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BQ76940EVM: A read of data written failed comparison

Kyle Ferreira
Prodigy 100 points
Part Number: BQ76940EVM
Other Parts Discussed in Thread: BQSTUDIO, BQ76940, BQ78350, BQ78350-R1

I have a bq76940EVM I am trying to use to monitor a battery pack. When I attempt to change the AFE cell map I get the error "a read of data written failed comparison". I am am using a Ev2300 that works with the evaluation software and shows all cell voltages. But when I use bqStudio only one cell voltage is shown. I get this error whenever I try to write to data memory. 

I also attempted to change my cell chemistry and with that I get error "1470".  I currently am running firmware version 0x0006 and hardware version 0xAA. 

  • 0
    TI__Guru 54715 points
    Hi Kyle,
    The default cell configuration is 3 cells. You will need to get those 3 cells powered and to display voltage before the gauge is likely to allow any updates. You may have sufficient voltage applied to the board, but if it can't see the cell voltages it won't allow updates. See the bq76940EVM user guide and of course the bq76940 data sheet section on connecting cells. Starting with a power supply and the on-board cell simulator should be much easier than going directly to cells.
    Once you have the 3 cell voltages displayed we would recommend updating the firmware. Version 0x0103 is the current production firmware, it is available from the bq76930-R1 product folder.
  • 0 in reply to WM5295
    Prodigy 100 points
    I had three cells showing at one point, and i attempted to follow the user manual to change that number to 15 i am unable to write to data memory. The evaluation software sees all 15 voltages and they are all around the same value so i know the board can see them, but bqstudio doesnt allow me to change the afe cell count.
  • 0 in reply to Kyle Ferreira
    TI__Guru 54715 points
    Hi Kyle,
    If the bq76940 evaluation software shows cell voltages for all cells you probably have good connection. Do not attempt to run both softwares at the same time or the bq76940 software with the gauge.
    You don't indicate the value of AFE Cell Map, but indicate 1 cell, so it is probably 0x0001. If this is the case the ADC will not allow a high enough value of a single cell to meet the data flash write value. You will will be locked out of configuration changes and will need to re-program firmware. Find the firmware file for bq78350-R1 on the website and program the part. Restart bqStudio after programming, then set parameters. Be sure the bq76940 software is not running when programming, configuring, or running the bq78350.
  • 0 in reply to WM5295
    Prodigy 100 points
    I am attempting to download the firmware for the bq78350-R1 and I am getting a "Gateway Anti-Virus Alert" and I am unable to download. I tried to do this on multiple computers. Is this a problem on my end or yours? and is it possible to have the firmware emailed to me directly?
  • 0 in reply to Kyle Ferreira
    TI__Guru 54715 points
    Hi Kyle,
    It downloaded with no problem, might have been fixed or is on or your end. There is a link on the download page for assistance. I'm not allowed to email it.
  • 0 in reply to WM5295
    TI__Guru 54715 points
    Hi Kyle,
    I have not heard from you for a few days. I hope the download people were or are able to assist you, sometimes web things take time. I will close this for now.