EV2400: BQ76942 and BQ34Z100-G1 sharing I2C bus, can only connect to BQ34Z100-G1

Monty Harding

Part Number: EV2400
Other Parts Discussed in Thread: BQ34Z100-G1, BQ76942, BQSTUDIO,

Greetings,

I have been able to successfully communicate/connect with both BQ76942 (I2C addr: 0x10) and BQ34Z100-G1 (I2C addr: 0xAA) via I2C using an EV2400 and BQstudio.

The problem I am currently facing is that I can only connect to the BQ76942 when the BQ34Z100-G1 is disconnected from the I2C bus. I can connect to the BQ34Z100-G1 when the BQ76942 is still connected to the same bus though.

The BMS board I am working with has both BQ chips on the same I2C bus, and the only way of disconnecting/reconnecting them is by desoldering/soldering 0-ohm 0402 links (this is currently the only method that works to connect BQstudio to the BQ76942).

When connected to the BQ34Z100-G1 I can use the 'Advancded Comm' tab to successfully send commands to the BQ76942 via I2C.

I have tried disabling 'Auto Detect at Launch' followed by manually selecting the BQ76942 to connect to, but the 'Auto Detected Device' still registers as '0100_0_16' which corresponds to the BQ34Z100-G1, and I get a warning dialogue saying that 'The selected device could not be found! [etc]' followed by the attached screenshot of the connection graphic. Interaction with the registers etc does not function correctly - it appears to be connecting to the BQ34Z100-G1 but trying to apply the BQ76942 register maps.

To clarify, I do not wish to connect to both simultaneously, I would simply like to select which chip to connect to for a single instance of BQstudio at startup.

Any assistance would be greatly appreciated!

Kind regards,
Monty

over 3 years ago

0 Shirish over 3 years ago

TI__Guru 57697 points

Hello Monty,

I am not sure this will work but it may be worth a try

1. Click on "Autorefresh is On". This will disable autorefresh and the text will be red

2. Now try to to detect with I2C addr 10 in the box below it and check if it detects bq76942

If this doesn't work, then see if data memory can be read correctly. Don't write data memory as it could cause corruption.

0 Monty Harding over 3 years ago in reply to Shirish

Prodigy 10 points

Hi Shirish,

Thanks for your reply and suggestion. Unfortunately this does not result in connecting to the BQ76942 and sometimes resulted in BQstudio entering a 'Not Responding' state. It does not appear as though data memory can be read correctly either. Please see screenshots below:

Kind regards,
Monty