BQ40Z50-R2: SMBus address collision

Alexandre Massiot

Part Number: BQ40Z50-R2
Other Parts Discussed in Thread: BQ40Z50, BQ24725A

Hi,

I am working to interface preferably on the same SMBus, a BQ40Z50, its battery charger BQ24725A and two other smart batteries.

I am wondering how to do this address wise. From what I saw, there is a specification in the SMBus standard to use an ARP table to solve that issue.

But this table is only usable with SMBus 2.0 and above, and it seems that the BQ40Z50 does only support 1.1.

Do you know what could be done in order to have my MCU communicate with multiple SMBus system in that case?

Should the smart batteries and both BQ be on separated SMBus?

Thanks a lot for the help,

AM.

0 Andy Liu (BMS) over 5 years ago

As far as I know, the bq40z50 has a fixed SMBus address. The easiest way is that each one is connected to a separate SMBus.

Andy

0 Alexandre Massiot over 5 years ago in reply to Andy Liu (BMS)

Hi and thank you for your answer,

I will then look into that see whether it is possible in my case.

regarding the address, I could not find it on the datasheet, to you happen to know where I can find it?

Thanks.

0 Andy Liu (BMS) over 5 years ago in reply to Alexandre Massiot

Its 7-bit i2c address is 0x0b and its 8-bit i2c address is 0x16 or 0x17, depending on whether it is a read or write operation.

Andy

0 Alexandre Massiot over 5 years ago in reply to Andy Liu (BMS)

Hi and thank you again for your answer.

I was able to communicate with the smart battery, I was trying to use the 8bit address as a 7bit address so it obviously didn't work!

I was able to find the default address on the SMBus specifications that match the one you gave me.

Thanks again,

AM.

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