Home Forums Hardware discussions Serial over USB not working.

This topic contains 5 replies, has 2 voices, and was last updated by  biothundernxt 2 months ago.

Viewing 6 posts - 1 through 6 (of 6 total)
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  • #345

    biothundernxt
    Participant

    I am having trouble with my unit.
    I never could get the serial over usb to work with only the 5v power plugged in, it would show up as a device, but the terminal would stall.
    Plugging in the 12v power adapter yielded the desired result, but I was having problems getting it to read the sd card properly.

    Now, when I try to connect to the serial even with the 12v plugged in, I am having issues.

    It connects, but all I get is a >
    If I type anything (or nothing, it doesn’t matter) and hit enter, the console returns:

    E
    >

    Pressing the reset button makes it spit another > out after a moment, but then has the same behavior.

    If anyone has any insight as to what I am doing wrong, or if I perhaps have a malfunctioning unit, your insight would be appreciated.

    #378

    TheLinuxBug
    Participant

    Sounds to me (just guessing here) like you hosed u-boot on the SPI NOR chip. You should be able to place u-boot on an sd-card and boot from it. Once in u-boot on the SDcard you should also be able to re-load u-boot on the SPI NOR (assuming this is the issue). I am not sure if they have this process documented yet, but at least writing u-boot to an SDcard should allow you to boot into an operating system.

    Hope this helps!

    Cheers!

    #392

    biothundernxt
    Participant

    Thanks, I will try that.

    #393

    biothundernxt
    Participant

    Where might I get the uboot image for this board? I cant seem to find it on the wiki anywhere…

    #505

    biothundernxt
    Participant

    Update…
    entering ‘h’ or ‘?’ returns this block of text…

    
    >h
    h/? - print this help screen
    r yyyyyyyy - read register/memory at address yyyyyyyy in hex
    w yyyyyyyy zzzzzzzz - write zzzzzzzz to address yyyyyyyy in hex
    j yyyyyyyy - jump to address yyyyyyyy in hex
    x y - change the boot mode, where y is in hex
    a - UART control passed to AP CPU ROM
    c - UART control passed to CM3 CPU ROM
    

    Any ideas?…
    I also still have no idea what to do about a messed up U-boot, if that is what is going on… There is no info on the wiki on u-boot, and I am pretty new to anything more complicated than a raspberry pi when it comes to SBCs, so I am pretty used to the lazy “download a .img file and apply it to an sd card.

    I’m pretty confident in my ability to learn, I just need a point in the right direction, maybe a link to some articles explaining how this stuff works. Google has not been helpful at all in that respect.

    #508

    biothundernxt
    Participant

    Double posting due to lack of edit button… (why?…)

    I managed to find (by reading other threads) that there is an otherwise undocumented ftp site.
    ftp://downloads.globalscaletechnologies.com/Downloads/Espressobin/
    Has many useful files it would seem, including the U-Boot image.
    Now I just need to learn how to flash it.

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