Frequently Asked Questions about Soekris hardware

This page is all about Soekris embedded computers. Use it to keep track of frequently asked questions on the Soekris Tech mailing list.

Contents

  1. Searching
  2. Watchdog
    1. Does the Watchdog on the SC520 (net45xx) or SC1100 (net48xx) work under Linux?
  3. Boot issues
    1. Why do I see garbage on the serial console when I boot the board?
    2. I can't upgrade the BIOS
    3. How do I make it attempt to PXE boot on each reboot?
  4. Hardware
    1. GPIO
    2. USB
    3. Clock drift

Searching

To search the tech mailing list directly, google for this:

For example, suppose you wanted to know if it's possible to boot the 4801 from USB:

http://www.google.com/search?q=site:lists.soekris.com+usb+boot

Watchdog

Does the Watchdog on the SC520 (net45xx) or SC1100 (net48xx) work under Linux?

Yes, with kernel patches.

SC520 WD driver patch

SC1100 WD driver patch

Relevant mailing list posts:

Boot issues

Why do I see garbage on the serial console when I boot the board?

Soekris boards perform VGA emulation on the serial port. Some programs attempt to write to the serial and to VGA simultaneously, so you get confused output on the serial. Configure or patch your programs to use serial only. New versions of PXELinux (post v3.02) will do this for you if you specify CONSOLE 0 in your config file.

Serial-only patch for LILO 22.6.1: http://metrix.net/support/patches/lilo-22.6.1-novga.diff

Serial-only replacement for pre-3.02 PXELinux: http://metrix.net/support/pxeboot/tftpboot/pxelinux.0

I can't upgrade the BIOS

If download doesn't work for you from the boot prompt, try download - instead. Also, try a different Xmodem client (Minicom on Linux seems to work well.)

How do I make it attempt to PXE boot on each reboot?

First, go check soekris for the latest BIOS, it should solve this problem, if not, then keep reading The comBIOS currently stores the boot sequence in the 4 cmos locations at 0x21..0x24. 0x80 means the first harddrive, 0x81 mean the 2nd, 0xF0 is the PXE rom, 0FF is none.

The comBIOS will try booting starting with the value in location 0x21, and continuing with the next one if it fails.

For example, this will set it up to PXE boot first, then fail over to the flash if PXE fails: 

 > cmoswrite 21 F0 80 FF

 > cmoschecksum

 > boot

If something goes wrong experimenting with the cmos, you can always write some random value and reboot without doing the cmoschecksum. The comBIOS will then load it with defaults when the checksum fails.

Also, note that most empty CF modules come with a broken dos boot sector that does not return correctly, and therefore the comBIOS can not continue the boot sequence with a fresh empty CF module. Use dd to write some bits to the flash first to overwrite the broken boot sector.

Hardware

GPIO

The net4526 and net4826 GPIO header is on JP3. On the 4526, "JP3" is closest to the +3.3V pin. On the 4826, "JP3" is closest to the +5V pin. 

    +5     2     4    n/c
     O     O     O     O

   +3.3    1     3     5
     O     O     O     O

USB

The net4826 USB header is on JP6: 

        +5    USB-  USB+  GND
 JP6     O     O     O     O

Clock drift

Q: The clock on my box drifts wildly. What's up?

A: It's a hardware bug in the SC1100. Soren's comments:

http://lists.soekris.com/pipermail/soekris-tech/2003-September/018579.html

Patch against Linux 2.6.x to use the 27MHz timer instead of the TSC:

http://lists.soekris.com/pipermail/soekris-tech/2005-February/022671.html

The patch was originally written by Ted Phelps, and may be rolled into a future Linux 2.6 rev.

SoekrisFaq (last edited 2008-04-13 16:33:47 by localhost)