BQ27GDK000EVM: GDK - I2C lines

leinho

Part Number: BQ27GDK000EVM

Hello,

I am planning to perform a battery characterization using the following EVMs: GDK and BQ27520EVM. After looking at the recommendations of the i2c connections in the GDK and due to the GDK's schematics appear blurred, I have the following questions:

- The BQ27520EVM has pull-up resistors but no jumpers to disable them. Should I desolder them then?

- Do both i2c lines in these boards use the same voltage? I can not tell this from the schematic.

Thanks for your help!

over 6 years ago

0 Onyx Ahiakwo over 6 years ago

TI__Guru* 76230 points

Hi Leinho,
No, no need to disable them. I have used that evm multiple times with the GDK

thanks
Onyx

0 leinho over 6 years ago in reply to Onyx Ahiakwo

Expert 1230 points

Hey Onyx, we have been having some issues setting the dev boards up and we found out that the i2c pull up voltage is different on each board: GDK works with 3.3 V and BQ27520EVM uses 2.5Volts.
Should not we need either a level translator or modify the GDK to use 2.5 Volts in the I2C lines?

Thanks.

0 Onyx Ahiakwo over 6 years ago in reply to leinho

TI__Guru* 76230 points

There is no need for a level translator. just use one voltage level either 3.3V or 2.5v

thanks
Onyx

0 leinho over 6 years ago in reply to Onyx Ahiakwo

Expert 1230 points

Ok, so I am going to remove the pull ups (R11, R12) in the BQ27520 and this should work. From your first question, I understood I should not do this and that's why I wanted to add a level translator.
By the way, do you have a better schematic files and layout for the GDK? The one that's in the user guide is blurred.

Thanks.

0 Onyx Ahiakwo over 6 years ago in reply to leinho

TI__Guru* 76230 points

4848.PWR568A_SCH.PDF

see attached

thanks

Onyx

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BQ27GDK000EVM: GDK - I2C lines