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TMDSICE3359: Flash memories for start-up

Jani Soderstrom
Prodigy 240 points
Part Number: TMDSICE3359

Hi,
I'm trying to develop my own design based on TMDSICE3359 but the memory layout of Flash chips is causing some questions. I have erased the Beckhoff sw from the SPI Flash and I think I don't need such memory chip at all. And I don't need a Board ID Eeprom either due to only one possible board design and there will be only one dtb file in /boot of Linux rootfs. But I don't know should I have a NOR Flash in the design. Does the NOR Flash contain any part of the U-boot in the TMDSICE3359 design or does the FAT32 partition of the SD card contain all the U-boot?
I have a plan to have only an eMMC Flash in my design but if I need also a SD card connection for sw update in the production line, should these two use different MMC buses of AM335x? I think I could try to use some of the methods mentioned in https://e2e.ti.com/support/processors-group/processors/f/processors-forum/904467/processor-sdk-am335x-emmc-programming?tisearch=e2e-sitesearch&keymatch=am335x%20emmc%20programming for uploading the sw to the eMMC.
Regards,
Jani

  • 0
    TI__Guru 55285 points

    If you include an SD card option, the SD card should be connected to one of the MMC ports and eMMC should be connected to a different MMC port. You need to understand the ROM code boot requirements associated with MMC port assignments. For example, MMC0 supports booting from eMMC devices with less than 4GB of capacity while MMC1 supports booting from eMMC devices with 4GB capacity or greater.  Please refer to the Multimedia Card chapter and the Boot section of the Initialization chapter in the AM335x Technical Reference Manual for information on booting from eMMC/SD Cards.

    I will assign this thread to someone else that should be able to answer your U-boot software questions.

    Regards,
    Paul

  • 0 in reply to peaves
    TI__Guru 54455 points

    Hi Jani,
    Thanks for your interests on using AM335x in your design. A good reference on u-boot board porting
    software-dl.ti.com/.../U-Boot.html
    On your specific questions:
    As Paul mentioned in his earlier reply, it is possible to use both SD and eMMC as necessary in your design.

    Jani Soderstrom said:
    But I don't know should I have a NOR Flash in the design. Does the NOR Flash contain any part of the U-boot in the TMDSICE3359 design or does the FAT32 partition of the SD card contain all the U-boot?

    There's no dependency on NOR in general for booting from non-NOR boot media, where boot media (SD, eMMC, SPI...) is chosen by user.
    For example, it is ok to have all boot files (spl/u-boot/kernel/dtb/fs...) on two SD card partitions.
    Best,
    -Hong