Rick's b.log - 2012/05/17
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Beagle xM - RISC OS

I'm seeing if I can get a version that will use the s-video output. Apparently there's a build that works (sort of) in NTSC mode. Not ideal, but better than nothing.

Getting a bare version of RISC OS running on the Beagleboard xM (not the original Beagle) is simplicity itself. Forget all the crap you read on the Internet about using !SDCreate and making .scr files.

What you need is the microSD card that came with your Beagle xM, running the 4.25 release of the software. Actually, you really only need the U-Boot part, so if you chucked away Angstrom in favour of Ubuntu or Android or such, then it's okay so long as you kept that version of U-Boot (the MLO and u-boot.img files).

Anyway, you probably have both of those. Pretty hard getting the Beagle xM to do anything without!

First up, grab a copy of RISC OS. Get a copy of the latest stable release for the OMAP3 platform from RISC OS Open.
At time of writing, this is v5.18. [direct link to zip file]

Inside the archive you've just downloaded will be a licence PDF, a ReadMe, and a file called "riscos". Extract "riscos" to the microSD card that you'll be using to boot the Beagle xM.

Next, create a text file called "user.txt" and write into it:

defaultdisplay=tv
mpurate=1000
uenvcmd=mmcinit;fatload mmc 0:1 0x81000000 riscos;go 0x81000000

Note: This text file should have Unix/RISC OS line termination (single LF), not Windows line termination (CR/LF). If your text editor cannot do this, or you don't know how to switch it, you can download my version.

Place the microSD card into your Beagle xM and power up. You will see your regular operating system (Angstrom, Ubuntu, etc) load.

Now shut down your regular operating system.
Angstrom's UI shutdown appears to be another of the many broken things - you can force it by going to a terminal (Ctrl-Alt-F1 and Ctrl-Alt-F2 switch between UI and terminal) and entering:

shutdown -h now

Next? Hold down the USER button and reset the board. Keep holding USER until either the screen clears (or does something different to test bars). You'll hear a beep.

If you have a digital monitor connected, you should now see RISC OS. If not, you may need to play with settings.

Can't see or do anything? Hold down USER and reset the board. Immediately (keep holding USER), press SHIFT and numeric-star on the keyboard. This will force RISC OS to boot to the command line. [let go a second or two after the beep]
You will be in the supervisor (*commands). You should be able to determine this as holding Ctrl and tapping G will make a beep.

For now, you're on your own from this point. I don't have a display to look at, so I'm kinda stuck... Let me know how you get on.

Stuff still to do:

• CMOS ram defs file (saves reverting to defaults every boot) [note - if you plan to make use of RISC OS, there's a "widget" available for £5 from ROOL that will preserve your "CMOS RAM" (settings) - take a look
• Some sort of boot filesystem.

Your comments:

Rick, 18th May 2012, 03:07

I should add - if you get RISC OS going and decide that you want it to be your primary operating system, simply swap the "user.txt" and "uEnv.txt" files around.

Rick, 28th November 2012, 19:39

UPDATE: S-video should work out of the box, there's SDFS for accessing the SD card, plus there is an SDCMOS module to store CMOS RAM data on the SD card as a file.  Things move quickly - pop over to ROOL's site to check on the latest version of RISC OS.