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DM816x UART boot xmodem - baud rate divider set by ROMcode - PG2.0 silicon revision

Lo
Expert 3020 points


Hello,

there is a known bug that UART boot (xmodem protocol) does not work on PG 1.0/1.1 silicon with a regular baud rate due to a wrong divider selection by romcode:

Advisiory 1.1.21: http://www.ti.com/lit/er/sprz329d/sprz329d.pdf

The errata shows that this bug should not be present on a PG2.0 silicon revision, still the baud rate does not seem to match 115200 Bd. The crystal used has a frequency of 27MHz, the generated Baudrate is different from the one described in the errata but still not correct.

Can you please check the baud rate when booting over UART?

Best regards,

Lo

  • 0
    TI__Guru**** 170625 points

    Hi Lo,

    The PSP/u-boot in the latest EZSDK 5.05.02.00 does not support UART boot for DM8168 device.

    You can check the possible boot options for DM8168 in the link below:

    http://processors.wiki.ti.com/index.php/TI81XX_PSP_U-Boot#Building_U-Boot

    Are you trying to develop the "UART boot" feature yourself?

    Regards,

    Pavel

  • 0 in reply to Pavel Botev
    TI__Expert 3020 points

    Hi Pavel,

    this is about the romcode loader, which load the first stage bootloader (MLO), so way before u-boot is active.

    See TRM 25.8.6 UART boot procedure.

    Regards,

    Lo

  • 0 in reply to Lo
    TI__Expert 3020 points

    Hello Pavel,

    the bootmode used is : 10111 (sd/spi/uart/emac).

    Regards,

    Lo

  • 0
    Intellectual 560 points

    We use 64904 baud to boot from the ROM code on silicon >= 2.0, and it works.  (This is still incorrect, and exactly double the 32452 value found on silicon <= 1.1.)

    Hope this helps,

    - Mark

  • 0 in reply to Mark Thompson
    TI__Expert 3020 points

    Hi Mark,

    thanks for the information.

    Which bootmode do you use?

    Maybe it's related to the bootmode settings?

    Regards,

    Lo

  • 0 in reply to Lo
    Intellectual 560 points

    Hi,

    The 64904 value is with boot mode 00010.  (Used on both 2.0 and 2.1 silicon, in case that's relevant).

    - Mark

  • 0 in reply to Mark Thompson
    Expert 1985 points

    Hi All,

    We have a requirement of flashing the boot loader code through UART interface. In this regard i have the following question,

    1. Which application has been used to send boot loader data to the board at 64904 baud rate?

    2. I believe that if the boot mode pins are set to 10010 (NAND - primary boot), it should still boot from UART as it is the fourth boot mode. Kindly confirm.

    Thanks & Regards,

    Khader Shareef

  • 0 in reply to Shareef
    Intellectual 560 points

    Hi,

    Khader Shareef said:

    1. Which application has been used to send boot loader data to the board at 64904 baud rate?

    We wrote our own application for this purpose, using an FT232R-based dongle along with libftdi which offers full control of the baud rate.  I don't know what other chips and/or applications can be configured to do this.

    Khader Shareef said:

    2. I believe that if the boot mode pins are set to 10010 (NAND - primary boot), it should still boot from UART as it is the fourth boot mode. Kindly confirm.

    This is correct.  Note, however, that once it has committed to booting from NAND (a valid image is found), there is no way out to boot from UART instead if that image is faulty somehow.

    - Mark