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Booting from FLASH

Jatin Pasrija
Intellectual 330 points

Hi


Till now I have been booting DM355 from NFS. Now I have transferred the contents to FLASH. I followed the steps given in A.5 (Getting started guide) and set bootargs as :

setenv bootargs 'mem=116M console=ttyS0,115200n8 root=/dev/mtdblock3 rw rootfstype=yaffs2 ip=10.20.21.15:10.20.21.12:10.20.1.1:255.255.0.0:::off'

This is the IP setting which had been working using NFS boot. The problem is that the FLASH boots correctly only when the serial port is connected to a computer. This is irrespective of which system I connect the serial port to. Can you please hep with the problem

Thanks

 

  • 0
    TI__Mastermind 37340 points

    I am not sure I understand your question.  The serial port is normally used to output the bootlog to determine the system booted properly.  On the EVM, data will still be sent there even when nothing is connected, but this should not prevent the EVM from booting.  Are you saying that when you do not have anything connected to the serial port, the system does not boot, but it works fine when a PC is connected to it?  Are you using our EVM or a custom EVM?

  • 0 in reply to Juan Gonzales
    Intellectual 330 points

    Hi Juan

    "when you do not have anything connected to the serial port, the system does not boot, but it works fine when a PC is connected to it" 

    Yes, this is precisely the problem I am facing. I am using the EVM that was shipped with the board.

    Thanks

    Jatin 

  • 0 in reply to Jatin Pasrija
    Intellectual 950 points

    hi jatin

     

    juan juan is right booting of the linux has nothing to do with the serial port it will boot whether the serial port is connected or not.turn on your board and connect the serial cable after the time it takes to boot you should get the prompt when you will connect the serial port.

     

     

     

    Regard's

     

    Rohan Tabish

  • 0 in reply to Roh@n T@bish
    Intellectual 260 points

    I am having the same problem with the dm365. I traced the problem to the fact that linux resets the PINMUX bits which the UBL sets to enable access to flash. I think you will need to make changes to the davinci drivers to reenable these bits.

     

    regards,

    Shlomo

     

  • 0 in reply to Juan Gonzales
    Intellectual 330 points

    Hi Juan

    I just realised that the board is booting correctly irrespective of whether or not I connect it to the CPU via serial port. However, the display on screen (the video output) is showing only if I connect the serial port to the CPU. More importantly, it works even if I only touch the the metallic outer surfaces of the serial port and the connector, and neither of the pins. Its some problem of common ground- is all I could come up with...

    Any solutions?

    Thanks

     

  • 0 in reply to Jatin Pasrija
    TI__Mastermind 37340 points

    Are you doing this on our DM365 EVM?  I just tried it on my EVM with DVSDK 2.10.00.18 and the board boots all the way regardless if I have a UART serial cable connected to the EVM or not.  The main difference is that when there is no UART cable connected, you have to keep in mind that the boot process will stop at the login prompt; but you can connect the cable back up and type "root" to login and get the prompt and you are good to go..

     [edit] Sorry, realized you were using DM355.  Just tried this on DM355 EVM with DVSDK 2.00.00.22 and got same behaviour as above.

  • 0 in reply to Juan Gonzales
    Intellectual 330 points

    Hi Juan

    I guess it is a very specific problem that has arisen out of some grounding faults. When I connect the metallic periphery of the serial port to the earth terminal of my power supply, the screen suddenly shows up. The boot process is not hindered at all, whether I connect the serial port or not. 

  • 0 in reply to Jatin Pasrija
    Intellectual 655 points

    I also had problems with ground and my video in/out. This is how i solved it

  • 0 in reply to Josef Kohler12051
    Intellectual 330 points

    Hi Joseph

    I hope I have understood your solution correctly.. You created a metallic plane, connected the ground of the board with this plane, and then connected the plane to the earth terminal (the 3rd pin) of the power input. Is this correct?

    Thanks

    Jatin

  • 0 in reply to Jatin Pasrija
    Intellectual 655 points

    Jatin Pasrija said:

    Hi Joseph

    I hope I have understood your solution correctly.. You created a metallic plane, connected the ground of the board with this plane, and then connected the plane to the earth terminal (the 3rd pin) of the power input. Is this correct?

    Yes thats correct. I also connected ground from all peripherials to the metallic plane.

  • 0 in reply to Josef Kohler12051
    Intellectual 330 points

    It seems my board has suddenly developed some snag. There was some noise in the video output. I touched the video-out ground and the display became perfectly clear and remained so even after I removed my hand. But after a few minutes the noise returned, this time more intense than before. And then the TV stopped identifying the output.


    This is how the problem has progressed:

    1. In the beginning, the board functioned without providing common grounding with the display

    2. Later, it displayed only if the screen and the board had common ground

    3. Now, it refuses to display even if I provide the ground.

     

    Any ideas how I can identify the problem? I checked the video-out using oscilloscope and there is some particular signal when the board is switched on, which means that the signal is being sent to the video-out, but somehow it is not able to take the load of the TV.

    Any clues? I've tried all I could think of...