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Fit a USB combo-media drive to your RiscPC

By Ian Jeffray. Published: 13th Jun 2004, 23:00:09 | Permalink | Printable

Hardware How-to

As RISC OS users delve further and further into the realms of digital cameras and other uses of compact storage media, Ian Jeffray shows us how he combined a combo-media drive and the STD UniPod. Disclaimer: This article assumes you're competent with electrical based practical work and any modifications carried out on your kit is done entirely at your own risk.

Driving further
I finally got my hands on STD's UniPod at the Wakefield show in May. UniPod provides a wealth of features on a single podule: USB, twin IDE, 10/100baseT ethernet are the primary functions. Interestingly, the USB function is provided on a four-pin header on the board, as well as two standard USB sockets on the rear of the podule.

Unipod USB header

This gave me an idea - attach an internally-mounted smartmedia to the podule, rather than continue with the external reader I had been using, just to be a bit tidier.

I've been using an insanely handy tiny 6-in-1 USB CM/MD/SM/MMC/MS reader by PQI, and had got this working with STD's 'MassFS' generic USB storage filing system with no particular fuss (Pop 0483:1307=LRTC in !MassFS.OtherDevs) so I had some confidence (whether justified or not) that getting another card reader working would be no big deal, so just picked one that looked nice. I chose the FA402M drive from Mitsumi for 15UKP from scan.co.uk. This drive is a combo floppy drive and multiple card reader in a device no bigger than a standard floppy drive - quite neat, and I was even able to pick the colour of the front bezel to match my machine's case.

The drive connects to the RiscPC via three cables; standard floppy power connector, floppy drive cable, and a USB cable for the reader.

The combo drive

The USB connector is keyed to match the header on a PC motherboard, but the key lug can easily be removed by a sharp knife..

USB connector

..and it then connects straight to the USB connector on the UniPod..

USB connector on the internal Unipod header

..being careful to ensure the four pins match the four wires on the plug (there's an unused hole at one end) Power the machine up and, from the command line, *usbdevices shows that it's working correctly:

Device number 2 (36901c0c) on isp0
Device conforms to USB specification version 1.10
Vendor (0x55aa) :
Product (0xb012) : 8-in-2
Device release : 2.00
Serial number : BB8230BB57

MassFS then needs to be told about the device; take the vendor and product codes from the *usbdevices output and pop them in the "OtherDevs" file inside MassFS. You've got to derive or guess the capabilities of the device and what flags must be provided to MassFS to make it work well with that device. A bit of fiddling around and a few reboots and it seems that the FA402M drive works well with the following settings in the "OtherDevs" file: 55aa:b012=LRTCQ All then works nicely and I was able to read the pictures for this article directly from the SmartMedia card in the drive:

Screenshot of the device in action

Next, getting the floppy drive working. That's a bit more fun. RiscPCs use specially modified floppy drives, as the floppy drive connector is not fully PC standard. Fortunately, this is easy to work around. RiscPCs expect the floppy drive to be configured as Drive 'A'. PC floppy drive are, for various good reasons, set as Drive 'B' and these days can't even be changed to be Drive A. More annoyingly than that, the configuration of the RiscPC drive connector activates the "Motor B" and "Select Drive A" lines to run the drive which is just, well, odd. To fix this, we can simply modify the floppy drive cable, rather than messing with the drive.

You can modify the standard RiscPC floppy cable or, as I did, destroy a PC floppy drive cable, giving the option of going back to a standard RiscPC floppy drive later.

Floppy drive cable

First, slice off the twisted part of the cable - this is NOT the twist we want as it's only for changing full drive B's to A's.

Floppy drive cables

Throw away the bit with the twist. Unhook one end of the cable and separate conductors 10 through 12 (3 wires in all). Twist these wires around, and clamp the cable back together. Remember to count from the red edge of the wire as conductor 1.

Modified cable

This end of the cable connects to the motherboard, turning the RiscPC's interface into (almost) a standard "Drive B" PC interface. You can use this cable to connect a standard PC floppy drive, of course, not just the FA402M.

Close up of the modification

Now we can just replace the RiscPC's floppy with the new FA402M drive, and the job's done.

All done, an RPC in a case

After thoughts
Remaining niggles with this project are that MassFS must be reloaded or manually run from !Boot for the drive icons to appear - the USB subsytem currently seems to be unable to cope with permanently
connected MassFS devices.

Please note that I've had no response from STD about this project, so you connect to the internal USB header at your own risk - I've had no official documentation regarding its use. Note also that the MassFS settings were derived by me by pure experimentation, and I give no guarantee that it won't corrupt your data or lock up the machine. (Although it's been fine reading and writing SmartMedia for me).


STD UniPod website

Previous: DIY laptop photo tease
Next: STD suspends A75, A6 range


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Interesting project. It would be nice if STD took interest in investigating this idea to resolve the manual reboot of MassFS problem? I recently obtained a Portable Storage Device - JetFlash USB 2.0. Would MassFS work O.K. with STD's UniPod and my JetFlash if I didn't have a Combo-Media Drive device attached? :rolleyes: Recently, my school ICT teacher suggested to try a PC type USB device, he says they will connect into my Serial Port. Would his idea work on RISC OS, and with what software - thinking about STD using MassFS? :-o Cheers, Steve.

 is a RISC OS UserSawadee on 14/6/04 3:59AM
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It is also possible to add the Mitsumi devices to an Iyonix. Some models of Iyonix now come with the floppy/card readers supplied. As part of the Iyonix downunder project we fitted Mitsumi FA404-A drives (USB2) and have only had to edit a command to check for this on startup as it caused a timing problem. Now all we have to do is double click on a module kept in the Apps folder until Castle release the updated USB drivers. Will Ling helped to locate the problem and suggested the interim solution.

 is a RISC OS Userrmac on 14/6/04 5:40AM
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You can also fit a freecom FC-1 combined CD/RW & card reader into an Iyonix.

I went down this route because the mitsumi floppy / card reader won't be available in black until july according to their website :-(

I am waiting to see if my wife's new Antec case which has built in card reader will work as well when her Iyonix turns up and it gets recased... :-)

 is a RISC OS Userepistaxsis@work on 14/6/04 8:58AM
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We'd been lining these drives (or modified versions) up for a product release, and were trying to keep it quiet ;)

The internal port duplicates the upper external port, which should be blanked off.

MassFS can easily start with the machine by running MassInst again and selectong "start at boot time" as one of its configuration options - it copes with permenantly attached devices fine.

Thanks for an interesting article Ian. I'm off to ensure that the next batch of our thunder is kept completely under lock and key so there's no chance of you stealing that too ;)

 is a RISC OS Userstdevel on 14/6/04 9:09AM
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epistaxsis@work: "when her Iyonix turns up and it gets recased..."

Why not just buy a Panther Iyonix to start with, and thus save the trouble of re-casing it?


 is a RISC OS Userdgs on 14/6/04 9:28AM
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Ooops sorry. However, if you had answered any of my email about the internal port or MassFS settings, you might have been able to avoid me spilling this. Email to you often seems to get blackholed. :-( Although I do understand how busy you are sorting out the new firmware! Maybe you can at least confirm the MassFS config now? ;-) How about explaining the hidden options that some of the devices specify in their config? (S?) I was as much interested in getting the PC floppy drive working (multiple machines now have new floppy drives here) as I was with the card reader - the internal USB header was just a nice bonus :-)

 is a RISC OS Userimj on 14/6/04 9:31AM
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The MassFS options should be documented - although that may be different for release versions (it's mainly up to Stu to decide what documentation is released).

The options have been through various revisions, and it's possible that it's a legacy one which is ignored now (and should be removed). I have a reasonable idea what "S" would mean, but I won't say what it is unless Stu thinks I should :)

 is a RISC OS Usertribbles2 on 14/6/04 10:50AM
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Heh. OK. When are we likely to see all those funky device sprites getting activated?

 is a RISC OS Userimj on 14/6/04 11:22AM
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Wait until you see this case...

 is a RISC OS Userepistaxsis@work on 14/6/04 12:26PM
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epistaxsis: Will it have space for podules...?


 is a RISC OS Userdgs on 14/6/04 12:35PM
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imj: The sprites are available, but not in 'custom designed' drivers (only officially supported devices can use them).

 is a RISC OS Usertribbles2 on 14/6/04 1:16PM
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Aw. Poo.

 is a RISC OS Userimj on 14/6/04 1:20PM
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imj: It wasn't my idea...

 is a RISC OS Usertribbles2 on 14/6/04 1:27PM
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The Iyonix Panther doesn't have provision for podules, does it?

It is interesting that Castle appear to be shying away from the idea of legacy podules in their 'new' models; podule support was never supplied as 'standard' anyway (the requisite backplane costs another 49 quid).

The Aemulor website offers an interesting take on the subject: "The Iyonix's podule bus is really only intended for ease of prototyping new boards and may never fully support all of the old podules."

 is a RISC OS UserStewy on 14/6/04 1:39PM
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Stewy Does depend on what you mean by 'support' :o). I suspect that the OS support for podules is shipped with every Iyonix.

All of the Intelligent Interface podules are supported on the Iyonix as is the Atomwide triple port serial card (via a third party driver).

It makes it cheaper for us punters who are unlikely to ever need to actually plug a podule card into our IyonixPCs to make the podule backplane an extra cost option.

I believe that a standard RiscPC backplane works if you are feeling particularly tight fisted (albeit you can't put the Iyonix case back on with cards installed ;o)

 is a RISC OS Userblahsnr on 14/6/04 1:58PM
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Podule is a very nice low bandwidth bus - hence for developement stuff it may have got included in the Iyonix.

You also get more room for your connectors at the back - which is groovy :-)


might be done this weekend if the Iyonix arrives this week... :-)

 is a RISC OS Userepistaxsis@work on 14/6/04 2:11PM
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Might just give it a go once my UNI podule arrives from STD. If only I could get MassFS to work with MiniDisc so I didn't have an extra 4 icons on the icon bar. Or only have an icon if there was actually a card in the slot! I suppose eventually the 'Format' option in the menu will actually do something?

 is a RISC OS Usermfraser on 16/6/04 9:58AM
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Just fitted a Mitsumi FA404M. Well pleased with myself. Thanks to Ian for the detailed instructions, they were spot on. The drive is USB 2.0, so I could be said to be "Future Proofed" ready for STD to upgrade my Unipod ;-). Different manufacturer and product IDs, but the other flags work OK. Interestingly, although it handles six types of card, it only shows two "drives" on the icon bar. One for each slot presumably, athough I have only CF cards, so could not try out other types.

 is a RISC OS UserProjjer on 3/12/04 8:10PM
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