register value changes from a value of FFh to a value that is less than the Valid TACH Count (see Section 5.15). 2. The RPM-based Fan Speed Control Algorithm’s measured TACH Reading Register value is greater than the Valid TACH Count setting. When the Spin Up Routine is operating, the fan driver is set to full scale (optional) for one quarter of the total user defined spin up time. For the remaining spin up time, the fan driver output is set at a user defined level (30% through 65% drive). After the Spin Up Routine has finished, the EMC2305 measures the TACHx signal. If the measured TACH Reading Register value is higher than the Valid TACH Count Register setting, the FAN_SPIN status bit is set and the Spin Up Routine will automatically attempt to restart the fan. Figure 4.2 shows an example of the Spin Up Routine in response to a programmed fan speed change based on the first condition above. Revision 1.3 (05-18-11) 22 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 100% (optional) 30% through 65% Fan Step New Target Count Algorithm controlled drive Prev Target Count = FFh ¼ of Spin Up Time Update Time Spin Up Time Check TACH Target Count Changed Target Count Reached Figure 4.2 Spin Up Routine 4.6.1 Power Up Options The EMC2305 allows for one of four fan speed options upon device power up depending on the status of the pull-up resistor on the ADDR_SEL pin and the CLK pin. If the ADDR_SEL pin decode enables the CLK pin (see Table 3.1), then the value of the pull-up resistor on the CLK pin is used to determine the default fan drive setting (see Section 4.5.1). If the Fan drive setting is set at a non-zero value (as determined by the CLK pin), then the drive setting will be set to the desired setting. The Spin Up Routine will not be activated. This function does not disable the Watchdog timer which will continue to function normally. See Section 4.8. 4.7 Ramp Rate Control The Fan Driver can be configured with automatic ramp rate control. Ramp rate control is accomplished by adjusting the drive output settings based on the Maximum Fan Step Register settings and the Update Time settings. If the RPM-based Fan Speed Control Algorithm is used, then this ramp rate control is automatically used. The user programs a maximum step size for the fan drive setting and an update time. The update time varies from 100ms to 1.6s while the fan drive maximum step can vary from 1 count to 31 counts. When a new fan drive setting is entered, the delta from the next fan drive setting and the previous fan drive setting is determined. If this delta is greater than the Max Step settings, then the fan drive setting is incrementally adjusted every 100ms to 1.6s as determined by the Update Time until the target fan drive setting is reached. See Figure 4.3. SMSC EMC2305 23 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Next Desired Setting Max Step Max Step Previous Setting Update Time Update Time Setting Changed Figure 4.3 Ramp Rate Control 4.8 Watchdog Timer The EMC2305 contains an internal Watchdog Timer for all fan drivers. The Watchdog timer monitors the SMBus traffic for signs of activity and works in two different modes based upon device operation. These modes are Power Up Operation and Continuous Operation as described below. For either mode of operation, if four (4) seconds elapse without activity detected by the host, then the watchdog will be triggered and the following will occur: 1. The WATCH status bit will be set. 2. The fan driver will be set to full scale drive. It will remain at full scale drive until it is disabled. 3. The ALERT# pin is asserted. APPLICATION NOTE: When the Watchdog timer is activated, the Fan Speed Control Algorithm is automatically disabled. Disabling the Watchdog will not automatically set the fan drive nor re-activate the Fan Speed Control Algorithm. This must be done manually. 4.8.1 Power Up Operation The Watchdog Timer only starts immediately after power-up. Once it has been triggered or deactivated, it will not restart although it can be configured to operate in Continuous operation. While the Watchdog timer is active, the device will not check for a Stalled Fan condition. Revision 1.3 (05-18-11) 24 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet In the Power Up Operation, the Watchdog Timer is disabled by any of the following actions: 1. Writing the Fan Setting Register will disable the Watchdog Timer. 2. Enabling the RPM-based Fan Speed Control Algorithm by setting the EN_ALGO bit will disable the Watchdog Timer. The fan driver will be set based on the RPM-based Fan Speed Control Algorithm. Writing any other configuration registers will not disable the Watchdog Timer upon power up. 4.8.2 Continuous Operation When configured to operate in Continuous Operation, the Watchdog timer will start immediately. The timer will be reset by any access (read or write) to the SMBus register set. The four second Watchdog timer will restart upon completion of SMBus activity. SMSC EMC2305 25 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Chapter 5 Register Set 5.1 Register Map The following registers are accessible through the SMBus Interface. All register bits marked as ‘-’ will always read ‘0’. A write to these bits will have no effect. Table 5.1 EMC2305 Register Set ADDR REGISTER NAME R/W FUNCTION DEFAULT VALUE LOCK PAGE Configuration and control 20h R/W Configuration Configures the clocking and watchdog functionality 40h SWL Page 31 24h R-C Fan Status Stores the status bits for the RPMbased Fan Speed Control Algorithm 00h No Page 32 25h R-C Fan Stall Status Stores status bits associated with a stalled fan 00h No Page 32 26h R-C Fan Spin Status Stores status bits associated with a spin-up failure 00h No Page 32 27h R-C Drive Fail Status Stores status bits associated with drive failure 00h No Page 32 29h R/W Fan Interrupt Enable Register Controls the masking of interrupts on all fan related channels 00h No Page 33 2Ah R/W PWM Polarity Config Configures Polarity of all PWM drivers 00h No Page 34 2Bh R/W PWM Output Config Configures Output type of PWM drivers 00h No Page 34 2Ch R/W PWM Base Frequency 1 Selects the base frequency for PWM outputs 5 - 4 00h No Page 35 2Dh R/W PWM Base Frequency 2 Selects the base frequency for PWM outputs 3 - 1 00h No Page 35 00h No Page 36 Fan 1 Control Registers 30h R/W Fan 1 Setting Always displays the most recent fan driver input setting for Fan 1. If the RPM-based Fan Speed Control Algorithm is disabled, allows direct user control of the fan driver. 31h R/W PWM 1 Divide Stores the divide ratio to set the frequency for Fan 1 01h No Page 36 32h R/W Fan 1 Configuration 1 Sets configuration values for the RPMbased Fan Speed Control Algorithm for the Fan 1 driver 2Bh No Page 37 33h R/W Fan 1 Configuration 2 Sets additional configuration values for the Fan 1 driver 28h SWL Page 38 Revision 1.3 (05-18-11) 26 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 5.1 EMC2305 Register Set (continued) ADDR R/W REGISTER NAME DEFAULT VALUE LOCK PAGE 35h R/W Gain 1 Holds the gain terms used by the RPMbased Fan Speed Control Algorithm for the Fan 1 driver 2Ah SWL Page 40 36h R/W Fan 1 Spin Up Configuration Sets the configuration values for Spin Up Routine of the Fan 1 driver 19h SWL Page 41 37h R/W Fan 1 Max Step Sets the maximum change per update for the Fan 1 driver 10h SWL Page 43 38h R/W Fan 1 Minimum Drive Sets the minimum drive value for the Fan 1 driver 66h (40%) SWL Page 44 39h R/W Fan 1 Valid TACH Count Holds the tachometer reading that indicates Fan 1 is spinning properly F5h SWL Page 44 3Ah R/W Fan 1 Drive Fail Band Low Byte 00h SWL 3Bh R/W Fan 1 Drive Fail Band High Byte Stores the number of Tach counts used to determine how the actual fan speed must match the target fan speed at full scale drive 00h SWL 3Ch R/W TACH 1 Target Low Byte Holds the target tachometer reading low byte for Fan 1 F8h No Page 46 3Dh R/W TACH 1 Target High Byte Holds the target tachometer reading high byte for Fan 1 FFh No Page 46 3Eh R TACH 1 Reading High Byte Holds the tachometer reading high byte for Fan 1 FFh No Page 47 3Fh R TACH 1 Reading Low Byte Holds the tachometer reading low byte for Fan 1 F8h No Page 47 00h No Page 36 FUNCTION Page 45 Fan 2 Control Registers 40h R/W Fan 2 Setting Always displays the most recent fan driver input setting for Fan 2. If the RPM-based Fan Speed Control Algorithm is disabled, allows direct user control of the fan driver. 41h R/W PWM 2 Divide Stores the divide ratio to set the frequency for Fan 2 01h No Page 36 42h R/W Fan 2 Configuration1 Sets configuration values for the RPMbased Fan Speed Control Algorithm for Fan 2 2Bh No Page 37 43h R/W Fan 2 Configuration 2 Sets additional configuration values for the Fan 2 driver 28h SWL Page 38 45h R/W Gain 2 Holds the gain terms used by the RPMbased Fan Speed Control Algorithm for Fan 2 2Ah SWL Page 40 46h R/W Fan 2 Spin Up Configuration Sets the configuration values for Spin Up Routine of the Fan 2 driver 19h SWL Page 41 SMSC EMC2305 27 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 5.1 EMC2305 Register Set (continued) ADDR R/W REGISTER NAME DEFAULT VALUE LOCK PAGE 47h R/W Fan 2 Max Step Sets the maximum change per update for Fan 2 10h SWL Page 43 48h R/W Fan 2 Minimum Drive Sets the minimum drive value for the Fan 2 driver 66h (40%) SWL Page 44 49h R/W Fan 2 Valid TACH Count Holds the tachometer reading that indicates Fan 2 is spinning properly F5h SWL Page 44 4Ah R/W Fan 2 Drive Fail Band Low Byte 00h SWL 4Bh R/W Fan 2 Drive Fail Band High Byte Stores the number of Tach counts used to determine how the actual fan speed must match the target fan speed at full scale drive 4Ch R/W TACH 2 Target Low Byte 4Dh R/W 4Eh 4Fh FUNCTION Page 45 00h SWL Holds the target tachometer setting low byte for Fan 2 F8h No Page 46 TACH 2 Target High Byte Holds the target tachometer setting high byte for Fan 2 FFh No Page 46 R TACH 2 Reading High Byte Holds the tachometer reading high byte for Fan 2 FFh No Page 47 R TACH 2 Reading Low Byte Holds the tachometer reading low byte for Fan 2 F8h No Page 47 00h No Page 36 Fan 3 Control Registers 50h R/W Fan 3 Setting Always displays the most recent fan driver input setting for Fan 3. If the RPM-based Fan Speed Control Algorithm is disabled, allows direct user control of the fan driver. 51h R/W PWM 3 Divide Stores the divide ratio to set the frequency for Fan 3 01h No Page 36 52h R/W Fan 3 Configuration 1 Sets configuration values for the RPMbased Fan Speed Control Algorithm for the Fan 3 driver 2Bh No Page 37 53h R/W Fan 3 Configuration 2 Sets additional configuration values for the Fan 3 driver 28h SWL Page 38 55h R/W Gain 3 Holds the gain terms used by the RPMbased Fan Speed Control Algorithm for the Fan 3 driver 2Ah SWL Page 40 56h R/W Fan 3 Spin Up Configuration Sets the configuration values for Spin Up Routine of the Fan 3 driver 19h SWL Page 41 57h R/W Fan 3 Max Step Sets the maximum change per update for the Fan 3 driver 10h SWL Page 43 58h R/W Fan 3 Minimum Drive Sets the minimum drive value for the Fan 3 driver 66h (40%) SWL Page 44 59h R/W Fan 3 Valid TACH Count Holds the tachometer reading that indicates Fan 3 is spinning properly F5h SWL Page 44 Revision 1.3 (05-18-11) 28 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 5.1 EMC2305 Register Set (continued) REGISTER NAME DEFAULT VALUE LOCK 00h SWL 00h SWL Holds the target tachometer reading low byte for Fan 3 F8h No Page 46 TACH 3 Target High Byte Holds the target tachometer reading high byte for Fan 3 FFh No Page 46 R TACH 3 Reading High Byte Holds the tachometer reading high byte for Fan 3 FFh No Page 47 R TACH 3 Reading Low Byte Holds the tachometer reading low byte for Fan 3 F8h No Page 47 00h No Page 36 ADDR R/W 5Ah R/W Fan 3 Drive Fail Band Low Byte 5Bh R/W Fan 3 Drive Fail Band High Byte 5Ch R/W TACH 3 Target Low Byte 5Dh R/W 5Eh 5Fh FUNCTION Stores the number of Tach counts used to determine how the actual fan speed must match the target fan speed at full scale drive PAGE Page 45 Fan 4 Control Registers 60h R/W Fan 4 Setting Always displays the most recent fan driver input setting for Fan 4. If the RPM- based Fan Speed Control Algorithm is disabled, allows direct user control of the fan driver. 61h R/W PWM 4 Divide Stores the divide ratio to set the frequency for Fan 4 01h No Page 36 62h R/W Fan 4 Configuration1 Sets configuration values for the RPMbased Fan Speed Control Algorithm for Fan 4 2Bh No Page 37 63h R/W Fan 4 Configuration 2 Sets additional configuration values for the Fan 4 driver 28h SWL Page 38 65h R/W Gain 4 Holds the gain terms used by the RPMbased Fan Speed Control Algorithm for Fan 4 2Ah SWL Page 40 66h R/W Fan 4 Spin Up Configuration Sets the configuration values for Spin Up Routine of the Fan 4 driver 19h SWL Page 41 67h R/W Fan 4 Max Step Sets the maximum change per update for Fan 4 10h SWL Page 43 68h R/W Fan 4 Minimum Drive Sets the minimum drive value for the Fan 4 driver 66h (40%) SWL Page 44 69h R/W Fan 4 Valid TACH Count Holds the tachometer reading that indicates Fan 4 is spinning properly F5h SWL Page 44 6Ah R/W Fan 4 Drive Fail Band Low Byte 00h SWL 6Bh R/W Fan 4 Drive Fail Band High Byte Stores the number of Tach counts used to determine how the actual fan speed must match the target fan speed at full scale drive 00h SWL 6Ch R/W TACH 4 Target Low Byte Holds the target tachometer setting low byte for Fan 4 F8h No SMSC EMC2305 29 DATASHEET Page 45 Page 46 Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 5.1 EMC2305 Register Set (continued) REGISTER NAME FUNCTION R/W TACH 4 Target High Byte 6Eh R 6Fh R ADDR R/W 6Dh DEFAULT VALUE LOCK PAGE Holds the target tachometer setting high byte for Fan 4 FFh No Page 46 TACH 4 Reading High Byte Holds the tachometer reading high byte for Fan 4 FFh No Page 47 TACH 4 Reading Low Byte Holds the tachometer reading low byte for Fan 4 F8h No Page 47 00h No Page 36 Fan 5 Control Registers 70h R/W Fan 5 Setting Always displays the most recent fan driver input setting for Fan 5. If the RPM- based Fan Speed Control Algorithm is disabled, allows direct user control of the fan driver. 71h R/W PWM 5 Divide Stores the divide ratio to set the frequency for Fan 5 01h No Page 36 72h R/W Fan 5 Configuration1 Sets configuration values for the RPMbased Fan Speed Control Algorithm for Fan 5 2Bh No Page 37 73h R/W Fan 5 Configuration 2 Sets additional configuration values for the Fan 5 driver 28h SWL Page 38 75h R/W Gain 5 Holds the gain terms used by the RPMbased Fan Speed Control Algorithm for Fan 5 2Ah SWL Page 40 76h R/W Fan 5 Spin Up Configuration Sets the configuration values for Spin Up Routine of the Fan 5 driver 19h SWL Page 41 77h R/W Fan 5 Max Step Sets the maximum change per update for Fan 5 10h SWL Page 43 78h R/W Fan 5 Minimum Drive Sets the minimum drive value for the Fan 5 driver 66h (40%) SWL Page 44 79h R/W Fan 5 Valid TACH Count Holds the tachometer reading that indicates Fan 5 is spinning properly F5h SWL Page 44 7Ah R/W Fan 5 Drive Fail Band Low Byte 00h SWL 7Bh R/W Fan 5 Drive Fail Band High Byte Stores the number of Tach counts used to determine how the actual fan speed must match the target fan speed at full scale drive 00h SWL 7Ch R/W TACH 5 Target Low Byte Holds the target tachometer setting low byte for Fan 5 F8h No Page 46 7Dh R/W TACH 5 Target High Byte Holds the target tachometer setting high byte for Fan 5 FFh No Page 46 7Eh R TACH 5 Reading High Byte Holds the tachometer reading high byte for Fan 5 FFh No Page 47 7Fh R TACH 5 Reading Low Byte Holds the tachometer reading low byte for Fan 5 F8h No Page 47 Revision 1.3 (05-18-11) 30 DATASHEET Page 45 SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 5.1 EMC2305 Register Set (continued) ADDR R/W REGISTER NAME FUNCTION DEFAULT VALUE LOCK PAGE 00h SWL Page 48 Lock Register EF R/W Software Lock Locks all SWL registers Revision Registers FCh R Product Features Indicates functions determined upon device power up by external pin states 00h No Page 48 FDh R Product ID Stores the unique Product ID 34h No Page 49 FEh R Manufacturer ID Stores the Manufacturer ID 5Dh No Page 50 FFh R Revision Revision 80h No Page 50 During Power-On-Reset (POR), the default values are stored in the registers. A POR is initiated when power is first applied to the part and the voltage on the VDD supply surpasses the POR level as specified in the electrical characteristics. Any reads to undefined registers will return 00h. Writes to undefined registers will not have an effect. 5.1.1 Lock Entries The Lock Column describes the locking mechanism, if any, used for individual registers. All SWL registers are Software Locked and therefore made read-only when the LOCK bit is set. 5.2 Configuration Register Table 5.2 Configuration Register ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 20h R/W Configuration MASK DIS_TO WD_EN - - - DR_EXT_ CLK USE_ EXT_ CLK 40h The Configuration Register controls the basic functionality of the EMC2305. The bits are described below. The Configuration Register is software locked. Bit 7 - MASK - Blocks the ALERT# pin from being asserted. ‘0’ (default) - The ALERT# pin is unmasked. If any bit in the status registers is set, the ALERT# pin will be asserted (unless individually masked via the Fan Interrupt Enable Register). ‘1’ - The ALERT# pin is masked and will not be asserted. Bit 6 - DIS_TO - Disables the SMBus timeout function for the SMBus client (if enabled). ‘0’ - The SMBus timeout function is enabled. ‘1’ (default) - The SMBus timeout function is disabled allowing the device to be fully I2C compliant. Bit 5 - WD_EN - Enables the Watchdog timer (see Section 4.8) to operate in Continuous Mode. SMSC EMC2305 ‘0’ (default) - The Watchdog timer does not operate continuously. It will function upon power up and at no other time (see Section 4.8.1). ‘1’ - The Watchdog timer operates continuously as described in Section 4.8.2. 31 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Bit 1 - DR_EXT_CLK - Enables the internal tachometer clock to be driven out on the CLK pin so that multiple devices can be synced to the same source. ‘0’ (default) - The CLK pin acts as a clock input. ‘1’ - The CLK pin acts as a clock output and is a push-pull driver. Bit 0 - USE_EXT_CLK - Enables the EMC2305 to use a clock present on the CLK pin as the tachometer clock. If the DR_EXT_CLK bit is set, then this bit is ignored and the device will use the internal oscillator. 5.3 ‘0’ (default) - The EMC2305 will use its internal oscillator for all Tachometer measurements. ‘1’ - The EMC2305 will use the oscillator presented on the CLK pin for all Tachometer measurements. Fan Status Registers Table 5.3 Fan Status Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 24h R-C Fan Status WATCH - - - - DRIVE_ FAIL FAN_ SPIN FAN_ STALL 00h 25h R-C Fan Stall Status - - - FAN5_ STALL FAN4_ STALL FAN3_ STALL FAN2_ STALL FAN1_ STALL 00h 26h R-C Fan Spin Status - - - FAN5_ SPIN FAN4_ SPIN FAN3_ SPIN FAN2_ SPIN FAN1_ SPIN 00h 27h R-C Fan Drive Fail Status - - - DRIVE_ FAIL5 DRIVE_ FAIL4 DRIVE_ FAIL3 DRIVE_ FAIL2 DRIVE_ FAIL1 00h The Fan Status registers contain the status bits associated with each fan driver. 5.3.1 Fan Status - 24h The Fan Status register indicates that one or more of the fan drivers has stalled or failed or that the Watchdog Timer has expired (see Section 4.8). Bit 7 - WATCH - Indicates that the Watchdog Timer has expired. When set, each fan is driven to 100% duty cycle and will remain at 100% duty cycle until they are programmed. This bit is cleared when it is read. Bit 2 - DRIVE_FAIL - Indicates that one or more fan drivers cannot meet the programmed fan speed at maximum PWM duty cycle. This bit is set when any bit in the Fan Drive Fail Status register is set and cleared when all bits in the Fan Drive Fail Status register are cleared. Bit 1 - FAN_SPIN - Indicates that one or more fan drivers cannot spin up. This bit is set when any bit in the Fan Spin Status register is set and cleared when all of the bits in the Fan Spin Status register are cleared. Bit 0 - FAN_STALL - Indicates that one or more fan drivers have stalled. This bit is set when any bit in the Fan Stall Status register is set and cleared when all of the bits in the Fan Stall Status register are cleared. Revision 1.3 (05-18-11) 32 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 5.3.2 Fan Stall Status - 25h The Fan Stall Status register indicates which fan driver has detected a stalled condition (see Section 4.4.1). All bits are cleared upon a read if the error condition has been removed. Bit 4 - FAN5_STALL - Indicates that Fan 5 has stalled. Bit 3 - FAN4_STALL - Indicates that Fan 4 has stalled. Bit 2 - FAN3_STALL - Indicates that Fan 3 has stalled. Bit 1 - FAN2_STALL - Indicates that Fan 2 has stalled. Bit 0 - FAN1_STALL - Indicates that Fan 1 has stalled. 5.3.3 Fan Spin Status - 26h The Fan Spin Status register indicates which fan driver has failed to spin-up (see Section 4.6). All bits are cleared upon a read if the error condition has been removed. Bit 4 - FAN5_SPIN - Indicates that Fan 5 has failed to spin up. Bit 3 - FAN4_SPIN - Indicates that Fan 4 has failed to spin up. Bit 2 - FAN3_SPIN - Indicates that Fan 3 has failed to spin up. Bit 1 - FAN2_SPIN - Indicates that Fan 2 has failed to spin up. Bit 0 - FAN1_SPIN - Indicates that Fan 1 has failed to spin up. 5.3.4 Fan Drive Fail Status - 27h The Fan Drive Fail Status register indicates which fan driver cannot drive to the programmed speed even at 100% duty cycle (see Section 4.4.2 and Section 5.12). All bits are cleared upon a read if the error condition has been removed. Bit 4 - DRIVE_FAIL5 - Indicates that Fan 5 cannot reach its programmed fan speed even at 100% duty cycle. This may be due to an aging fan or invalid programming. Bit 3 - DRIVE_FAIL4 - Indicates that Fan 4 cannot reach its programmed fan speed even at 100% duty cycle. This may be due to an aging fan or invalid programming. Bit 2 - DRIVE_FAIL3 - Indicates that Fan 3 cannot reach its programmed fan speed even at 100% duty cycle. This may be due to an aging fan or invalid programming. Bit 1 - DRIVE_FAIL2 - Indicates that Fan 2 cannot reach its programmed fan speed even at 100% duty cycle. This may be due to an aging fan or invalid programming. Bit 0 - DRIVE_FAIL1 - Indicates that Fan 1 cannot reach its programmed fan speed even at 100% duty cycle. This may be due to an aging fan or invalid programming. 5.4 Fan Interrupt Enable Register Table 5.4 Fan Interrupt Enable Register ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 29h R/W Fan Interrupt Enable - - - FAN5_ INT_EN FAN4_ INT_EN FAN3_ INT_EN FAN2_ INT_EN FAN1_ INT_EN 00h SMSC EMC2305 33 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet The Fan Interrupt Enable controls the masking for each Fan channel. When a channel is enabled, it will cause the ALERT# pin to be asserted when an error condition is detected. Bit 4 - FAN5_INT_EN - Allows Fan 5 to assert the ALERT# pin if an error condition is detected. Bit 3 - FAN4_INT_EN - Allows Fan 4 to assert the ALERT# pin if an error condition is detected. Bit 2 - FAN3_INT_EN - Allows Fan 3 to assert the ALERT# pin if an error condition is detected. Bit 1 - FAN2_INT_EN - Allows Fan 2 to assert the ALERT# pin if an error condition is detected. Bit 0 - FAN1_INT_EN - Allows Fan 1 to assert the ALERT# pin if an error condition is detected. 5.5 ‘0’ (default) - An error condition on Fan X will not cause the ALERT# pin to be asserted, however the status registers will be updated normally. ‘1’ - An error condition (Stall, Spin Up, Drive Fail) on Fan X will cause the ALERT# pin to be asserted. PWM Configuration Registers Table 5.5 PWM Configuration Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 2Ah R/W PWM Polarity Config - - - POLARITY 5 POLARITY 4 POLARITY 3 POLARITY 2 POLARITY 1 00h 2Bh R/W PWM Output Config - - - PWM5_OT PWM4_OT PWM3_OT PWM2_OT PWM1_OT 00h The PWM Config registers control the output type and polarity of all PWM outputs. 5.5.1 PWM Polarity Config - 2Ah Bit 4 - POLARITY5 - Determines the polarity of PWM 5. Bit 3 - POLARITY4 - Determines the polarity of PWM 4. Bit 2 - POLARITY3 - Determines the polarity of PWM 3. Bit 1 - POLARITY2 - Determines the polarity of PWM 2. Bit 0 - POLARITY1 - Determines the polarity of PWM 1. 5.5.2 ‘0’ (default) - the Polarity of the PWM driver is normal. A drive setting of 00h will cause the output to be set at 0% duty cycle and a drive setting of FFh will cause the output to be set at 100% duty cycle. ‘1’ - The Polarity of the PWM driver is inverted. A drive setting of 00h will cause the output to be set at 100% duty cycle and a drive setting of FFh will cause the output to be set at 0% duty cycle. PWM Output Config - 2Bh Bit 4 - PWM5_OT - Determines the output type of the PWM 5 driver. Bit 3 - PWM4_OT - Determines the output type of the of PWM 4 driver. Bit 2 - PWM3_OT - Determines the output type of the of PWM 3 driver. Bit 1 - PWM2_OT - Determines the output type of PWM 2 driver. Revision 1.3 (05-18-11) 34 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Bit 0 - PWM1_OT - Determines the output type of the PWM 1 driver. 5.6 ‘0’ (default) - The PWM 1 output is configured as an open drain output. ‘1’ - The PWM 1 output is configured as a push-pull output. PWM Base Frequency Registers Table 5.6 PWM Base Frequency Registers ADDR R/W REGISTER B7 B6 B5 B4 2Ch R/W PWM Base Frequency 1 - - - - 2Dh R/W PWM Base Frequency 2 - - PWM_ BASE 3_1 PWM_ BASE 3_0 B3 B2 B1 PWM_BASE5 [1:0] PWM_ BASE 2_0 PWM_ BASE 2_1 B0 PWM_BASE4 [1:0] PWM_ BASE 1_1 PWM_ BASE 1_0 DEFAULT 00h 00h The PWM Base Frequency registers determine the base frequency that is used with the PWM Divide register to determine the final PWM frequency. Each PWM frequency is set by the base frequency and its respective divide ratio (see Section 5.8). 5.6.1 PWM Base Frequency 1 - 2Bh Controls the base frequency of PWM drivers 4 and 5. Bits 3-2 - PWM_BASE5[1:0] - Determines the base frequency of the PWM5 driver. Bits 1-0 - PWM_BASE4[1:0] - Determines the base frequency of the PWM4 driver. 5.6.2 PWM Base Frequency 2 - 2Ch Controls the base frequency of PWM drivers 1-3 Bits 5-6 - PWM_BASE3[1:0] - Determines the base frequency of the PWM3 driver. Bits 3-2 - PWM_BASE2[1:0] - Determines the base frequency of the PWM2 driver. Bits 1-0 - PWM_BASE1[1:0] - Determines the base frequency of the PWM1 driver. Table 5.7 PWM_BASEx[1:0] Bit Decode PWM_BASEX[1:0] 1 0 BASE FREQUENCY 0 0 26.00kHz (default) 0 1 19.531kHz 1 0 4,882Hz 1 1 2,441Hz SMSC EMC2305 35 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 5.7 Fan Setting Registers Table 5.8 Fan Driver Setting Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 30h R/W Fan 1 Setting 128 64 32 16 8 4 2 1 00h 40h R/W Fan 2 Setting 128 64 32 16 8 4 2 1 00h 50h R/W Fan 3 Setting 128 64 32 16 8 4 2 1 00h 60h R/W Fan 4 Setting 128 64 32 16 8 4 2 1 00h 70h R/W Fan 5 Setting 128 64 32 16 8 4 2 1 00h The Fan Setting register always displays the current setting of the respective fan driver. Reading from any of the registers will report the current fan speed setting of the appropriate fan driver regardless of the operating mode. Therefore it is possible that reading from this register will not report data that was previously written into this register. While the RPM-based Fan Speed Control Algorithm is active, the register is read only. Writing to the register will have no effect and the data will not be stored. The contents of the register represent the weighting of each bit in determining the final output voltage. The output drive for a PWM output is given by Equation [1]. VALUE Drive = ⎛ ---------------------⎞ × 100% ⎝ 255 ⎠ 5.8 [1] PWM Divide Registers Table 5.9 PWM Divide Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 31h R/W Fan 1 Divide 128 64 32 16 8 4 2 1 01h 41h R/W Fan 2 Divide 128 64 32 16 8 4 2 1 01h 51h R/W Fan 3 Divide 128 64 32 16 8 4 2 1 01h 61h R/W Fan 4 Divide 128 64 32 16 8 4 2 1 01h 71h R/W Fan 5 Divide 128 64 32 16 8 4 2 1 01h The PWM Divide registers determine the final frequency of the respective PWM Fan Driver. Each driver base frequency is divided by the value of the respective PWM Divide Register to determine the final frequency. The duty cycle settings are not affected by these settings, only the final frequency of the PWM driver. A value of 00h will be decoded as 01h. Revision 1.3 (05-18-11) 36 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 5.9 Fan Configuration 1 Registers Table 5.10 Fan Configuration 1 Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 32h R/W Fan 1 Configuration 1 EN_ ALGO1 RANGE1[1:0] EDGES1[1:0] UPDATE1[2:0] 2Bh 42h R/W Fan 2 Configuration 1 EN_ ALGO2 RANGE2[1:0] EDGES2[1:0] UPDATE2[2:0] 2Bh 52h R/W Fan 3 Configuration 1 EN_ ALGO3 RANGE3[1:0] EDGES3[1:0] UPDATE3[2:0] 2Bh 62h R/W Fan 4 Configuration 1 EN_ ALGO4 RANGE4[1:0] EDGES4[1:0] UPDATE4[2:0] 2Bh 72h R/W Fan 5 Configuration 1 EN_ ALGO5 RANGE5[1:0] EDGES5[1:0] UPDATE5[2:0] 2Bh The Fan Configuration 1 registers control the general operation of the RPM-based Fan Speed Control Algorithm used for the respective Fan Driver. Bit 7 - EN_ALGOx - enables the RPM-based Fan Speed Control Algorithm. ‘0’ - (default) the control circuitry is disabled and the fan driver output is determined by the Fan Driver Setting Register. ‘1’ - the control circuitry is enabled and the Fan Driver output will be automatically updated to maintain the programmed fan speed as indicated by the TACH Target Register. Bits 6- 5 - RANGEx[1:0] - Adjusts the range of reported and programmed tachometer reading values. The RANGE bits determine the weighting of all TACH values (including the Valid TACH Count, TACH Target, and TACH reading) as shown in Table 5.11. Table 5.11 Range Decode RANGEX[1:0] 1 0 REPORTED MINIMUM RPM TACH COUNT MULTIPLIER 0 0 500 1 0 1 1000 (default) 2 1 0 2000 4 1 1 4000 8 Bits 4-3 - EDGESx[1:0] - determines the minimum number of edges that must be detected on the TACHx signal to determine a single rotation. A typical fan measured 5 edges (for a 2-pole fan). For more accurate tachometer measurement, the minimum number of edges measured may be increased. Increasing the number of edges measured with respect to the number of poles of the fan will cause the TACH Reading registers to indicate a fan speed that is higher or lower than the actual speed. In order for the FSC Algorithm to operate correctly, the TACH Target must be updated by the user to accommodate this shift. The Effective Tach Multiplier shown in Table 5.12 is used as a direct multiplier term that is applied to the Actual RPM to achieve the Reported RPM. It should only be applied if the SMSC EMC2305 37 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet number of edges measured does not match the number of edges expected based on the number of poles of the fan (which is fixed for any given fan). Contact SMSC for recommended settings when using fans with more or less than 2 poles. Table 5.12 Minimum Edges for Fan Rotation EDGESX[1:0] 1 0 MINIMUM TACH EDGES NUMBER OF FAN POLES EFFECTIVE TACH MULTIPLIER (BASED ON 2 POLE FANS) 0 0 3 1 pole 0.5 0 1 5 2 poles (default) 1 0 7 3 poles 1.5 1 1 9 4 poles 2 1 Bit 2-0 - UPDATEx[2:0] - determines the base time between fan driver updates. The Update Time, along with the Fan Step Register, is used to control the ramp rate of the drive response to provide a cleaner transition of the actual fan operation as the desired fan speed changes. The Update Time is set as shown in Table 5.13. Table 5.13 Update Time UPDATEX[2:0] 5.10 2 1 0 UPDATE TIME 0 0 0 100ms 0 0 1 200ms 0 1 0 300ms 0 1 1 400ms (default) 1 0 0 500ms 1 0 1 800ms 1 1 0 1200ms 1 1 1 1600ms Fan Configuration 2 Registers Table 5.14 Fan Configuration 2 Registers ADDR R/W REGISTER B7 B6 B5 33h R/W Fan 1 Configuration 2 - EN_ RRC1 GLITCH_ EN1 DER_OPT1 [1:0] 43h R/W Fan 2 Configuration 2 - EN_ RRC2 GLITCH_ EN2 DER_OPT2 [1:0] Revision 1.3 (05-18-11) B4 38 DATASHEET B3 B2 B1 B0 DEFAULT ERR_RNG1[1:0] - 28h ERR_RNG2[1:0] - 28h SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 5.14 Fan Configuration 2 Registers (continued) ADDR R/W REGISTER B7 B6 B5 B4 B3 53h R/W Fan 3 Configuration 2 - EN_ RRC3 GLITCH_ EN3 DER_OPT3 [1:0] 63h R/W Fan 4 Configuration 2 - EN_ RRC4 GLITCH_ EN4 73h R/W Fan 5 Configuration 2 - EN_ RRC5 GLITCH_ EN5 B2 B1 B0 DEFAULT ERR_RNG3[1:0] - 28h DER_OPT4 [1:0] ERR_RNG4[1:0] - 28h DER_OPT5 [1:0] ERR_RN55[1:0] - 28h The Fan Configuration 2 registers control the tachometer measurement and advanced features of the RPM-based Fan Speed Control Algorithm. Bit 6 - EN_RRCx - Enables ramp rate control when the corresponding fan driver is operated in the Direct Setting Mode. ‘0’ (default) - Ramp rate control is disabled. When the fan driver is operating in Direct Setting mode, the fan setting will instantly transition to the next programmed setting. ‘1’ - Ramp rate control is enabled. When the fan driver is operating in Direct Setting mode, the fan drive setting will follow the ramp rate controls as determined by the Fan Step and Update Time settings. The maximum fan drive setting step is capped at the Fan Step setting and is updated based on the Update Time as given by Table 5.13. Bit 5 - GLITCH_ENx - Disables the low pass glitch filter that removes high frequency noise injected on the TACHx pin. ‘0’ - The glitch filter is disabled. ‘1’ (default) - The glitch filter is enabled. Bits 4 - 3 - DER_OPTx[1:0] - Control some of the advanced options that affect the derivative portion of the RPM-based Fan Speed Control Algorithm as shown in Table 5.15. Table 5.15 Derivative Options DER_OPTX[1:0] 1 0 OPERATION 0 0 No derivative options used 1 Basic derivative. The derivative of the error from the current drive setting and the target is added to the iterative Fan Drive Register setting (in addition to proportional and integral terms) (default) 1 0 Step derivative. The derivative of the error from the current drive setting and the target is added to the iterative Fan Drive Register setting and is not capped by the Fan Step Register. 1 1 Both the basic derivative and the step derivative are used effectively causing the derivative term to have double the effect of the derivative term. 0 Bit 2 - 1 - ERR_RNGx[1:0] - Control some of the advanced options that affect the error window. When the measured fan speed is within the programmed error window around the target speed, then the fan SMSC EMC2305 39 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet drive setting is not updated. The algorithm will continue to monitor the fan speed and calculate necessary drive setting changes based on the error; however, these changes are ignored. Table 5.16 Error Range Options ERR_RNGX[1:0] 5.11 1 0 OPERATION 0 0 0 RPM (default) 0 1 50 RPM 1 0 100 RPM 1 1 200 RPM Gain Registers Table 5.17 Gain Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 35h R/W Gain 1 Register - - GAIND1[1:0] GAINI1[1:0] GAINP1[1:0] 2Ah 45h R/W Gain 2 Register - - GAIND2[1:0] GAINI2[1:0] GAINP2[1:0] 2Ah 55h R/W Gain 3 Register - - GAIND3[1:0] GAINI3[1:0] GAINP3[1:0] 2Ah 65h R/W Gain 4 Register - - GAIND4[1:0] GAINI4[1:0] GAINP4[1:0] 2Ah 75h R/W Gain 5 Register - - GAIND5[1:0] GAINI5[1:0] GAINP5[1:0] 2Ah The Gain registers store the gain terms used by the proportional and integral portions of each of the RPM-based Fan Speed Control Algorithms. These gain terms are used as the KD, KI, and KP gain terms in a classic PID control solution. Bits 5 - 4 - GAINDX[1:0] - Controls the derivative gain term used by the FSC algorithm as shown in Table 5.18. Bits 3-2 - GAINIX[1:0] - Controls the integral gain term used by the FSC algorithm as shown in Table 5.18. Bits 1-0 - GAINP[1:0] - Controls the proportional gain term used by the FSC algorithm as shown in Table 5.18. Revision 1.3 (05-18-11) 40 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 5.18 Gain Decode GAIND OR GAINP OR GAINI [1:0] 5.12 1 0 RESPECTIVE GAIN FACTOR 0 0 1x 0 1 2x 1 0 4x (default) 1 1 8x Fan Spin Up Configuration Registers Table 5.19 Fan Spin Up Configuration Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 36h R/W Fan 1 Spin Up Configuration DRIVE_FAIL_ CNT1 [1:0] NOKICK1 SPIN_LVL1[2:0] SPINUP_TIME 1 [1:0] 19h 46h R/W Fan 2 Spin up Configuration DRIVE_FAIL_ CNT2 [1:0] NOKICK2 SPIN_LVL2[2:0] SPINUP_TIME 2 [1:0] 19h 56h R/W Fan 3 Spin up Configuration DRIVE_FAIL_ CNT3 [1:0] NOKICK3 SPIN_LVL3[2:0] SPINUP_TIME 3[1:0] 19h 66h R/W Fan 4 Spin up Configuration DRIVE_FAIL_ CNT4 [1:0] NOKICK4 SPIN_LVL4[2:0] SPINUP_TIME 4 [1:0] 19h 76h R/W Fan 5 Spin up Configuration DRIVE_FAIL_ CNT5 [1:0] NOKICK5 SPIN_LVL5[2:0] SPINUP_TIME 5 [1:0] 19h The Fan Spin Up Configuration registers control the settings of Spin Up Routine. The Fan Spin Up Configuration registers are software locked. Bit 7 - 6 - DRIVE_FAIL_CNTx[1:0] - Determines how many update cycles are used for the Drive Fail detection function as shown in Table 5.20. This circuitry determines whether the fan can be driven to the desired tach target. Table 5.20 DRIVE_FAIL_CNT[1:0] Bit Decode DRIVE_FAIL_CNTX[1:0] 1 0 NUMBER OF UPDATE PERIODS 0 0 Disabled - the Drive Fail detection circuitry is disabled (default) 0 1 16 - the Drive Fail detection circuitry will count for 16 update periods SMSC EMC2305 41 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 5.20 DRIVE_FAIL_CNT[1:0] Bit Decode (continued) DRIVE_FAIL_CNTX[1:0] 1 0 NUMBER OF UPDATE PERIODS 1 0 32 - the Drive Fail detection circuitry will count for 32 update periods 1 1 64 - the Drive Fail detection circuitry will count for 64 update periods Bit 5 - NOKICKx - Determines if the Spin Up Routine will drive the fan to 100% duty cycle for 1/4 of the programmed spin up time before driving it at the programmed level. ‘0’ (default) - The Spin Up Routine will drive the fan driver to 100% for 1/4 of the programmed spin up time before reverting to the programmed spin level. ‘1’ - The Spin Up Routine will not drive the fan driver to 100%. It will set the drive at the programmed spin level for the entire duration of the programmed spin up time. Bits 4 - 2 - SPIN_LVLx[2:0] - Determines the final drive level that is used by the Spin Up Routine as shown in Table 5.21. Table 5.21 Spin Level SPIN_LVLX[2:0] 2 1 0 SPIN UP DRIVE LEVEL 0 0 0 30% 0 0 1 35% 0 1 0 40% 0 1 1 45% 1 0 0 50% 1 0 1 55% 1 1 0 60% (default) 1 1 1 65% Bit 1 -0 - SPINUP_TIMEx[1:0] - determines the maximum Spin Time that the Spin Up Routine will run for (see Section 4.6). If a valid tachometer measurement is not detected before the Spin Time has elapsed, an interrupt will be generated. When the RPM-based Fan Speed Control Algorithm is active, the fan driver will attempt to re-start the fan immediately after the end of the last spin up attempt. The Spin Time is set as shown in Table 5.22. Revision 1.3 (05-18-11) 42 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 5.22 Spin Time SPINUP_TIMEX[1:0] 5.13 1 0 TOTAL SPIN UP TIME 0 0 250 ms 0 1 500 ms (default) 1 0 1 sec 1 1 2 sec Fan Max Step Registers Table 5.23 Fan Max Step Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 37h R/W Fan 1 Max Step - - 32 16 8 4 2 1 10h 47h R/W Fan 2 Max Step - - 32 16 8 4 2 1 10h 57h R/W Fan 3 Max Step - - 32 16 8 4 2 1 10h 67h R/W Fan 4 Max Step - - 32 16 8 4 2 1 10h 77h R/W Fan 5 Max Step - - 32 16 8 4 2 1 10h The Fan Max Step registers, along with the Update Time, control the ramp rate of the fan driver response calculated by the RPM-based Fan Speed Control Algorithm. The value of the register represents the maximum step size each fan driver will take between update times (see Section 5.9). When the FSC algorithm is enabled, Ramp Rate control is automatically used. When the FSC is not active, then Ramp Rate control can be enabled by asserting the EN_RRC bit (see Section 5.10). APPLICATION NOTE: The UPDATE bits and Fan Step Register settings operate independently of the RPM-based Fan Speed Control Algorithm and will always limit the fan drive setting. That is, if the programmed fan drive setting (either as determined by the RPM-based Fan Speed Control Algorithm or by manual settings) exceeds the current fan drive setting by greater than the Fan Step Register setting, the EMC2305 will limit the fan drive change to the value of the Fan Step Register. It will use the Update Time to determine how often to update the drive settings. APPLICATION NOTE: If the Fan Speed Control Algorithm is used, the default settings in the Fan Configuration 2 Register will cause the maximum fan step settings to be ignored. The Fan Max Step registers are software locked. SMSC EMC2305 43 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 5.14 Fan Minimum Drive Registers Table 5.24 Minimum Fan Drive Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 38h R/W Fan 1 Minimum Drive 128 64 32 16 8 4 2 1 66h (40%) 48h R/W Fan 2 Minimum Drive 128 64 32 16 8 4 2 1 66h (40%) 58h R/W Fan 3 Minimum Drive 128 64 32 16 8 4 2 1 66h (40%) 68h R/W Fan 4 Minimum Drive 128 64 32 16 8 4 2 1 66h (40%) 78h R/W Fan 5 Minimum Drive 128 64 32 16 8 4 2 1 66h (40%) The Fan Minimum Drive registers store the minimum drive setting for each RPM-based Fan Speed Control Algorithm. The RPM-based Fan Speed Control Algorithm will not drive the fan at a level lower than the minimum drive unless the target Fan Speed is set at FFh (see Section 5.17). During normal operation, if the fan stops for any reason (including low drive), the RPM-based Fan Speed Control Algorithm will attempt to restart the fan. Setting the Fan Minimum Drive Register to a setting that will maintain fan operation is a useful way to avoid potential fan oscillations as the control circuitry attempts to drive it at a level that cannot support fan operation. The Fan Minimum Drive Registers are software locked. 5.15 Valid TACH Count Registers Table 5.25 Valid TACH Count Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 39h R/W Valid TACH Count 1 4096 2048 1024 512 256 128 64 32 F5h 49h R/W Valid TACH Count 2 4096 2048 1024 512 256 128 64 32 F5h 59h R/W Valid TACH Count 3 4096 2048 1024 512 256 128 64 32 F5h 69h R/W Valid TACH Count 4 4096 2048 1024 512 256 128 64 32 F5h 79h R/W Valid TACH Count 5 4096 2048 1024 512 256 128 64 32 F5h Revision 1.3 (05-18-11) 44 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet The Valid TACH Count registers store the maximum TACH Reading Register value to indicate that each fan is spinning properly. The value is referenced at the end of the Spin Up Routine to determine if the fan has started operating and decide if the device needs to retry. See Equation [2] in Section 5.18 for translating the count to an RPM. If the TACH Reading Register value exceeds the Valid TACH Count Register (indicating that the Fan RPM is below the threshold set by this count), then a stalled fan is detected. In this condition, the algorithm will automatically begin its Spin Up Routine. If a TACH Target setting is set above the Valid TACH Count setting, then that setting will be ignored and the algorithm will use the current fan drive setting. The Valid TACH Count registers are software locked. 5.16 Fan Drive Fail Band Registers Table 5.26 Fan Drive Fail Band Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 3Ah R/W Fan 1 Drive Fail Band Low Byte 16 8 4 2 1 - - - 00h 3Bh R/W Fan 1 Drive Fail Band High Byte 4096 2048 1024 512 256 128 64 32 00h 4Ah R/W Fan 2 Drive Fail Band Low Byte 16 8 4 2 1 - - - 00h 4Bh R/W Fan 2 Drive Fall Band High Byte 4096 2048 1024 512 256 128 64 32 00h 5Ah R/W Fan 3 Drive Fail Band Low Byte 16 8 4 2 1 - - - 00h 5Bh R/W Fan 3 Drive Fail Band High Byte 4096 2048 1024 512 256 128 64 32 00h 6Ah R/W Fan 4 Drive Fail Band Low Byte 16 8 4 2 1 - - - 00h 6Bh R/W Fan 4 Drive Fall Band High Byte 4096 2048 1024 512 256 128 64 32 00h 7Ah R/W Fan 5 Drive Fail Band Low Byte 16 8 4 2 1 - - - 00h 7Bh R/W Fan 5 Drive Fall Band High Byte 4096 2048 1024 512 256 128 64 32 00h SMSC EMC2305 45 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet The Fan Drive Fail Band Registers store the number of tach counts used by the Fan Drive Fail detection circuitry. This circuitry is activated when the fan drive setting high byte is at FFh. When it is enabled, the actual measured fan speed is compared against the target fan speed. These registers are only used when the FSC is active. This circuitry is used to indicate that the target fan speed at full drive is higher than the fan is actually capable of reaching. If the measured fan speed does not exceed the target fan speed minus the Fan Drive Fail Band Register settings for a period of time longer than set by the DRIVE_FAIL_CNTx[1:0] bits, then the DRIVE_FAIL status bit will be set and an interrupt generated. 5.17 TACH Target Registers Table 5.27 TACH Target Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 3Ch R/W TACH Target 1 Low Byte 16 8 4 2 1 - - - F8h 3Dh R/W TACH Target 1 High Byte 4096 2048 1024 512 256 128 64 32 FFh 4Ch R TACH Target 2 Low Byte 16 8 4 2 1 - - - F8h 4Dh R/W TACH Target 2 High Byte 4096 2048 1024 512 256 128 64 32 FFh 5Ch R TACH Target 3 Low Byte 16 8 4 2 1 - - - F8h 5Dh R/W TACH Target 3 High Byte 4096 2048 1024 512 256 128 64 32 FFh 6Ch R TACH Target 4 Low Byte 16 8 4 2 1 - - - F8h 6Dh R/W TACH Target 4 High Byte 4096 2048 1024 512 256 128 64 32 FFh 7Ch R TACH Target 5 Low Byte 16 8 4 2 1 - - - F8h 7Dh R/W TACH Target 5 High Byte 4096 2048 1024 512 256 128 64 32 FFh The TACH Target Registers hold the target tachometer value that is maintained by the RPM-based Fan Speed Control Algorithm. The value in the TACH Target Registers will always reflect the current TACH Target value. If one of the algorithms is enabled, setting the TACH Target Register to FFh will disable the fan driver (set the fan drive setting to 0%). Setting the TACH Target to any other value (from a setting of FFh) will cause the algorithm to invoke the Spin Up Routine after which it will function normally. The Tach Target is not applied until the high byte is written. Once the high byte is written, the current value of both high and low bytes will be used as the next Tach target. Revision 1.3 (05-18-11) 46 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 5.18 TACH Reading Registers Table 5.28 TACH Reading Registers ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT 3Eh R Fan 1 TACH 4096 2048 1024 512 256 128 64 32 FFh 3Fh R Fan 1 TACH Low Byte 16 8 4 2 1 - - - F8h 4Eh R Fan 2 TACH 4096 2048 1024 512 256 128 64 32 FFh 4Fh R Fan 2 TACH Low Byte 16 8 4 2 1 - - - F8h 5Eh R Fan 3 TACH 4096 2048 1024 512 256 128 64 32 FFh 5Fh R Fan 3 TACH Low Byte 16 8 4 2 1 - - - F8h 6Eh R Fan 4 TACH 4096 2048 1024 512 256 128 64 32 FFh 6Fh R Fan 4 TACH Low Byte 16 8 4 2 1 - - - F8h 7Eh R Fan 5 TACH 4096 2048 1024 512 256 128 64 32 FFh 7Fh R Fan 5 TACH Low Byte 16 8 4 2 1 - - - F8h The TACH Reading Registers’ contents describe the current tachometer reading for each of the fans. By default, the data represents the fan speed as the number of 32kHz clock periods that occur for a single revolution of the fan. Equation [2] shows the detailed conversion from TACH measurement (COUNT) to RPM while Equation [3] shows the simplified translation of TACH Reading Register count to RPM assuming a 2-pole fan, measuring 5 edges, with a frequency of 32.768kHz. These equations are solved and tabulated for ease of use in AN17.4 RPM to TACH Counts Conversion. Whenever the high byte register is read, the corresponding low byte data will be loaded to internal shadow registers so that when the low byte is read, the data will always coincide with the previously read high byte. SMSC EMC2305 47 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet where: poles = number of poles of the fan (typically 2) 1 (n – 1) RPM = -------------------- × ---------------------------------- × f TACH × 60 1 ( poles ) COUNT × ----m fTACH = the tachometer measurement frequency (typically 32.768kHz) [2] n = number of edges measured (typically 5 for a 2 pole fan) m = the multiplier defined by the RANGE bits 3,932,160 × m RPM = -------------------------------------COUNT 5.19 [3] COUNT = TACH Reading Register value (in decimal) Software Lock Register Table 5.29 Software Lock Register ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT EFh R/W Software Lock - - - - - - - LOCK 00h The Software Lock Register controls the software locking of critical registers. This register is software locked. Bit 0 - LOCK - this bit acts on all registers that are designated SWL. When this bit is set, the locked registers become read only and cannot be updated. 5.20 ‘0’ (default) - all SWL registers can be updated normally. ‘1’ - all SWL registers cannot be updated and a hard-reset is required to unlock them. Product Features Register Table 5.30 Product Features Register ADDRESS R/W REGISTER B7 B6 FCh R Product Features - - B5 B4 ADR[2:0] B3 B2 B1 B0 FAN_SPD [2:0] DEFAULT 00h The Product Features register shows those functions that are enabled by external pin states. Bits 5-3 - ADR[2:0] - Indicates the selected SMBus address as determined by the ADDR_SEL pin. Revision 1.3 (05-18-11) 48 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Table 5.31 ADDR_SEL Pin Configuration ADR[2:0] SLAVE ADDRESS 2 1 0 0 0 0 0101_110(r/w) 0 0 1 0101_111(r/w) 0 1 0 0101_100(r/w) 0 1 1 0101_101(r/w) 1 0 0 1001_100(r/w) 1 0 1 1001_101(r/w) Bits 2-0 - FAN_SPD[2:0] - Indicates the selected fan speed if the CLK pin pull-up decode is enabled via the ADDR_SEL pin. Table 5.32 FAN_SPD Pin Configuration FAN_SPD [2:0] FAN SPEED 5.21 2 1 0 0 0 0 0% Drive 0 0 1 30% Drive 0 1 0 50% Drive 0 1 1 75% Drive 1 0 0 100% Drive Product ID Register Table 5.33 Product ID Register ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT FDh R Product ID 0 0 1 1 0 1 0 0 34h The Product ID Register contains a unique 8-bit word that identifies the product. SMSC EMC2305 49 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 5.22 Manufacturer ID Register Table 5.34 Manufacturer ID Register ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT FEh R Manufacturer ID 0 1 0 1 1 1 0 1 5Dh The Manufacturer ID Register contains an 8-bit word that identifies SMSC. 5.23 Revision Register Table 5.35 Revision Register ADDR R/W REGISTER B7 B6 B5 B4 B3 B2 B1 B0 DEFAULT FFh R Revision 1 0 0 0 0 0 0 0 80h The Revision Register contains an 8-bit word that identifies the die revision. Revision 1.3 (05-18-11) 50 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Chapter 6 Typical Operating Curves The following Typical Operating Curves are included. Supply Current vs. Temperature Supply Current vs. Supply Voltage Fan TACH Accuracy vs. Temperature Fan TACH Accuracy vs. Supply Voltage PWM output frequency vs. Supply Voltage PWM output frequency vs. Temperature FSC Operation Supply Current vs. Supply Voltage 750 700 700 Supply SupplyCurrent Current(uA) (uA) Supply Current Supply Current(uA) (uA) Supply Current vs. Ambient Temperature 750 650 600 550 650 600 550 500 -50 0 50 100 500 2.95 150 3.05 3.15 AmbientTemperature Temperature (°C) (C) Tach Measurement Accuracy (%)(% Tach Measurement Accuracy Tach Measurement MeasurementAccuracy Accuracy(%) (% Tach 3.45 3.55 3.65 1 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 0 50 100 0.8 0.6 0.4 0.2 0 -0.2 -0.4 -0.6 -0.8 -1 2.95 150 3.05 3.15 3.25 3.35 3.45 3.55 3.65 Supply Voltage (V) (C) AmbientTemperautre Temperature (°C) SMSC EMC2305 3.35 Tachometer Measurement Accuracy vs. Supply Voltage Tachometer Measurement Accuracy vs. Ambient Temperature 1 -1 -50 3.25 Supply Voltage (V) (V) Supply Voltage 51 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet PWM Frequency vs. Ambient Temperature V DD = 3.3V, Base Frequncy = 26Khz PWM Frequency vs. Supply Voltage TA = 25C, Base Frequncy = 26Khz 27000 27000 26800 26800 26600 26400 PWM Frequency (Hz) PWM Frequency (Hz) 26600 26200 26000 25800 25600 25400 25200 26400 26200 26000 25800 25600 25400 25200 25000 -50 0 50 100 25000 2.95 150 3.05 T emp er at ur e ( C ) Ambient Temperature (°C) 3.15 3.25 3.35 3.45 3.55 3.65 Supply Voltage (V) FSC Algorithm Spin Up Routine – NoKick Spin Time = 1.0s; Spin Level = 50%; UpdateTime = 200ms; RPM Target from 0 RPM -> 8000 RPM @ time t = 0 FSC Algorithm Spin Up Routine Spin Time = 1.0s; Spin Level = 55%; Updated Time = 200ms; RPM Target from 0 RPM -> 8000 RPM @ time t = 0 PWM Output PWM Output 10x Zoom on PWM Output 10x Zoom on PWM Output Duty Cycle Measured = 53.8% t=0 t=0 Duty Cycle Measured = 50% FSC Algorithm PWM Ramping Update Time = 200ms; Max Step = 16 PWM counts RPM Target from 0 RPM -> 8000 RPM @ time t = 0 PWM Output 10x Zoom on PWM Output Spin Up Routine Ends – begins normal operation Update Time ends, PWM duty cycle changed Revision 1.3 (05-18-11) Duty Cycle Measured Update Time ends, PWM duty cycle changed 52 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Chapter 7 Package Drawing 7.1 EMC2305 Package Information Figure 7.1 Package Drawing - 16-Pin QFN 4mm x 4mm SMSC EMC2305 53 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Figure 7.2 Package Dimensions - 16-Pin QFN 4mm x 4mm Figure 7.3 PCB Footprint - 16-Pin QFN 4mm x 4mm Revision 1.3 (05-18-11) 54 DATASHEET SMSC EMC2305 Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet 7.2 Package Markings TOP 0.41 LINE: 1 – SMSC Logo without circled (R) symbol LINE: 2 – Device Number LINE: 3 – Last 7 digits of Lot Number LINE: 4 – Revision and Country Code (RCC) 2 3 0 5 - 1 1 2 3 4 5 6 a RCC e3 3x 0.56 PB-FREE/GREEN SYMBOL (Matte Sn) PIN 1 LINES 1 to 3: CENTER HORIZONTAL ALIGNMENT LINE 4: LEFT HORIZONTAL ALIGNMENT BOTTOM BOTTOM MARKING NOT ALLOWED Figure 7.4 EMC2305 Package Markings SMSC EMC2305 55 DATASHEET Revision 1.3 (05-18-11) Multiple RPM-Based PWM Fan Controller for Five Fans Datasheet Chapter 8 Datasheet Revision History Table 8.1 Customer Revision History REVISION LEVEL & DATE SECTION/FIGURE/ENTRY CORRECTION Section 4.8, "Watchdog Timer" The ALERT# pin is asserted when the watchdog is triggered. Section 5.2, "Configuration Register" Corrected description for MASK bit. Changed “If any bit in either status register is set, the ALERT# pins will be asserted (unless individually masked via the Mask Register)” to “If any bit in the status registers is set, the ALERT# pin will be asserted (unless individually masked via the Fan Interrupt Enable Register)”. Rev. 1.2 (03-22-10) Table 2.3, "SMBus Electrical Specifications" Updated SMBus Data Hold Time spec to 0 us Rev. 1.1 (10-12-09) Table 2.2, "Electrical Specifications" Tachometer Setting Accuracy max was changed from +/-3% to +/-2%. Chapter 6, Typical Operating Curves Added typical operating curves Rev. 1.3 (05-18-11) Rev. 1.0 (05-15-09) Revision 1.3 (05-18-11) Initial release of datasheet 56 DATASHEET SMSC EMC2305 www.s-manuals.com
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