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bq77pl900: I2C Comm Error

Bobby Franklin
Prodigy 40 points
Part Number: BQ77PL900
Other Parts Discussed in Thread: EV2400

I have an ev2300 & ev2400 that I can't get to communicate with the IC. I have never been able to get a solid I2C Comm Status: OK indication. I've used 5 different PC's with different windows versions ranging from 10 to 7 with both 32 & 64 bit. I have verified that the ev2400 is working correctly and that the PCB's that I have are functioning correctly along with them being able to be programmed. I shipped them out to my old pack manufacturer that was able to program them with their equipment and my ev2400. When I open the bq77pl900 software without the USB plugged into the ev2400 I get an error message however I don't when it is plugged in so it seems that my PC's can see the unit. At different times I have been able to get I2C Comm Status: OK however it has flickered back to error and I can't load the firmware to the chip. 

  • 0
    TI__Guru 54715 points
    Hi Bobby,
    I did not expect the GUI would talk to the bq77PL900 using the EV2400. The software does not error with the EV2400 adapter but I get no I2C from the device. The EV2300 is the adapter supported by the GUI.
    Programming requires correct stable voltage, timing, and data/communication integrity.
    It seems your PCs must have the proper drivers or the adapter would not be found. It also seems the board design must work if your supplier was able to program. Check for contamination on the 4 pin cable or damaged wires. You might look at the I2C lines on the board and check for signal quality and periodic communication. If communication stops from the adapter it may be losing USB connection. The error message does not change from "ERROR" if the USB connection is lost. Check the USB cable.
  • 0 in reply to WM5295
    Prodigy 40 points

    I'm confused that you say the ev2400 won't work. Both the old battery pack manufacturer and the old PCB manufacturer are using the ev2400. The packs that I sent to the old pack manufacturer were programmed first on their ev2400 then mine, with my usb cable. I have three different usb cables and all three of the them give the same results. I do get I2C signal with the ev2300 however it is not stable and will flicker back to Error then back to OK. I have tried many many times to load the firmware with both the ev2300 and ev2400 with every attempt failed. 

    I have checked the 4 pin wires and have switched harnesses as well. How do I check for signal quality and periodic communication? 

    It seems that the problem is likely a software setting or something along that line, considering that my ev2400 would program packs on their PC however will not on any of the ones that I have. 

  • 0 in reply to Bobby Franklin
    Prodigy 40 points

    Did you download the "support components to enable specific TI sofware to work with the ev2400"? You won't have communication through the USB cable without it on the ev2400. 

  • 0 in reply to Bobby Franklin
    Prodigy 40 points
    OK, I pulled my ev2300 apart and found a bad connection to one of the I2C pins (clock). Now the ev2300 is loading the firmware however I still can't get the ev2400 to communicate. I have both the ev2300 and 2400 drivers and software loaded on the same PC, could this be the reason the ev2400 won't communicate. I did call and verify that the old pack manufacturer is using an ev2400 with the bq77pl900 software.

    I need to get back ordered production out so I will use the ev2300 to do so. If someone can help me sort out why the ev2400 is not communicating I will then have a back up unit if the 2300 stops working again.
  • 0 in reply to Bobby Franklin
    TI__Guru 54715 points
    Hi Bobby,
    Glad you have a working solution. The EV2400 uses different drivers than the EV2300, the "support components" should allow the bq77PL900 to find the adapter and work. I don't know why your communication is intermittent and mine does not work. I will continue to work this with software people and will post an update when available.