Texas Instruments bq27500 5.8 POWER CONTROL 5.8.1 RESET FUNCTIONS

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5.8 POWER CONTROL5.8.1 RESET FUNCTIONS

Store

checksum

ActiveRAM

changed?

GenerateNew

checksumvalue

YES

GenerateActive

RAMchecksum

value

DotheChecksum

ValuesMatch?

-Reinitializeall

RAM

YES

DEVICERESET

Stored

checksum

NORMAL

OPERATION

bq27500

bq27501System-Side Impedance Track™ Fuel Gauge

SLUS785 – SEPTEMBER 2007

When the bq27500 detects software reset ( [RESET] bit of Control( ) initiated), it determines the type ofreset and increments the corresponding counter. This information is accessible by issuing the commandControl( ) function with the RESET_DATA subcommand.

As shown in Figure 5-3 if a partial reset was detected, a RAM checksum is generated and comparedagainst the previously stored checksum. If the checksum values do not match, the RAM is reinitialized (aFull Reset). The stored checksum is updated every time RAM is altered.

Figure 5-3. Partial Reset Flow Diagram

Submit Documentation Feedback FUNCTIONAL DESCRIPTION 29

Contents

Main 1 INTRODUCTION 1.1 FEATURES 1.2 APPLICATIONS 1.3 DESCRIPTION bq27501System-Side Impedance Track Fuel Gauge bq27500 bq27501 2 DEVICE INFORMATION 2.1 AVAILABLE OPTIONS 2.3 TERMINAL FUNCTIONS 2.2 PIN DIAGRAMS 3 ELECTRICAL SPECIFICATIONS 3.1 ABSOLUTE MAXIMUM RATINGS over operating free-air temperature range (unless otherwise noted) 3.3 POWER-ON RESET 3.2 RECOMMENDED OPERATING CONDITIONS bq27500 bq27501System-Side Impedance Track Fuel Gauge 3.9 DATA FLASH MEMORY CHARACTERISTICS C-COMPATIBLE INTERFACE COMMUNICATION TIMING CHARACTERISTICS 3.10 I ADC (TEMPERATURE AND CELL MEASUREMENT) CHARACTERISTICS (continued) Page 4 GENERAL DESCRIPTION 4.1 DATA COMMANDS 4.1.1 STANDARD DATA COMMANDS Page Page Page Page 4.1.2 EXTENDED DATA COMMANDS Page 4.2 DATA FLASH INTERFACE 4.2.1 ACCESSING THE DATA FLASH 4.3 MANUFACTURER INFORMATION BLOCKS 4.4 ACCESS MODES 4.5 SEALING/UNSEALING DATA FLASH 4.6 DATA FLASH SUMMARY GENERAL DESCRIPTION18 Submit Documentation Feedback Table 4-7. Data Flash Summary (continued) 5 FUNCTIONAL DESCRIPTION 5.1 FUEL GAUGING 5.2 IMPEDANCE TRACK VARIABLES Table 5-1. Constant-Current Model Used When Load Mode = 0 Page Page Page Figure 5-1. BAT_GD Pin Operation, Based Upon Battery Presence and bq27500 Operating Mode Submit Documentation Feedback FUNCTIONAL DESCRIPTION 25 Page bq27500 bq27501System-Side Impedance Track Fuel Gauge 5.7.4 HIBERNATE MODE FUNCTIONAL DESCRIPTION28 Submit Documentation Feedback C command to the gauge. I 5.8 POWER CONTROL 5.8.1 RESET FUNCTIONS Submit Documentation Feedback FUNCTIONAL DESCRIPTION 29 Figure 5-3. Partial Reset Flow Diagram 5.8.2 WAKE-UP COMPARATOR 5.8.3 FLASH UPDATES 5.9 AUTOCALIBRATION 6 APPLICATION-SPECIFIC INFORMATION Page 7 COMMUNICATIONS 7.1 I C INTERFACE Page PACKAGING INFORMATION PACKAGE OPTION ADDENDUM Page Page Page IMPORTANT NOTICE