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Reading SM-Bus from bq78pl114 with I2C device

Lars D
Prodigy 80 points

Hi there,

I have a problem with a task which started to look simple but figured out to be "heavy". 

We have a Batterypack with the bq78pl114s12 and need the SoC, Current and Voltage of this unit on an RS-485 Bus for further hardware.
We have a Controllboard with RS-485 and I2C and want to use this. (It has an Atmel Controller so I'm mot asking in the Controller section )

First the simple test: Sending device adress with write, sending the instruction byte, sending the device adresse with read  wait for the bytes.

I get an ACK for the first 3 Bytes but no Data is send byte the BQ. Attached is a picture with a comparison of the communication from the USB Interface from TI (top Line)
and our one (Bottom Line)

  

Because I have to but it together from different Screens the Distance between the Bytes are not correct.  The largest distance is  550µs between "device adresse and read" and the clock for the bytes to come. 

Does anyone who has already such a system running a solution?.  Clockstrechting is allowed by the controller but it seems to be not used by the bq. 

Any hint will be welcome! :)

 

Thx for now.

  • 0
    Prodigy 140 points

    Hi,

    I  have doubt about your program and it is very important to write the correct program and communicate with the bq using RS485.Additionally,the SCI agreement does not  compatiable with the IIC.  Aso we should adapt the only address.Did you use C/C++  language programing and should I have a look at your program?

     

    Thanks

    Randy