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AM3358: SPL/UBOOT has long boot delay

Justin Na
Prodigy 30 points
Part Number: AM3358

Hi everyone,

I am trying to bring up(porting) our custom board which based on BBB. But SPL/UBoot has some delay, like this. (always same delay)
Anyone experience this phenomenon or give me advice.

case1: UART boot
CCCCCCCC - (20sec pause) - CCCCCCCC - (20sec pause) - CCCCCCCC - (20sec pause) ...

case2: eMMC / uSD boot
(2min 30sec pause) - first SPL log at debug port

Thanks in advance
Justin

  • 0
    TI__Guru 68430 points

    Hi Justin,

    1. AM335x boot order:

    AM3358 boot sequence depends on the on-board SYSBOOT pins setup. A good reference on how boot order is determined by on-chip rom code via SYSBOOT pin is detailed in the Chapter 26.1.6 <Booting> in the AM335x TRM

    https://www.ti.com/lit/ug/spruh73q/spruh73q.pdf

    Once the booting device list is set up, the booting routine examines the devices enumerated in the list sequentially and either executes the memory booting or peripheral booting procedure depending on the booting device type. If the memory or peripheral booting fails for all devices enumerated in the device list then the ROM Code gets into a loop, waiting for the watchdog to reset the system.

    2. BBB default boot order:

    A detailed description on BBB boot configuration, and default boot options are referenced here

    https://github.com/beagleboard/beaglebone-black/wiki/System-Reference-Manual#67-boot-configuration

    https://github.com/beagleboard/beaglebone-black/wiki/System-Reference-Manual#68-default-boot-options

    Best,

    -Hong

  • 0 in reply to Hong Guan64
    Prodigy 30 points

    Hi Hong,

    Thanks for the prompt reply with a detailed explanation.

    However, I am still debugging this issue because it has not been resolved. (delay issue)
    I've been checking and comparing the checklists you gave me, but I haven't found anything strange yet.

    For reference, it is my SYSBOOT Configuration Pins setting and schematics (it is the same as BBB)
    1. SYSBOOT[4:0] = 11000b: SPI0 -> MMC0 -> USB0 -> UART0 
    2. SYSBOOT[4:0] = 11100b: MMC1 -> MMC0 -> UART0 -> USB0

    In my case, there is a 20-second delay in the middle of the output  "CCCCCCCC".

    In other reference boards, "CCCCCCCC" is output without delay.

    Is the boot sequence repeating or not?

    For example SPI0 -> MMC0 -> USB0 -> UART0 -> SPI0 -> MMC0 -> USB0 -> UART0 -> SPI0....

    Best regards

    Justin

  • 0 in reply to Justin Na
    TI__Guru 68430 points

    Hi Justin,

    I tested with SYSBOOT[4:0]=11000b on TI EVM, the continuous "CCCCC..." output on serial terminal.

    I'm not able to explain your observation.

    Justin Na said:
    In my case, there is a 20-second delay in the middle of the output  "CCCCCCCC".

    Will you be able to boot up to u-boot prompt?

    if yes, can we read SYSBOOT from CONTROL_STATUS register via "md.l 0x44E10040 1"

    Best,

    -Hong

     

  • 0 in reply to Hong Guan64
    Prodigy 30 points

    Dear Hong

    Thank you for your tip.

    Hong Guan64 said:

    Will you be able to boot up to u-boot prompt?

    if yes, can we read SYSBOOT from CONTROL_STATUS register via "md.l 0x44E10040 1"

    This is a result. I think SYSBOOT pins are correct according to Figure 9-5.

    MMC boot:

    008103fc = 0000 0000 1000 0001 0000 0011 1111 1100

    SD boot:

    008103f8 = 0000 0000 1000 0001 0000 0011 1111 1000

    BR

    Justin