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bq27425-G2A / Calibration value in Hex

S.Satoshi
Guru 21685 points
Other Parts Discussed in Thread: BQEVSW

Hi Team,

Our customer would like to know the min/max/default value of calibration setting in Hex because they would like to compare the value which is read by bqEVSW or GaugeStudio.

I would like you to state the all value below in Hex.

  • 0
    Guru 21685 points

    Hi Team,

    I'm waiting for your response. Please let me know if you need more information.

    Best Regards,

    Sonoki

  • 0 in reply to S.Satoshi
    TI__Expert 4115 points

    Hello Sonoki-san,

    I have listed the way you can obtain the hex values for the calibration infomration for the '425-G2x.  I recommend using GaugeStudio for comparison as EVSW sometimes has some rounding issues causing the least significant byte can be a little different sometimes, especially when dealing with the CC Gain and CC Delta values.

    In the examples below the variable "var" is representative of value read from GaugeStudio or EVSW.

    CC Offset:  var = (x*4.7095) / 64000; where x = raw data value.  So, x = (var * 64000) / 4.7095, then convert x to hex

    Board Offset:  var = (x*4.7095)/64; where x = raw data value.  So, x = (var * 64) / 4.7095, then convert x to hex

    Int Temp Offset:  this is just an integer value offset that is formated.  So, just take the value in GaugeStudio or EVSW and shift the decimal to the right by 1 and then convert that raw value to hex.

    Pack V Offset:  this is just an integer value offset.  So, just take the value in GaugeStudio or EVSW and conver that raw value to hex.

    For the CC Gain and CC Delta values I have attached an application note (SLUA640A) that provides a flow to take a floating point value and convert to raw hex data.  The flow chart is on p. 8.

    CC Gain:  var = 4.7095 / x; where x = raw data value.  So, x = 4.7095 / var, then use x and follow the flow chart on p. 8 of the calibration document.

    CC Delta:  var = 5595388 / x; where x = raw data value.  So, x = 5595388 / var, then use x and follow the flow chart on p. 8 of the calibration document.

    4657.SLUA640A_mostRecentEdits.pdf

    I hope this helps.

  • 0 in reply to Jared Casey
    Guru 21685 points

    Hi Jared-san,

    I'm sorry for my delayed response.

    [Regarding Board Offset]

    Now I'm referring datasheet and it define the "Min -128(0x80), Default 0(0x00), Max  +127(0x7F)". But I tried to calculate it by using your formula and the result was "Min -9.419(0x80), Default 0(0x00), Max +9.3454(0x7F)". Can you confirm it and let me know if my understanding is not correct.

    [Regarding CC Offset]

    Referring datasheet and it define the "Min -32768, Default -1200, Max  +32767". I confirmed the default value by using bqEVSW and then it was 0xFA80. I calculated by using the value of 0xFA80 and your formula, and the result was -0.103609. Can you confirm it and let me know if my understanding is not correct.

    [Regarding default value]

    Can you confirm if the default value I listed is correct?

    CC Offset=0xFA80

    Board Offset=0x00

    Int Temp Offset=0x00

    Pack V Offset=0x00

    Best Regards,

    Sonoki