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TPS26750: Boot configuration

Mihkel Türnpu
Prodigy 20 points
Part Number: TPS26750
Other Parts Discussed in Thread: TPS25750, TPS55288, BQ25756

Tool/software:

Hello!

I'm having a problem with sending a full flash binary via I2C to the TPS26750 PD-controller. It accepts the patch but won't go into APP mode after receiving it and stays in BOOT mode. 
Also when using the GUI provided by TI, the generated array in .c file is called TPS25750 array instead of TPS26750. Is this something to look into? Any help would be appreciated!
Mind that I'm new to programming and using ChatGPT as my main source of aid.



  • 0
    Prodigy 20 points

    I switched to trying to send a low reg binary. When I read from the mode register right after power-up, it says "?PTC" but if I skip the first byte and read it then says "PTCH".  Is it normal that the first bit is nonsense (0x04)?

  • 0 in reply to Mihkel Türnpu
    Prodigy 20 points

    Reading the ptch start status it says 0x40 which is also nonsense.

  • +1 in reply to Mihkel Türnpu
    TI__Mastermind 37855 points

    Hi Mikhel,

    The first byte indicates the number of bytes that should be read in the register. Please look in the TRM at figure 1-3.

    Don't worry about the array name, if you are generating using the GUI after selecting TPS26750 as the device, you should be fine.

    Can you share the json you are using?

    You mentioned you are generating a .c file, are you following the PBMx programming sequence described in the TRM?

    Is this on customer HW or on and EVM?

    Thanks and Regards,

    Chris

  • 0 in reply to Christopher Lim1
    Prodigy 20 points

    Hi Christopher!

    Thank you for answering!

    I'll add the json. 5758.TPS26750 settings.rar
    I tried following the sequence in TRM but I'm afraid I'm doing something wrong code wise. It is a customer HW not an EVM. 

    I'm using two TPS26750 PD controllers and both have constant 3V3 supply and also a 5V supply on PP5V. The external power-paths are supplied by TPS55288Q1. I'm using STM32Q4 series as an EC and not using EEPROM. 

  • 0 in reply to Mihkel Türnpu
    TI__Mastermind 37855 points

    Hi Mihkel,

    In order to flash the device over I2C (EEPROM-less), you need to follow the PBMx sequence in section 5.2 of the TRM, specifically the flow-chart shown.

    Are there any parts of the sequence that you are having difficulties with?

    Can you share an I2C log of the entire PBMx transaction? I can try to review it and provide feedback.

    Realize that the TPS55288 does not support EPR voltages, and only goes up to 21-V. Also, for EC controlled systems, we currently have limited support and documentation. We typically recommend customers use the BQ25756 with the TPS26750.

    I sent you a friend request. Could you share your schematics over private message with me so I can review them? It is more secure than this public forum. I'll continue to help with debug here, but we can keep the schematics private.

    Thanks and Regards,

    Chris

  • 0 in reply to Christopher Lim1
    Prodigy 20 points

    TPS Mode = PTCH
    [PATCH] Starting patch upload sequence for 0x21...
    [PATCH] DATA1 = 40 80 33 00 00 50 32
    [PATCH] CMD1 = 04
    [PATCH] Output DATA1 = 40 00 00 00 00 50 32
    [PATCH] PBMs acknowledged. Uploading patch to 0x50...
    [ERROR] Failed patch write (second burst)
    [ERROR] Sending PBMe...
    [PATCH] PBMe sent, patch upload sequence stopped!
    [PATCH] DATA1 = 40 03 00 00 00 50 32

     

    This is the I2C log I have.

    I am using max 20V @ 5A so it should still be in tps55288 range, no?

  • 0 in reply to Mihkel Türnpu
    Prodigy 20 points

    For the log above I sent patch over in two bursts and it never accepts the second burst.

    Now I tried sending in 4 bursts and it sends 2 and then stops so again only half of the patch is sent. Is there a good explanation for that?

  • 0 in reply to Mihkel Türnpu
    Prodigy 20 points

    I finally got the patch to upload by changing the timeout to 0x64 instead of 0x32.

  • 0 in reply to Mihkel Türnpu
    TI__Mastermind 37855 points

    Hi Mihkel,

    I'm not too sure what you are saying here. The bursts were nacking and by increasing the timeout value, it started acking?

    How long would you wait after the PBMs command to start sending the bursts?

    Can you confirm the device entered APP mode? (if you read the mode register 0x03)? If you are able to get this working, then you should be good to go.

    Thanks and Regards,

    Chris

  • 0 in reply to Christopher Lim1
    Prodigy 20 points

    Yes, the device entered APP mode. I think I had a delay between sending PBMs to cmd1 and reading data1 to confirm start status. The TRM says to always use 5 second timeout (0x32) when sending the PBMs but it timed out during the patch burst before it could complete. Maybe the problem was a mix of low I2C frequency and an unnecessary delay? 

    Thanks,

    Mihkel