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BQ20Z80A-V110: Comm Register, firmware version and 5kΩ pull-up questions

Part Number: BQ20Z80A-V110
Other Parts Discussed in Thread: BQ20Z80-V102


My customer had three questions about the BQ20Z80ADBT device:

  1. Can we have access to the AFE comm register (or afe_fail count register) to know the number of communication failures that occurred so far?
    1. I couldn't find an answer to this in the TRM, can you help with this?
  2. bq20z80-V102: this firmware version is prior to the V110 that we are supposed to be using and it can create a communication failures as defined below (from bq20z80-datasheet). How can we check the correct FW version on the IC? Can we use TI Bq Gas Gauge Evaluation Software for that?
    1. Looking at the TRM on page 61 ( there are ManufacturerAccess commands and 0x0002 is for Firmware version. Is there a way to access this using Gas Gauge Evaluation Software?
  3. What if any impact would a 5kΩ pull up have on the clock and data lines of this chip.
    1. Reading the "SMBus Made Simple" application note it looks like 10kΩ is the recommended pull-up value. But looking at the datasheet it guarantees VOL of 0.4V with a 0.5mA output current for both interfaces. So another way to look at this is that the device is guaranteed to have the open drain output resistance of less than 800Ω (0.4V/0.0005A). At 3.3V with a 5kΩ resistor, the worst case output voltage should be 0.455V. Devices typically have 0.8V VIL thresholds so a little of the built in noise tolerance is lost (0.4 to 0.8V) but it should still work fine. I think the major thing is to make sure there is not another master ((second pull-up ) on the same bus where the pull-up resistors are in parallel. Do you agree?  

Please let me know if you have any questions and thanks in advance!