As soon as the USB-to-serial port port is plugged into the laptop, the laptop should show it when listing USB devices:
lsusb
<...>
Bus 001 Device 110: ID 067b:23a3 Prolific Technology, Inc. ATEN USB to Serial Bridge
<...>
On my laptop, that shows up as /dev/ttyUSB3
:
sudo journalctl --grep ttyUSB
<...>
Jul 02 10:06:01 mycroft kernel: usb 1-4.1: pl2303 converter now attached to ttyUSB3
With the Soekris wired up, we can try to access its console using minicom. (In case it's not installed: sudo apt-get install minicom)
Before a non-root user can use minicom, the user should be a member of group 'dialout', so edit /etc/group
, or use addgroup.
Use id to check that the membership has taken effect.
If it has not, start a new shell so that it may.
The minicom interface takes a bit of getting used to. CTRL-A Z can be used to access the menu.
Then choose 'O' and then 'Serial port setup' to make minicom use /dev/ttyUSB3
, or whatever device represents your USB-to-Serial converter:
+-----------------------------------------------------------------------+
| A - Serial Device : /dev/ttyUSB3 |
| B - Lockfile Location : /var/lock |
| C - Callin Program : |
| D - Callout Program : |
| E - Bps/Par/Bits : 115200 8N1 |
| F - Hardware Flow Control : No |
| G - Software Flow Control : No |
| H - RS485 Enable : No |
| I - RS485 Rts On Send : No |
| J - RS485 Rts After Send : No |
| K - RS485 Rx During Tx : No |
| L - RS485 Terminate Bus : No |
| M - RS485 Delay Rts Before: 0 |
| N - RS485 Delay Rts After : 0 |
| |
| Change which setting? |
+-----------------------------------------------------------------------+
It's also necessary to let both sides of the serial connection use the same parameters: baud rate and parity. The relevant menu can be reached via CTRL-A Z P (or via CTRL-A P), and mine looks like this:
+---------[Comm Parameters]----------+
| |
| Current: 115200 8N1 |
| Speed Parity Data |
| A: <next> L: None S: 5 |
| B: <prev> M: Even T: 6 |
| C: 9600 N: Odd U: 7 |
| D: 38400 O: Mark V: 8 |
| E: 115200 P: Space |
| |
| Stopbits |
| W: 1 Q: 8-N-1 |
| X: 2 R: 7-E-1 |
| |
| |
| Choice, or <Enter> to exit? |
+------------------------------------+
If these parameters are not properly set, minicom may give some output, but usually with many (or exclusively) unreadable characters. Unless you already know which settings the Soekris is using, some trial-and-error will be involved.
It may be necessary to reset the Soekris when retrying with new serial port parameters. That can be done with a paperclip through the 'reset' pinhole. If all goes well, something like this may be seen:
POST: 012345689bcefghips1234ajklnopqr,,,tvwxy
comBIOS ver. 1.33 20070103 Copyright (C) 2000-2007 Soekris Engineering.
net5501
CPU Geode LX 500 Mhz
0000 Mbyte Memory
0512
Pri Mas SILICONSYSTEMS INC 4GB LBA Xlt 1023-128-63 4125 Mbyte
Pri Sla INTEL SSDSA2CW120G3 LBA Xlt 1024-255-63 117 Gbyte
Seconds to automatic boot. Press Ctrl-P for entering Monitor.
Once the minicom settings are right, save them. Save-as-default is in minicom's 'configuration' menu: CTRL-Z A O.
You can see above that this Soekris has two disks. We can press CTRL-P to access the Soekris' BIOS. Note that we can change its serial port settings there too. If you do, better change them in minicom too.