Rick's b.log - entry 2012/05/18

Beagle xM - RISC OS working!

First, I got a build of RISC OS with the s-video port supported. It will speak PAL to the s-video port, but with some quirks (setting an unsupported mode will spew rubbish, and colours are incorrect in 32K and 16M modes). But, you know, it is a lot better than a blank screen!

The ROM archive is currently at:

Drop the "riscos" file within on to the boot microSD over top of the one you might have made yesterday. Then boot the Beagle xM (press the button if need be) and after a brief delay the bars will go away and you'll see RISC OS boot. If you're used to a RiscPC, you'll be somewhat astonished by the speed of the Beagle!

While this was going on, I was also making a case for my Beagle xM. It is a little tupperware-like box that is conveniently Beagle-sized. Here I am checking the holes are in the correct places. I'm no craftsman, the holes were designed to work, not look perfect. I got five boxes for three euros, so I can always attempt a tidier version later! Anyway, you can see the gadget I used to make the holes. I think it is for glass engraving or something. It is pretty awkward to handle, but it got the job done.

Once it was all checked, I used three blobs of glue from a hot-melt glue gun (the corners, except the one by the RS232 port) to hold the board in place. It is intended to be solid enough without the hassle of screws and such.

Now, finally, giving it a test-drive. It is really weird seeing half a gigabyte of memory on a RISC OS machine.

Of course, Real Life got in the way. Going shopping, taking the rubbish up the road to the bin...

Once RISC OS was running, it was simple (albeit a little time consuming) to create the default boot harddisc as described here (under "Putting the HardDisc4 image onto a USB drive" subsection "If you don’t have an existing RISC OS device with USB support".

Essentially, a USB device was formatted FAT and the self-extracting archive and a setup script were placed upon in. Under RISC OS, this device was mounted and the setup script extracted the files to RAMdisc. The USB device was then formatted to ADFS format. The files were then copied to the newly formatted device and it was dismounted to ensure changes correctly written out. Job done.

Notes:

• It is imperative to use a device no larger than 2GiB.
  Anything larger, and DOSFS will choke, potentially corrupting data on the drive.
• Even though it is a USB device, RISC OS sees it as a sort of SCSI object. The reasons are long and boring, just know that this is "normal", not some sort of bizarre error.
• The drive will be formatted to a RISC OS specific format. This means it'll really only work in RISC OS from then on. [not a big deal, really] The reason for this is that RISC OS uses "metadata" for file types instead of suffixes. For example, "myfile.txt" under Windows (or Linux) is "myfile" with type &FFF under RISC OS.

Upon reboot, and with the full boot working, the display was washed out. Press F12 and type:

*WimpMode 28

We can do something about this. Download this file (should be a text file called "BeagleMDF") and place it into !Boot.Resources.Configure.Monitors.Beagle (creating the Beagle subfolder).

• You can, if your Beagle isn't yet online, copy the files using a FAT formatted memory device (remember, no larger than 2GiB!). Use "Save target as..." or similar to prevent Windows inserting CRLF line endings; as that'll mess things up on the RISC OS side.

This mode definition provides the following modes:

• A 640×480 mode - generic.
• A 720×576 mode - to make better use of the available display area. UPDATE! An earlier version (uploaded this morning) offered 704×552, so this is an improvement!

Here's an example of 640×480:

And here's 702×552 (this was offered in an older version of the BeagleMDF and is no longer available):

And here's 720×576 (UPDATE! - this replaces the 702×552 mode):

Once I had the machine set up, I used *SaveCMOS to write a copy of the CMOS RAM (RISC OS term for NVRAM) to a FAT formatted USB device (a second USB drive). This was so I could copy it to the boot microSD card.

What I have done now is erase the file "user.txt" from yesterday. The file "uEnv.txt" was then renamed "user.txt". This means booting up with the user button held down will start Angstrom Linux.

I named the CMOS RAM file "rocmos" and placed a copy on the microSD card [you can download a premade copy], and then created a new uEnv.txt file which looks like this:

mpurate=1000
defaultdisplay=tv
optargs="consoleblank=0"
console="tty0 console=ttyS2,115200n8"
uenvcmd=mmcinit;fatload mmc 0:1 0x8100f800 rocmos;fatload mmc 0:1 0x81000000 riscos;go 0x81000000

note - the "uenvcmd" and everything that follows is all one line; it may be wrapped on your display
[download a copy]

So... there you have it. RISC OS on a Beagle xM with s-video output. I'll do some fiddling/hacking another time, but for now, the latest Sankarea has arrived. ☺

Your comments:

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joe, 19th May 2012, 09:42

In US they call it redneck engineering, still it's better  than paying around $30.00 for specially designed box.  I've made mine out of a small junction box, from local  electronics shop at about $6.00, have to modify the top lead to see what is going on inside the box.

Keith Dunlop, 19th May 2012, 20:30

Welcome to the world of RISC OS on modern blisteringly fast hardware!    I don't know if you've tried it yet but get ahold of those famous artworks files (the midget, the acorn etc.) and you will be shocked to see how fast they render.    They are a favourite of mine when I am demonstrating just how fast a RISC OS computer can be these days - at Wakefield this year I was demonstrating a PandaBoard running at 1.5GHz.    Scary x86 alike numbers aren't they (it has 1GB of RAM!!!)?    You'll find disc access is slow as it is over USB so put !Scrap into a RAMdisc - I recommend memphis as it can give upto 256MB space.    Have fun and enjoy :-D

Patric, 20th May 2012, 10:07

Surprising how usable your S-Video modes seem to be! S/h monitors capable of DVI-D can be had cheaply though. Started with 1024x768 on the Beagle myself, cost me ~30 EUR. Later managed to drive a friend's HannsG @ 1600x900, 50Hz. About the best one can get from a regular monitor. Full HD TV sets will happily display 1920x1080 @40Hz but yeah: they're not that cheap unfortunately. Anyways: welcome to the Beagle, Rick, hope you enjoy the ride!

Colin Ferris, 20th May 2012, 13:17

Good work - but is there any advantage in 'formatting' the drive as apposed to 'Initialising' it?

Rick, 20th May 2012, 21:01

Patric - I don't have much choice so I'll need to make S-video work. What helps a lot is to turn the contrast up a notch and switch off v-bob deinterlacing (works okay for TV but makes RISC OS fuzzy). Where did you find the ~€30 monitor, should I be looking at eBay?    Colin - probably not, but I feel happier knowing that something has cast its eye across the disc so if there is any problem, hopefully the formatter would abort before I put data onto the device.

Patric, 20th May 2012, 23:20

Rick, I originally purchased a 15" Eizo Flexscan n order to get the BB-xM up and running. Since it accepts DVI-D as well as VGA it's now used for my A4000 (much better than the analogue only 19" for vintage machines!). IIRC cost me 39 EUR at the time and since I collected it in Person in their shop downtown Berlin no shipping :)  Quick check on ebay.fr shows several 15 & 17" Eizos within this price bracket, interestingly enough all "de Allemagne" but perhaps you could source one locally? The HannsG I mentioned was actually very good too. As long as it comes with DVI-D you'll be fine and since DVI has now been superseded by HDMI of which the Beagle doesn't make full use anyway (no audio) they tend to be cheap old stock/second hand items. Obviously you'll need a HDMI to DVI-D adapter, was ~15 quid at Maplin I think.

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