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BQ20Z80-V102: issues. Led1 always lit. Chip crashes during calibration.

Part Number: BQ20Z80-V102
Other Parts Discussed in Thread: BQ20Z80, EV2400, BQ40Z50, BQ20Z80-V110, BQEVSW,

Good day TI,

I'm trying to bring up a battery pack using the bq20z80, using the software linked here:

I have an issue that LED1 is ALWAYS lit. Blank BQ20z80 powers up with LED1 lit. This is giving me issues calibrating current offset. If the battery is at 100% charge, and the display pin is pulled low then the leds ramp to all 5 leds on for a moment, then all the leds turn off for "LED HOLD Time"(4s) then LED1 turns back on.

Issuing a Display ON command(0x0034) turns the LED1 OFF. In other words, DisplayOn turns the leds OFF.

I'm also having issues while trying to calibrate current/current offset where the device would completely stop communicating. requiring complete power removal/restoration to reboot the chip.

During bqEASY programming, while it is uploading the setup to the chip it gets about 90% and then I get a "USB Timeout! Please check connections. For DFI read problem, verify device was never sealed". I get 4 or five of these errors at the end of upload.

Is this due to the V1.02 firmware? Old software?

If it matters, I'm using an EV2400 programmer.

Thank you,


  • Hello Errol,

    I would recommend that you use a newer gauge since there are many improvements and better documentation for the new gauges.

    Does the bqEasy software give warning messages related to detected device not being compatible?

  • Hi Shirish,

    In theory, yes, I should use a newer chip. Few, if any, are available. The ba20z80 is available. I was previously directed to rather use the BQ40Z50, which isn't available from Digikey nor directly from TI.

    Even the BQ20Z80-V110 isn't available in sample quantities from Digikey. So I'm stuck with the bq20z80

    No, neither bqevsw, nor bqEasy tells me that it isn't compatible. bqev start up, detects it as bq20z80 v1.02. The part number I order is BQ20Z80DBTR-V102.

    But if I allow bqEasy to write the default blank DFI file for bq20z80-v102 then the chip reports a DFF permanent failure.

  • Hello Errol,

    I understand.

    With a fresh bq20z80 chip, read out the senc file. You can program that file on any bq20z80 chip that shows DFF failure to recover it. This is a substitute for programming the default blank DFI which is more reliable.

    The bq20z80 is very old and the software was designed to work with EV2300. If there are any issues with the EV2400, we would not know it.

  • Thank you, yes, I did read out a fresh chip and saved the file.

    But I still don't understand why LED1 is fixed on, even before any programming.

  • Hello Errol,


    Operation Config A and LED Cfg (Subclass 67) determines the LED behavior

  • Thank you, I am aware of those registers. Nothing there, that I have found, can cause a led to remain on when the rest of the display turns off.

    Only way to turn led off is to send Display ON(0x0034) command. But it turns back on the moment I send any other command.

    All I can assume now is that the parts that Digikey stocks is either counterfeit, or defective, as I have replaced the chip and get the same result.

  • Couple of suggestions:

    1. Verify that the permanent fail register is not set.

    See 2.5.4 Permanent Failure Error Codes

    2. Compare your schematic to the EVM. Or use an EVM and see if the observation is the same. The EVM is the best reference point to rule out any other issues.