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roger2399
Visitor II
November 5, 2003
Question

Linux + USB + STPC Atlas anyone got it working?

  • November 5, 2003
  • 6 replies
  • 1188 views
Posted on November 05, 2003 at 06:03

Linux + USB + STPC Atlas anyone got it working?

    This topic has been closed for replies.

    6 replies

    R
    roger2399Author
    Visitor II
    September 3, 2003
    Posted on September 03, 2003 at 05:29

    I can´t get this to work.

    The USB host is identified, power is turned on, but when connecting a device we run into problems.

    a) Device not accepting the address (USB-Serial, Memory)

    b) Device not detected (Microsoft Intellimouse - explainable wants Remote Wakeup)

    If you have this combination working please tell me:

    * What BIOS do you use (we use TinyBIOS - can be the problem)?

    * What Linux kernel? (we tried with 2.4.20)

    /RogerL
    S
    stephen239955_st
    Visitor II
    October 10, 2003
    Posted on October 10, 2003 at 11:37

    We hav done USB testing under Linux but maily on an older kernel (2.4.7). The device that was used was a mass storage device in the form of a Zip Disk.

    Normally, the BIOS does not configure the USB. It only initialises the PCI bridge and as a result initialises the USBbridge only. The USB is managed at driver level only.

    One detail that needs to be pointed out is that many drivers these days are compiled for Pentium machines and therefore do not work on the Atlas as it has a 486 class core. Therefore, there may be a problem at that level.

    Regards
    R
    roger2399Author
    Visitor II
    October 10, 2003
    Posted on October 10, 2003 at 12:46

    Good to hear!

    I will try 2.4.7 to see if it works.

    Suppose the BIOS setups PCI wrong...

    (that is why I like to know the BIOS type and version)

    I have compiled the kernel and its drivers myself.
    R
    roger2399Author
    Visitor II
    November 4, 2003
    Posted on November 04, 2003 at 09:56

    Solved: Was hardware issue!

    My attempt to describe it being a software person...

    Recent STPCs has ESD protection for USB internally!

    Remove your external protection otherwice you will get to little electrical driving ability.
    M
    marios
    Visitor II
    November 4, 2003
    Posted on November 04, 2003 at 10:16

    Hi RogerL,

    can you, or the colleague who worked on the fix, elaborate a bit more on this. It may help many people, and maybe avoid pcb revisions. thanks

    Felix

    R
    roger2399Author
    Visitor II
    November 5, 2003
    Posted on November 05, 2003 at 06:03

    OK, I have digged around abit. This is part of an answer we got from

    STPC Support

    ''Another possible point of investigation is to remove the ESD protections (USBDF0 1W5) as they have an inbuild capacitance that may affect the line impedance and just have the series resistor connected to the board.

    Note that the STPC already has its own ESD protections inbuilt to a level of 2000V Human body model.

    With reference to the Impedance problem in the Errata sheet, I suggest that you disregard this problem as it is an issue that is associated with the ESD protections and board design. At the time, we did not realise that the ESD protections had been included inthe STPC and we added them externally. This is why this issue is mentionned. To be honnect, it needs to be removed.''[sics]

    Our electrical engineers says this instead

    (Warning - translated by me, and I am not an electrical engineer...):

    ''ST Support writes about serial resistors but we use only 15k ohms termination resistors [agains ground]. It works and should be the

    correct way according to the USB specification.''

    Note: Early samples of Atlas like those on the evaluation board will never work since those processors do not have functional USB. We tried to change the processor on an evaluation board, but the board

    is very soft and got destroyed during desoldering of the old Atlas.
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