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IWR6843ISK: Undocumented response from bootloader

Scott Chandler1
Prodigy 50 points
Part Number: IWR6843ISK

I am following the Bootloader Flow document from here: http://www.ti.com/lit/an/swra627/swra627.pdf

When I put my mmwave board in flashing mode (SOP5) then go through the sequence to write a multicore image to SFLASH (UART BREAK {ACK}, OPEN {ACK}, WRITE {ACK}, ...etc), after sending the last WRITE command and awaiting the ACK, I then send the CLOSE command as per the documentation. The mmwave responds with a 0x0004 0x33 0x0033. This response is nowhere to be found in the documentation (though is suspiciously close to the ACK 0x0004 0xCC 0x00CC).

1 - Does 0x0004 0x33 0x0033 have a meaning? What is it?

I'm also confused about the fact that the documentation states that the device (mmwave) will calculate a CRC32 and "Ensure the CRC matches". 

2 - Matches what?

There is no mention of needing to append a CRC32 after WRITE commands. Except, the bootloader - UART section states "...The META IMAGE should not have the CRC32 appended (unlike the image to be flashed)."

The multicore bin image has many CRC's in it, one for the whole thing and one for each section, but it's made by the image creator tool so I'll assume it's correct.

3 - Do I need to append a CRC32 to something?

4 - If so, how?  What bootloader command is used (WRITE doesn't seem appropriate since I don't want it in flash)?

Thanks,

  • 0
    TI__Guru 50240 points

    Hi Scott,

    I've asked an expert to look into this and we should have an answer for you in the next few days.

     

    Cheers,

    Akash

  • 0 in reply to Akash Gondalia
    TI__Intellectual 800 points

    Hi Scott,

    The 0x4 0x33 0x33 is the NACK response from the device to the CLOSE command, indicating that the image integrity check has failed.

    The metaImage being flashed into the SFLASH needs to have a CRC32 (of the entire image) appended as the last 4 bytes. These bytes are used by the bootloader to check the image integrity during download.

    The bootloader only uses these last 4 bytes to check for the integrity and the CRC32 is not updated to the SFLASH.

    The Image Creator UserGuide in the mmWave SDK release mentions the image format needed for the SFLASH.

    Regards,

    Prathyusha Teja.I