Updating Bq27220 Configuration Parameters; Gauge Mode Flashstream (Gm.fs) Files - Texas Instruments BQ27220 Technical Reference Manual

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User manual (20 pages)

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There are two ways the user can program custom configurations/profiles into the BQ27220 device:

1. Download the configuration/profile to BQ27220 RAM on power up.

The BQ27220 fuel gauge has RAM-based data memory parameters that can be updated if needed by

the host processor. This prevents external communication access to the fuel gauge to allow updating with

external tools. It may be useful that the application system main processor perform the actual firmware

updating, rather than having an external tool do it. The

export gauge mode FlashStream (gm.fs) files that can be used by the host to program the profiles in the

device RAM.

2. Download the configuration/profile to BQ27220 OTP.

On subsequent power cycles, the device uses the programmed profile for gauging. This appendix describes

the process of generating ot.fs files from BQStudio and using the SmartFlash tool to program the OTP with

the generated ot.fs file.

8.1 Gauge Mode FlashStream (gm.fs) Files

With the

Battery Management Studio (BQStudio)

gm.fs files, which contain the necessary I

the RAM-based data memory parameters. The commands in these files are largely ROM commands that can be

used only when the gauge is in CONFIG_UPDATE mode.

The gm.fs file is an ASCII text file that contains commands and data. Each line of the file represents one

command and potentially 96 bytes of data, as described in the following text. No row contains more than 96 data

bytes. The first two characters of each row represent the command, followed by a ":

"W:" — Indicates that the row is a command to write one or more bytes of data.

"C:" — Indicates that the row is a command to read and compare one or more bytes of data.

"X:" — Indicates that the row is a command to wait a given number of milliseconds before proceeding.

White space is used to separate fields within the gm.fs files. Each row contains only one of the four commands.

The commands discussed in this section can be implemented by a system that can perform multi-byte or

single-byte operations for I

Figure 8-1

shows a typical gm.fs file snippet generated from the BQStudio software.

SLUUBD4A – APRIL 2016 – REVISED NOVEMBER 2022

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