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bq24250 i2c problem

Other Parts Discussed in Thread: BQ24250, BQ25890H

Hi,

I have some problems to communicate with bq24250RGE. The device never send ACK when the MCU sends the address. (I'm using 0x6A).

I checked all the connections. Also I used a logic analyzer to verify the i2c data, but it is fine.

The SCL line is running at 10Khz and the signal wave has a very good shape.

Other tests I have done:

> I connected VIN and I could verify that I get a good VSYS output (The switching is working ok). In this condition the i2c still not working.

> When put CE to ground, I don´t see any response on STAT pin or INT pin, but I still have a good output on VSYS. The battery current on this situation is zero.

> When I connect and disconnect VIN, I have a  pulse on INT pin. This pulse has 250us width.

What other test do you recommend to verify the proper device functioning?.

See attached the schematic I'm using.

Thank you in advance.

Best Regards.

Lucas

  • Hello, Lucas,

    Do you have a battery connected when you did the above tests and what was the battery voltage? Also, from your schematic, /CE is pulled high, can you double check if you've grounded /CE during the test?

    - Please check if LDO is coming up when you apply VIN

    - What is the value of R2 and R3 that are connected to VDPM? If R3=0, it is not correct.

    - Please make sure the TS resistors are correct based on the attached calculation sheet.

    - You can try shorten the SDA and SCL lines and see if it has any difference

    Thanks,

    Wenjia

    7635.Thermal TS bq2425x Cal Tool.xls

  • Hello Wenjia Lui,

    Apologies for not replying sooner.

    Problem solved!.

    I have made two mistakes.

    1) I was using a wrong address. The datasheet say that the address is 0x6A, but I forgot to rotate one step to the left, so the true address is 0xD4.

    2) Using I2C, I realised that I was having a battery temperature fault. My NTC was not connected, so it's like the battery was frozen to the system.

    The device is working wonderful now.

    Thanks for your help.

    Best Regards

    Lucas

  • can you please upload to here your final schematic that working  

    thanks

    yaniv

  • can you share the code of bq24250 i2c
  • Hey manoj,

    We do not have a specific code written for the I2C implementation with the bq24250.

    However, there is a TI-Design that has code written for communication with the charger. This code is easily transferable and modifiable for the bq24250.

    TIDA-03029 - This code is tailored for the bq25890H, but the I2C interface is similar. The register map will be different as will the application use.

    I should also say that the I2C protocol is pretty standard, so any implementation of it should work with the bq24250, provided you address the registers as we state in the datasheet. 

    Check out the MCU e2e forum for more info on implementing I2C.

    Hope this helps,

    Joel H