BQ27500 IT_ENABLE issue

Hsin-hung Lin

Other Parts Discussed in Thread: BQ27500

Hi,

I'm using BQ27500 v1.30. According to the production flow, after I write the .dfi file to the gauge flash, IT_ENABLE command seems not working. QEN and VOK are still cleared in the CONTROL_STATUS. However, if I give some delay after writing flash and before IT_ENABLE command, around 2 seconds, it is ok. Is this the correct procedure of doint it? Thanks.

Shawn Lin

over 14 years ago

0 Charles Herder over 14 years ago

TI__Intellectual 2100 points

Yes,

You need to give a delay between writing the DFI and sending the IT_ENABLE command. I believe we generally recommend this delay to be 4 seconds.

Thanks,

Charles

0 Hsin-hung Lin over 14 years ago in reply to Charles Herder

Prodigy 40 points

Hi Charles,

Thanks for the information.

Is there any summary or documentation of this kind of needed delay for other commands or scenarios (if any) that I can reference. Thanks.

Shawn Lin

0 Charles Herder over 14 years ago in reply to Hsin-hung Lin

TI__Intellectual 2100 points

I would check out this app note for the typical delays needed in a programming sequence:

Going to Production with the bq2750x (Rev D) (Rev. D) (PDF 1294 KB)

The 4 seconds, however, is a boot time. When you finish programming, you are 'restarting' the gauge's firmware. I don't believe that this time is specified, as it is heavily dependent on interrupt timing. However, we have found that 4 seconds gives the gauge enough time to boot correctly.

Regards,

Charles

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BQ27500 IT_ENABLE issue