BQ40Z80: Program bq.fs file problem

YUXUAN CHIANG

Part Number: BQ40Z80
Other Parts Discussed in Thread: BQSTUDIO, EV2400

Hi,

We are currently supporting BQ40Z80, and we are trying to program the IC by ourselves.

There is a problem when programing. After programing the Flash (0x4000-0x5FFF), a read is required, as shown in the figure below for the location of SCW.

After Read, SMBus will be pulled low, communication cannot be performed, and programming is also stuck here.

I would like to ask whether there is a need to wait more or is there any command that needs to be executed when programing?

Or is there something in our circuit that needs to be modified?

Thanks

over 3 years ago

0 Shirish over 3 years ago

TI__Guru 57697 points

Hello Yuxuan,

X: 3 is a delay of 3 seconds. This delay is implemented before the referenced SMB command is sent.

SMB specification allows clock to be held low while the gauge is busy. How long is the clock line being pulled low?

0 YUXUAN CHIANG over 3 years ago in reply to Shirish

Prodigy 155 points

Hello Shirish,

The information I found is to wait for 3 milliseconds.

SMBus will always be pulled low after reading, and will not be able to communicate again until Vcc is reconnected.

0 Shirish over 3 years ago in reply to YUXUAN CHIANG

TI__Guru 57697 points

Hello Yuxuan,

Can you try programming this bq.fs file from bqStudio and see if you can reproduce it?

0 YUXUAN CHIANG over 3 years ago in reply to Shirish

Prodigy 155 points

Hello Shirish,

I have use EV2400 programing with the same file, but it works.

0 Shirish over 3 years ago in reply to YUXUAN CHIANG

TI__Guru 57697 points

Hello Yuxuan,

There may be some issue with the host software. I would recommend that you disconnect the communication lines when it enters the stuck state. Then check if host is holding the lines low or is it from gauge. The gauge implements SMB timeout and will release the lines.

0 YUXUAN CHIANG over 3 years ago in reply to Shirish

Prodigy 155 points

Hello Shirish,

So it is possible that the BQ40Z80 has released the SMBus, but our host side also pulls the SMBus down, so that will cause the communication to fail, right?

I will modify the software on the Host side and test it, thank you.

0 Shirish over 3 years ago in reply to YUXUAN CHIANG

TI__Guru 57697 points

Yes, that is possible.

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BQ40Z80: Program bq.fs file problem