LBOX
December 13, 2004
Quick HOWTO: Telnet, TFTP and XINETD
The above link discusses how to configure your host linux computer to server TFTP (trivial file Transfer Protocol).
This is useful if you wish to use the netflash program (on the Lbox itself) to load a new lnux or bootloader image to a memory partition.
Once configured the netflash command will be something like this:
netflash -kbr /dev/mtd0 foo.machine colilo.bin
mtd0 is where the bootloader lives
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November 09, 2004
"My laptop doesn't have a serial DB9 so it can't talk to the LBOX serially. I've used my main box for that. However, I just got a USB-to-serial adaptor which allows me to use the laptop serially with the LBOX. I should mention that in the article series because lots of folks have such laptops nowadays.
For my laptop I have a Belkin F5U409 USB-to-serial DB9. Linux has the needed driver (mct_u232). "
(Courtesy R. Sevenich, Eastern Washington University.)
---
The LBOX has a serial port on board that comes out to a 2x5 pin header. An adapter cable can be used to convert this to a "normal" DB9 serial port connector. When the LBOX powers up, you can watch it booting, and eventually you will get a command prompt, and can control the operation this way.
It should be noted however, that it is not ENTIRELY necessary to have a serial connection to the LBOX. If it is configured properly, it will either get an IP address through DHCP, or you can assign a specific one.
For example:
ifconfig eth0 192.168.1.150
- will assign that specific IP address to "eth0" the ethernet port on the Coldfire processor.
If no address is already assigned to eth0, use DHCP:
dhcpcd
- will request dhcp address from a DHCP server attached somewhere on your network.
Either of these commands can be added to the "rc" file in order to have this happen on boot. In this case you just have to wait long enough for the boot sequence to be ready, and then you can telnet into the board. to get a console prompt.
To telnet on to the board:
telnet 192.168.1.150
Finally, in case you are on the LBOX, and want to get to the "outside world" you may need the following line:
Add a default gateway route:
route default gw 192.168.1.1
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November 04, 2004
The LBOX comes pre-configured with BOA webserver .
We do all our cgi-bin in C. Please follow the BOA link for more details.
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October 20, 2004
- What is the processor used in the LBOX?
- Is it a Motorola 68K?
- What speed does the processor run?
- How much memory is there?
To answer your questions:
Motorola Coldfire MCF5272. Coldfire is the "next generation" after the 68K. The instruction set and software architecture is essentially the same, but Motorola removed some op-codes(microcode) in order to optimize the design. Internally it's completely different and on a much more advanced Silicon Fab. Process. It should be noted however that in uClinux this architecture is supported under the "m68k" toolchain, and referred to as such.
We run the board at 48Mhz. The processor technically can run up to 66Mhz, but this would require a crystal change, and software (bootloader) changes. We chose 48Mhz Because it was the best balance between low power, design, and code performance.
There is 4 Meg of flash and 8 Meg of SDRAM.
The Bootloader, compressed Linux plus filesystem image take up about 0.5Meg of flash. At boot time the bootloader runs in Flash to de-compressed and copy the Linux image on the fly from Flash to SDRAM. When done, the bootloard jumps to SDRAM, and execution of the Linux takes place from SDRAM.
The present uCLinux image we use then installs a MTD driver, and mounts 2 meg of the remaining flash as a JFFS2 filesystem. This basically means you have a "mini-harddrive" in flash. the MTD driver is also used by netflash to allow you to reprogram any of the flash partitions over ethernet.
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Q: I'm actually cooking up my own embedded Linux distribution, so I wouldn't be using uClinux. That leads me to the following question: is it possible to overwrite the entire contents of the flash drive?
Yes you can re-flash the whole device. But you should note a couple of things:
- You will probably still want to use uClinux.
- You can still cook your own distro using uClinux. You have total control, and can include whatever you want. uClinux is basically your choice of kernel 2.4.xxx or 2.6.xxx and whatever root filesystem stuff you want to put in. Because small size is so important on an embedded board, you use uClibc and tend to use Busybox to provide various standard functions.
- The processor is a MCF5272 - It does not have an MMU, and therefore requires the use of uClibC. All this means in a practical sense is that you have to call vfork() instead of fork() inside your code.
- There are several flash blocks/partitions currently defined. You could flash the device so that it will no longer boot by itself, or the kernel you flash might not work. Using a BDM module+adapter and GDB will allow you to recover and program a totally blank board.
- Also with the BDM, you can simply load a new image into ***SDRAM*** and start executing. This way you don't clobber the known good boot image.
- We mount part of the unused flash as a JFFS2 filesystem. This makes for a nice place to try code, or update webpages.
- Alternatively you can use the LBOX to MOUNT an NFS partition from your development computer. CrossCompile on it, and it's immediately available to run on the LBOX.
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September 30, 2004
Attached is a little tutorial on ethernet connections, nfs mounting etc...
courtesy Richard Sevenich, Eastern Washington University.
Download pdf file
(Updated with new file Nov9/2004.)
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September 28, 2004
Thank you to Richard Sevenich from Eastern Washington University for this useful HOWTO for the LBOX board.
Configuring minicom to connect to the LBOX.
As root open minicom in setup mode as follows:
# minicom -s
You will get the main configuration menu, looking something
like this:
------[configuration]-------
| Filenames and paths |
| File transfer protocols |
| Serial port setup |
| Modem and dialing |
| Screen and keyboard |
| Save setup as minilbox |
| Save setup as.. |
| Exit |
| Exit from Minicom |
----------------------------
First choose "Serial Port Setup". In the resulting submenu,
modify settings (probably items A, E and G) so that the
submenu matches this one:
------------------------------------------
| A - Serial Device : /dev/ttyS0 |
| B - Lockfile Location : /var/lock |
| C - Callin Program : |
| D - Callout Program : |
| E - Bps/Par/Bits : 19200 8N1 |
| F - Hardware Flow Control : No |
| G - Software Flow Control : Yes |
| |
| Change which setting? |
------------------------------------------
Of course the "/dev/ttyS0" entry should be changed if your serial port is
different e.g. "/dev/ttyS1" etc. Then return to the main menu by responding to
question at the bottom of the submenu with just a
Next, choose "Modem and dialing" from the main menu. In the
resulting submenu, remove the "Init string" and "Reset
string" sequences so the submenu looks like this:
---------------------[Modem and dialing parameter setup]----------------------
| |
| A - Init string ......... |
| B - Reset string ........ |
| C - Dialing prefix #1.... ATDT |
| D - Dialing suffix #1.... ^M |
| E - Dialing prefix #2.... ATDP |
| F - Dialing suffix #2.... ^M |
| G - Dialing prefix #3.... ATX1DT |
| H - Dialing suffix #3.... ;X4D^M |
| I - Connect string ...... CONNECT |
| J - No connect strings .. NO CARRIER BUSY |
| NO DIALTONE VOICE |
| K - Hang-up string ...... ~~+++~~ATH^M |
| L - Dial cancel string .. ^M |
| |
| M - Dial time ........... 45 Q - Auto bps detect ..... No |
| N - Delay before redial . 2 R - Modem has DCD line .. Yes |
| O - Number of tries ..... 10 S - Status line shows ... DTE speed |
| P - DTR drop time (0=no). 1 T - Multi-line untag .... No |
| |
| Change which setting? (Return or Esc to exit) |
------------------------------------------------------------------------------
Then return to the main menu and choose "Save setup as ..". You will then be
prompted for a name. Let's say you choose "minilbox". After making that choice,
you'll be back at the main menu.
Finally, from the main menu, choose "Exit from Minicom".
If you need to redo the configuration, then as root, enter
# minicom -s minilbox
and go through the steps above as appropriate.
Once you're happy with your configuration, you can start minicom as a non root
user via:
$ minicom minilbox
If you get a complaint that /dev/ttyS0 doesn't exist, you may need to change
the permissions on /dev/ttyS0 e.g. as root:
chmod 666 /dev/ttyS0/
If you get a message that the device is locked, remove the lock file from
/var/lock/.
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