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CCS/TMS320F28335: Trouble reading Register Error 0x00000004/-1156

Part Number: TMS320F28335
Other Parts Discussed in Thread: UNIFLASH

Tool/software: Code Composer Studio

Hi All

I have a question about TMS320F28335. Recently we made 60 pieces of circuit board used TMS320F28335 as the main control chip. We found 10 pieces of circuit board couldn't download .out file to the chip. The schematic circuit diagram is a mature scheme, has already produced many batches, have not encountered such problems before, and all the circuit board made used the same schematic diagram. Due to the shipping demand, we replaced the main chip on the problem board with a new chip. Then everything was alright.

We left one piece of problem board for exception analysis.

We also resolder the welding if the welding is not good. But the problem is still there.

We do some test on input voltage 3.3V,1.8V and the external crystals signals. All the signals we tested is all right, the screenshot is shown as below.

The version of CCS we used is 3.3. Can you give me some advise on how to lock possible problem points? Thanks a lot.

  • Cooper,

    Sorry to hear that you are having problems.

    Do you have access to the XRSn signal?  Does it look stable?

    In the event that there might already be a password in the flash, you can try the following approaches from the datasheet:

    -Tommy

  • Hi Tommy
    I will try the method you provided.However, I still have a question. There is no encryption mode added in the software, and it is completely new chip from TI, will there be the possibility that the chip will be locked?
    Looking forward to your reply! Thanks a lot!
  • Cooper,

    I would not expect to find anything in the password locations, but there is always a very small possibility that there may have been some errant event either in TI or during your programming step that may have corrupted a word in the password location.

    The two debug approaches are also useful for bypassing generic issues that may lock out emulator access.

    -Tommy
  • Cooper,

                A new chip from TI has all flash locations (including the password locations) erased and hence comes unlocked. Are you saying your project does not have any passwords in the CSM password locations and yet it appears that the device is locked during the first programming attempt? Was there any kind of power-interruption, brown-out or current starvation during the programming process? Is this the setup you have used in the past?

  • Hi Hareesh
    Thanks for your reply!
    We don't have any passwords in the CSM locations and this setup has already been used in the past.
    This main control circuit boards is our matured product, we have used it in lots of our projects. Never meet this issue before.
    As the download process is done by workshop, I will confirm with my colleagues whether there was any abnormal interruption during the first time of download.
    Is there any default password if the download has been interrupted in the first time ?
  • No, there is no “default password” in such a situation. An interruption during the erase/program (E/P) process could leave the flash contents in an undetermined state. If this happens to the password locations, it could inadvertently lock the device, making it unusable. I presume you have scoped the VDDIO & VDD3VFL pins during the E/P operation to ensure the supply is clean.

    You may be aware that there is no support for CCS3.3. Have you considered moving to CCS8? If you do not want to change the tools environment (compiler/assembler etc), have you considered using Uniflash just for the flash programming part?
  • Cooper,
    Were you able to resolve this?