bq2019

ADVANCED BATTERY MONITOR IC

SLUS465E – DECEMBER 1999 – REVISED FEBRUARY 2003

21

POST OFFICE BOX 655303

ERRATA

Issue : This errata ONLY applies if page 1 (address 0x20– 0x3F) or page 2 (address 0x40– 0x5F) of the

embedded flash memory is read through the HDQ interface. If your specific application or method of use

does not involve reading from any location on page 1 or page 2 of flash memory, please disregard this

erratum.

Description:

This errata ONLY applies if page 1 (address 0x20– 0x3F) or page 2 (address 0x40– 0x5F) of flash memory is

read through the HDQ interface. Under rare conditions, the read operation may return 0xFF data for locations

on page 1 or page 2. However, this is only an issue with the READ operation. There is no impact on the content

or the integrity of the data stored in page 1 or page 2 of the flash memory.

This document also describes two simple methods of safeguarding against this condition. Both methods are

implemented on the host system software. No hardware modifications are required.

Safeguarding Method Number One:

This method ONLY applies if the user does not ever write to any location on page 0 (0x00–0x1F). This method

uses a flash to RAM transfer sequence in order to clear any potential read issues.

Yes

Proceed. No action

required.

Write data 0x48 to

address 0x62

(FCMD=0x48)

Read desired address in page 1 or

page 2. Data is valid.

Accessing page 1 or

page 2

No

Did you read data 0xFF

from a location on

page 1 or page 2?

Figure 1. Procedure Flow for Safeguarding Method Number One

Safeguarding Method Number One:

For all applications that write to page 0, please proceed to Safeguarding Method Number Two.