PIC / WD1772 floppy project

A lot of RISC OS software is still sold as floppies.

I would have thought that would have been a simple way too filter out the majority that won’t run in a 32 bit environment?

Are new Floppy Drives still being made – some comments made online seem to have found 2nd user drives in new products.

The common USB drives sold for the PC world – seem to be able to only handle 720/1.44 formats.

(Could it be possible for the PCB inside the Drive be changed – is the hardware of the Drive pretty standard?)

Anyone taken one to pieces!

So if the USB > 1772 works well – Window users of RISC OS Emulators may well be interested.

Would using one of the later controllers WD2791 -WD2797 as suggested above be possible.

Circuit diagram available?

The common USB drives sold for the PC world – seem to be able to only handle 720/1.44 formats.

(Could it be possible for the PCB inside the Drive be changed – is the hardware of the Drive pretty standard?)

Yes, the controller only understands the standard FAT formats.

Anyone taken one to pieces!

My drive has a small controller directly connected to the drive. Remember that there is no 12V and the entire thing must run to under 500mA max, so while it might resemble a traditional floppy…

Would using one of the later controllers WD2791 -WD2797 as suggested above be possible.

I assume your PIC fakes being a microprocessor to talk to the 1772? If this is the case, then at a pinch you might even be able to talk to one of those combi-I/O chips like in the A5000/RiscPC. Then you get proper serial/parallel ports and such as “extras”. Could be something to think about for a v2 release? ;-)

My drive has a small controller directly connected to the drive. Remember that there is no 12V and the entire thing must run to under 500mA max, so while it might resemble a traditional floppy…

Most halfway modern 3.5" drives (e.g. the ones used in all Acorns since the A3000) only user 5V anyway. Typical power consumption is usually quoted as 1-2W, so 500mA should be enough.

5.25" drives on the other hand…

A traditional floppy drive has absolutely zero intelligence, or comprehension of formats, sector sizes, etc.

Hmm looking to controllers instead of an ancient controller and making it into an FPGA perhaps use a controller which is in full production :
http://www.microchip.com/wwwproducts/en/SCH3112

Not handy DIL…

A traditional floppy drive has absolutely zero intelligence, or comprehension of formats, sector sizes, etc.

Nope, but they would connect to the computer’s data/address buses via some sort of floppy controller chip. Modern USB floppy drives are a lot more abstract, presenting themselves as a mass storage device, and the controller “understands” certain disc formats. It’s a shame the controller cannot be programmed to be able to read other (non-FAT) formats. Well, maybe it can? Good luck finding information on it…

Anyone taken one to pieces!

Not particularly interesting, but here you go: https://www.heyrick.co.uk/blog/index.php?diary=20170116

Just a bit of an update…
I’ve been working hard on the FS module and made good progress but I have had to put it on the back burner for a while because the company which I part own is on a big project and a lot of my evenings are being spent on that at the moment.

So far I can read/write/verify/format ADFS L/D/E and DOS 720K disks, and because I have implemented disc record support properly (apart from single density and double stepping), it ought to support any (double density) format.

Error reporting seems to work, disc errors, write protect etc are being reported as they should.
Disc changed and empty detection works.
It turns out it is much faster to request sectors individually rather than asking the WD1772 to do a multisector operation.
Speed of large sector discs is impressive especially skewed E format, its very fast indeed.
Small sector discs 256 bytes and lower, performance is terrible, although after optimisation of the PIC code its now fast in my Windows software at least, its quite a bit harder to do in RISC OS though, its to do with how long each usb request takes, if its longer than a sector gap, it has to wait another revolution.

I have used the upcall vector to detect usb file handle closure, and service calls to detect unplugging and connection of USB.
I had to use buffer manager calls and wait-for-rx etc rather than file ops to talk to USB, as doing file ops during a file op crashes everything!

There have been loads and loads of wierd bugs mainly because of tiny little things that I overlooked were not implemented correctly, like if you overwrite the disc record on mount, you will get an ambiguous disc error etc etc etc. Its been a massive learning curve.

Things to do:
Single density support
High density support (overclocked WD1772 02-02 only)
Re-open USB handles if theyre closed (by unplugging it or doing a *shut) (without crashing the machine! callback maybe?)
Implement missing disc ops like restore, step etc…
Implement timeout and escape handling.
Add multi drive support.
Document PIC communication protocol and create schematic / PCB suitable for others to use.

Does anyone have access to the source for ARCDFS by Richard A. Averill or know how to get it touch with him? I would like to make it 32bit compatible and then I could use it with this project, also I’m looking for the latest version of DFSReader but its vanished of Sprow’s website, does anyone know where I can find it? (edited)

also I’m looking for the latest version of DFSReader but its vanished of Sprow’s website, has anyone got a copy?

You could ask Sprow :) After all it’s probably politer to go direct.

I certianly didnt want to be impolite! I just didnt want to be a mither, but I’ve just emailed him, or at least his website address, I cant seem to find a way to PM on this forum.

but I’ve just emailed him, or at least his website address

So expect an answer soon. Sprow is still a very active user.
Anyway, as soon as this hardware will be available for sell/buy, I’ll get one :)

Does anyone have access to the source for ARCDFS by Richard A. Averill

I have an address for a Richard Averill in Carshalton, Surrey but last contact was 1992. Linked In or Social media might find him!

Has there been any updates to this project?

Someone on the Acorn News Group asking about a USB ‘Acorn’ Floppy use from a new machine.

Sorry I’ve not worked on this since Feb, I got bogged down with work and then kinda forgot about it, I do intend to finish it someday!

I still got a big stack of floppy disks ( ADFS ) which i would be happy to get acess to it on the pi. Qestion about: is there a software for RISC OS, to write a Flopy image on an old RISC OS (Ro4.2 , RPC600) to a file, and a software to read such files on a RISC OS 5.2x?

Yes.

Write with:
http://www.cimbrae.co.uk/Computer/software/adfimager.htm

And read with ADFFS.

Hey William,

I did more or less the same thing… 4550 (using my own firmware framework and USB stack, though) and I used an i82072. Later I decided to try with the SMCC 37C78, mostly because
it doesn’t need an external PLL, and it supports everything up to 2.88MB (and tapes.)

Currently awaiting that chip’s arrival…

Meanwhile, I started playing with a software-only solution, since the chip runs fast enough for it. I will later decide which option to ‘keep’ :)

Would be fun to look at your stuff to compare!

Regards,

Fred

Hi Fred, that sounds ace, I’d love to see that working.

I just dont have any time to complete this project, I dont think I’ll ever finish it.
I’ve decided to share my sources:
https://drive.google.com/drive/folders/13BQDPIrzxEyoi1oimVTXWGukVFjRRhPI?usp=sharing
Hope it helps :)

Has anything been heard about this project?

I knew I had seen somewhere someone doing a controller that supports formats other than just the common ones used by PCs. I just could not remember where. Way kool

Except:

I’ve decided to share my sources:

That is, as might be expected, a 404

Isn’t it the same person that does CJE’s USB mouse adaptor?

Isn’t it the same person that does CJE’s USB mouse adaptor?

No that is Simon Inns

I’ve decided to share my sources:

I wonder if someone took a copy of the sources? If I’d seen the posting I think I would have.

It may be worth asking further on stardot, this sort of think is their bread and butter.

Is there a way of sending a msg to William
from within the Site

Hmm how about this – https://cowlark.com/fluxengine/index