BQ32002: I2C Bus Problems

Sebastian Ivenz

Part Number: BQ32002

Hello,

we use the BQ32002 module in our application.

At the moment we can switch on all I2C modules separately. This is done with the help of a switch on the SDA line. As soon as we connect the BQ32002 module, the bus voltage collapses.

Do you know this problem and have a solution for it.

Best regards

Sebastian

over 4 years ago

0 Lane Boyd over 4 years ago

TI__Genius 16845 points

Hi Sebastian,

I haven't seen this issue before with BQ32002. Do you observe this on multiple devices and systems? Is the I2C communications meeting the requirements in datasheet table 6.6?

One thing to be aware of is that the time-keeping registers are not updated when the BQ32002 is operating from the backup supply. Please make sure that VCC is powered up if you need to access BQ32002 registers.

Kind regards,
Lane

0 Sebastian Ivenz over 4 years ago in reply to Lane Boyd

Prodigy 20 points

Hi Lane,

the problem is on multiple devices. At this time we use the standard mode from I2C.

The main problem is that we could not communicate with any I2C slave while the SDA line is connected to the BQ32002.

It does not matter whether we switch on VCC or not, as soon as the SDA line is connected to the bus, the voltage breaks down or communication with a slave can no longer be made. This problem does not exist with an RTC module from Maxim.

We also check the timing requirements again

Kind regards,

Sebastian

0 Lane Boyd over 4 years ago in reply to Sebastian Ivenz

TI__Genius 16845 points

Hi Sebastian,

I will look into this I2C communication issue further with the backend team to see if we can discover more about what is going on.

This means that when BQ32002 connects to the SDA line, it forces SDA low, correct? And BQ32002 never releases SDA back high?

Please send and email to cts_rtc_nt_flex@list.ti.com and we can continue our discussion offline

Kind regards,
Lane

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BQ32002: I2C Bus Problems