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OMAP-L138 Emulator Debug Boot

Boris Ruvinsky
Expert 1410 points
Other Parts Discussed in Thread: OMAP-L138

Dear E2E:

Thank you for your help.

I have  a question about Emulation Debug Boot.

In the document "Using the OMAP-L138 Bootloader"  (SPRAB41C) Appendix A "Emulation debug" and Section 3.3 "Emulation Debug Boot" describes the emulator connection to OMAP-L138.

It looks like the "boot bits" must be set to 0001 1110 before the Emulator is connected to JTAG.

Is this true?

We plan to boot from NOR FLASH in normal operation.

We don't plan to have any switches on PCB.

We can add some logic which is activated when the Emulator is plugged in.

Will this work?

We have boot bits set to NOR FLASH but when we connect the emulator - the boot mode switches to Emulator Debug mode.

Will it be OK?

This is a little surprising feature - we need to change the HW before connecting to JTAG interface.

Usually the processors do not require that.

Thank you for your help,

Boris Ruvinsky

  • 0
    TI__Mastermind 27585 points

    No, you can still connect to the ARM through JTAG without using emulator boot mode. You will have to manually wake up the DSP though (perhaps with a GEL file).


    We recommend having the pullup/pulldown resistor pads on your PCB in case you want to change boot modes easily in the future (such as UART boot).

    Jeff

  • 0 in reply to jc-ti
    Expert 1410 points

    Hello Jeff.

    Thank you for your respond.

    We have the pads for the resistors which can be changed.

    But we don't want to change them when we are connecting Debug Emulator.

    We have the resistors set to NOR FLASH.

    And we need to be able to connect to DSP (not to ARM) with emulator.

    Is it possible?

    What kind of GEL file we need to use?

    The GEL file is Emulator script as I understood. Is it correct?

    Thank you for your help,

    Boris Ruvinsky

  • 0 in reply to Boris Ruvinsky
    TI__Mastermind 27585 points

    If the DSP is running code out of reset, yes you will be able to connect. The only scenario where you will not be able to connect to the DSP is when it is in reset. In that case you can first connect to the ARM and run a GEL to wake up the DSP.

    The GEL file should come with the CCS setup files that you have downloaded.

    Jeff

  • 0 in reply to jc-ti
    Expert 1410 points

    Hello Jef.

    Thank you very much for your respond and help.

    Can you please give a little more details on the following questions.

    1.  I have "boot bits" set to NOR FLASH.

    2.  I have connected the emulator to JTAG connector.

    3.  I turn the Power on with emulator already connected to JTAG interface and "boot bits" set to NOR FLASH.

    4.  Will emulator be able to connect to ARM and DSP in this case?

    5.  Or I need to run the GEL file to wake up DSP? Wat GEL abbreviation means?

    6.  Who is reading the "boot bits"? I think it must be DSP. Is it correct?

    I am asking a lot of questions, probably. But unfortunately - the documentation is not very clear in many cases. And when you work on the HW design - you don't want to have a mistakes.

    Thank you very much for your help,

    Boris Ruvinsky

  • 0 in reply to Boris Ruvinsky
    TI__Mastermind 27585 points

    We're currently putting together better documentation to describe the boot process. Here is the current form:

    http://processors.wiki.ti.com/index.php/OMAP-L138_Bootloader

    In your case, if there is no image in the NOR flash, the the ARM bootloader will fail to complete. Therefore you will need to first connect to the ARM and wake up the DSP. Here are more details on the GEL format: http://processors.wiki.ti.com/index.php/GEL

    Jeff

  • 0 in reply to jc-ti
    Expert 1410 points

    Thank you, Jeff.

    Boris Ruvinsky

  • 0
    Expert 1150 points

    Boris,

    We found that we could not connect to the DSP if we were in NAND boot mode (for some unknown reasons) even with a GEL that would enable the DSP.

    I would advise you  to keep several boot  mode options (with jumpers) available on the board  other than the one you plan to use.

    We can connect to the DSP if we are either in HPI mode or emulator mode.

    Rgds

    KB

  • 0 in reply to KB2603
    TI__Mastermind 27585 points

    KB, I have not heard of anyone experiencing that problem with NAND boot. Did you have any image on the NAND or was it blank when this happened?

    Jeff

  • 0 in reply to jc-ti
    Expert 1150 points

    Jeff,

    If I recall correctly, the NAND was empty.

    We saw a problem trying to connect directly to the DSP with a GEL that would connect to it without using the ARM.

    If the L138 is set to boot in HPI or Emulator, then the emulator (USB510) can connect directly to the DSP and the GEL turn on the DSP.

    That seemed weird, but it works.

    KB

     

     

  • 0 in reply to KB2603
    TI__Mastermind 27585 points

    GEL files can only be run once the device has connected. Emulator boot mode will wake up the DSP automatically, but other boot modes do not. You should only expect to be able to connect to the DSP immediately after boot using Emulator boot mode.Otherwise, you have to connect to the ARM first and run the GEL.

    Jeff