LTC4015 Telemetry issues

Hello,

I am working on writing a firmware driver for the LTC4015 ic. The system charges x4 LifePo4 1100mAh cells @1A. 
The I2C seems to be working fine, it is ACKing the requests being sent to the device. 
However all the telemetry values like Vin, Vbat are not responding they are sending zero's.

To debug the device I bought the LTC4015 demo board and I removed LTC4015 IC and connected the demo board to the i2c pins of my custom board and intvcc to 5V output of LTC4015 on my board
.
The demo software opened normally and I was able to read all the values from the IC on my custom PCB design. 
I connected a digital signal analyzer to both devices and attached is a capture for debugging showing the I2C signals generated by my onboard microcontroller and that generated by the demo board. Both running at around 400KHz SCK frequency. 

Please note: that using my board I can read the number of batteries, and chemistry type normally. Also, I can read the MEAS_SYS_VALID bit. But not the voltage and current values.
Also, i cannot read the Charger status or System status.

Measurement Ready

Vin voltage

Using Demo board to read values from my custom board

System Status

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  • 0
    •  Analog Employees 
    on Aug 3, 2021 5:27 AM

    Hi hhazime,

    Hope you are doing well.

    Is your custom board based on the demo board of the LTC4015, DC2039A? If not, I suggest that you may want to take a look on it and try to differentiate, in terms of layout, the changes you made on your board vs the demo board. This is a good start on debugging since when you try to connect the I2C part of your board to the demo board, You were able to have a reading on the telemetry subsystem (such as the voltage and current values). Let me know what your findings on this.

    FYR, here is the link where you can get the design files for your board.

    DC2039A Evaluation Board | Analog Devices

    Regards,

    Siglo

Reply
  • 0
    •  Analog Employees 
    on Aug 3, 2021 5:27 AM

    Hi hhazime,

    Hope you are doing well.

    Is your custom board based on the demo board of the LTC4015, DC2039A? If not, I suggest that you may want to take a look on it and try to differentiate, in terms of layout, the changes you made on your board vs the demo board. This is a good start on debugging since when you try to connect the I2C part of your board to the demo board, You were able to have a reading on the telemetry subsystem (such as the voltage and current values). Let me know what your findings on this.

    FYR, here is the link where you can get the design files for your board.

    DC2039A Evaluation Board | Analog Devices

    Regards,

    Siglo

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