SMSC EMC2102 6

Fan Speed Control with the EMC2102 Device

1 Overview

SMSC has introduced a series of Environmental Monitoring and Control (EMC) devices with integrated fan control. This fan controller family devices feature the advanced closed-loop fan control technology developed by SMSC’s engineering team.

This user manual provides detailed information about fan control features supported by one of those EMC devices -- EMC2102, with detailed hand-on experiments for configuring the devices in real applications.

2 Audience

This user manual assumes that the reader is familiar with the functionality of the EMC2102 device and its evaluation board. The goal of the user manual is to help users to evaluate the new EMC device using Chip Manager (ChipMan) software provided by SMSC. This user manual also can be used as a reference material for other EMC devices which have fan control features.

3 References

The following documents should be referenced when using this user manual:

EMC2102 Device Datasheet

EVB-EMC2102 Evaluation Board User Manual

EVB-EMC2102 Evaluation Board Schematics

ChipMan Software User Manual

4 The Evaluation System

The evaluation system used for this user manual has two major parts, as shown in Figure 4.1, "EMC2102 Fan Control Evaluation System":

An EMC2102 evaluation board (EVB-EMC2102) with on-board 5V DC fan (Figure 4.2)

A PC with SMSC ChipMan software installed (requiring XML file for EMC2102 device)

This user manual contains several groups of user experiments which cover most of the fan control features of the EMC2102 fan controller device. All examples are based on the 2102 device evaluation board (EVB-EMC2102) and its software, but the methods and the results will apply to other EMC2102 applications.

Revision 0.2 (09-17-07)

USER MANUAL

SMSC EMC2102

6

Contents

USER MANUAL Page Page Page Page Page Figure 4.1 EMC2102 Fan Control Evaluation System Figure 4.2 EVB-EMC2102Board 5.1.1ChipMan Installation 5.1.2Setting Up the ChipMan Figure 5.1 ChipMan Message for First Operation Note: Figure 5.2 ChipMan Device Selection Window Figure 5.3 Selecting the Device and Master Controller Type Figure 5.4 ChipMan Operation Window Notes: Figure 5.5 Changing Fan Speed 5.1.3Plotting From ChipMan Figure 5.6 Plotting from the ChipMan Figure 5.7 Plot Windows Figure 5.8 Plot Examples 5.2.1Getting Started 5.2.2Basic RPM Based Fan Control Figure 5.9 Plots for Proper Control Settings 5.2.3Effects of Loading Figure 5.10 Effects of Loading 5.2.4Register Change Summary Table 5.1 Register Change Summary for Experiment REGISTER DEFAULT 5.3.1Fan Control Parameters Figure 5.11 Fan Control Parameters 5.3.2Getting Started 5.3.3Forced Kick Function Figure 5.12 Forced Kick Function 5.3.4Spin-UpLevel Figure 5.13 60% Spin Level Setting 5.3.5Spin-UpTime Figure 5.14 Reduced Spin-upTime 5.3.6Register Change Summary Table 5.2 Register Change Summary for Experiment 5.4.1General Setup 5.4.2Controlling the Ramp Rate Figure 5.15 Default Ramp Rate Figure 5.16 Default Step Size with Different UPDATE Settings Figure 5.17 Default UPDATE with Different Step Size Settings Figure 5.18 Exceptionally Slow Rate 5.4.3Register Change Summary Table 5.3 Register Change Summary for Experiment 5.5.1General Setup 5.5.2Fan Configuration Register (52h) Figure 5.19 Update Time Modifications 5.5.3FAN Minimum Drive Register (55h) and Valid TACH Count (56h) Figure 5.20 Minimum Drive Setting Figure 5.21 Valid Tach Count Setting 5.5.4Register Change Summary Table 5.4 Register Change Summary for Experiment 5.6.1General Setup 5.6.2Fan Spin and Stall Interrupts Figure 5.22 Fan Spin and Stall 5.6.3Register Change Summary 5.7.1.1Case 1 - Spin-upLvel RPM < Valid RPM < Target RPM Figure 5.24 Theoretical Plot of Case Figure 5.25 Spin-upCase 1 Fix 5.7.1.2Case 2 - Valid RPM << Target RPM < Spin-upLevel RPM 5.7.1.3Case 3 - Valid RPM =< Target RPM << Spin-upLevel RPM Figure 5.30 Spin-upCase Figure 5.31 Spin-upRoutine Restarted During Normal Operation 5.7.1.4Case 4 - 4.Valid RPM < Spin-upLevel RPM (rpm60 or rpm75) < Target RPM 5.7.1.5Case 5 - Correct RPM Relationships with a Slow Response DC Fan Figure 6.1 A Typical 2-poleDC Fan Figure 6.2 Output Signal of a 2-poleFan Figure 6.3 Fan TACH Measurement With EMC2102 [1] 6.2.1General Setup 6.2.2Set the Correct LIMIT2K Value 6.2.3Determine the Number of Poles and the Maximum Fan Speed 6.2.4Determine the Minimum Startup Speed 6.2.5Determine the Stall Speed 6.2.6Determine the Minimum Valid TACH Speed 6.2.8.1Spin-upLEVEL (Register 53h[2]) 6.2.8.2Minimum Fan Speed 6.2.8.3Valid TACH Count Speed (Function of Register 56h) 6.2.8.4Maximum Fan Speed