PC floppy adaptor for Amiga - Page 14

Supamax · 28 January 2010, 10:58

Quote:

Originally Posted by Stedy

Looking at options for HD floppy support, looks like it will only work with specific drives and possibly involve modifications to the drive itself. Have a few tests to try at the weekend to ascertain what is needed.

If one of these modifications involves slowing down the drive speed, I (and surely Denis too) will be VERY interesting in how you could manage doing it!

The reason? This could open up the possibility to write long tracks, for example.

EDIT: the best would be if the modification was reversible (perhaps adding a switch?), so that we could "activate" it only when needed.

Stedy · 04 February 2010, 22:44

Hi,

I have re-designed the PCB to us a 16V8 GAl/PAL device for the interface logic, this mops up 4 TTL devices.

This design should support DF0: - DF3: and to help supporting external drives, I will bring out the numerous shugart (floppy) bus signals to some test points. Did consider adding a 23 way d-type connector but as I could not find a 23 way, right angle PCB mount connector, I dropped this idea.

As the design now resides in a GAL/PAL device, I have started to add support for a hack to support HD drives, which can be easily disabled.

Due to the number of changes made to my baseline design, I now need to make another test PCB, to prove the design before ordering 100 PCBs. This will delay the next batch of boards.

Ian

rkauer · 05 February 2010, 00:24

Quote:

Originally Posted by Stedy

<SNIP¹>Did consider adding a 23 way d-type connector but as I could not find a 23 way, right angle PCB mount connector, I dropped this idea.
<SNIP²>

Grabbing those from dead A500 motherboards does not feel wrong for me.

cosmicfrog · 05 February 2010, 01:39

great news steady looking forward to the interface, might even buy one this time if you get the HD sorted out

_ThEcRoW · 18 February 2010, 19:40

Will this adaptor work with the dreaded Samsung sfd-31 drive?. It's the worst drive i can think of for amiga stuff.

Stedy · 19 February 2010, 00:52

Hi,

I've hit a small snag, need to buy/make a programmer for the Lattice 16V8 GAL devices I have. PCB has been etched will build this weekend and then see if it works, if not, a cheapo GAL programmer from Ebay.

@ThEcRoW

No idea about the Samsung drive.
I have five different FDDs for testing, from Teac, Mitsumi, Alps, Epson and one I forget, if I can get the adaptor to work with them it will be the perfect start.

DD support is easy, HD is the tricky one.

@rkauer

I won't be taking dead A500s apart for connectors!

Everything I sell is RoHS compliant, items from an A500 might not be.

The weekend is nearly here so some quality time in the workshop is required.

Ian

27 February 2010, 02:52

Just saw the thread about the floppy driver adapter today, looks like a great project, hope you can get the kinks sorted out, would definitely be up for purchasing one from you when finished.

Kitty · 11 March 2010, 02:59

are these complete and for sale now?

prowler · 11 March 2010, 22:07

Quote:

Originally Posted by Kitty

are these complete and for sale now?

No, not yet.

Stedy · 23 March 2010, 23:48

Hi

Quick project update.

Having trouble making the interface logic fit into the original target device. Will try one more approach before I ditch the 16V8 GAL device.

The alternative is to move to a Xilinx XC9536 CPLD in a 0.8mm package. Bought a couple of these parts together with a 3.3V LDO regulator in case I make this move. The downside to this approach is it reduces the option for kits as not everyone will solder such a fine pitched device. Should be able to prototype this pitch board at home which will help with the timescales.

The day job is keeping me busy 6 days a week at the moment so my time is limited again.

When will they be ready?
Hard to say for certain until I have validated the design. I have a 3 week lead time on the PCBs, necessary to keep the costs down. All the other parts I can have in 1-2 days from Rapid/Farnell.

Currently have 5 amiga related designs, including this one, in various states of progress. My target is to have them all completed by June 2010, then see what interest there is before going into production. More details to follow.

The design part is easy, it's the building and testing that take the time!

Thanks for your interest.

Ian

pandy71 · 07 June 2010, 18:41

HD is tricky due lower rotation of the disk (half) AFAIR this method was used only in Amiga and some IBM computers (PS/2 PS/1 series and some notebooks made by IBM) - limitation by FDC (lack of support for 500kbps rate) - maybe with using additional memory (track buffer) this can be solved (like using one of the old DRAM 41256 or similar memory that will be a kind of the FIFO with switchable clock - reading/writing from/to HD FDD 3x - 4x times 500kbps, and half speed to send.receive data from Paula - oversampling to make easier live with RAW MFM data - no need to sync)

orange · 08 June 2010, 14:23

um, what advantage does this offer over just twisting few wires in cable?

i had used a diode to get RDY signal, but apparently there is even simpler solution for that problem.

prowler · 29 July 2010, 02:20

@Stedy,

The problem I had with my adapters was solved by switching the NRDY jumper to the 1-2 position (Use Clip), even though I am using them in my Commodore machine without the clip attached. With the jumper in the 2-3 position (Normal), the PC floppy drives will not read any disks!

Now I have a question: Can 720K PC floppy drives be used with the existing PC floppy adapter for Amiga? I am hoping to use one of threse drive to read HD media which have been Amiga formatted to 880K, but I do have the option of trying them in a PC with Registered Disk2FDI if the drives are not compatible with the adapter.

Thanks.

Stedy · 30 July 2010, 18:42

@Prowler,

Unsure why your adaptor works as it does. Can you change disks ok with the nRDY output removed?

You can format DS/DD disks as 720K PC disks. If you have a DS/HD disk, cover up the HD hole before formatting the disk. The adaptor does work with PC disks.

Ian

prowler · 30 July 2010, 22:50

Quote:

Originally Posted by Stedy

Unsure why your adaptor works as it does. Can you change disks ok with the nRDY output removed?

I'm not sure either. I have two of these adaptors and they're both acting the same way. Yes, I'm using them with a Commodore machine, so I don't have the clip connected whichever way the nRDY jumper is configured.

Quote:

Originally Posted by Stedy

You can format DS/DD disks as 720K PC disks. If you have a DS/HD disk, cover up the HD hole before formatting the disk. The adaptor does work with PC disks.

I was actually asking about the compatibility of the adaptors with 720K PC floppy drives. But I've since discovered that the drive I thought was a Double Density model is, in fact, a High Density drive!

However, I really do have a problem now!

I've blown the 74LS38 chip on one of my adaptors by inadvertently shorting it to the Amiga's RF shield whilst removing it from a floppy drive with the (external) power still applied.

Could you supply me with a replacement chip from your stock of parts, please, to save me a trip to Maplin at Crayford?

I would, of course, expect to reimburse you the cost of it in full.

Thanks.

Eclipse · 03 August 2010, 15:35

If Ian hasn't got one I may have one spare.
EDIT @ Prowler. It's worth having a try with a HD density drive. It should work.

prowler · 03 August 2010, 22:02

Quote:

Originally Posted by Eclipse

If Ian hasn't got one I may have one spare.

Hi eclipse,

I haven't heard from Stedy since I posted that request. If you do have one you could spare for me, I'd be most grateful

, and I'll be careful not to blow another one.

Quote:

Originally Posted by Eclipse

EDIT @ Prowler. It's worth having a try with a HD density drive. It should work.

Yes, everything I've done with this adapter up until now has been with HD drives and, as you say, they work flawlessly.

However, I have some 880K Amiga-formatted HD disks which I cannot read in any Amiga floppy drive or in any HD PC floppy drive using the adapter.

I want to try them in an early 720K PC floppy drive, both with Registered Disk2FDI on a PC and with Stedy's floppy drive adapter on an Amiga.

I have some 720K PC floppy drives which appear not to be compatible with the adapter, and that was the reason for my question.

However, since then, I've discovered that they won't respond correctly as 720K floppy drives when attached to a PC either. They will respond at boot-up as 1.44MB drives, but all subsequent attempts to use the drives result in the "General failure reading drive A:" message.

Now, though, I've got hold of a YE-Data YD702D 6638D dual mode PC floppy drive, which should be able to read these disks when the HD sensing holes are covered with tape. I'm still having problems with some disks, however...

cosmicfrog · 04 August 2010, 10:15

stupid question but did you change the type to 720k in the pc Bios ??

prowler · 04 August 2010, 20:23

Yes, and I all got for my trouble was a "Floppy fail at :40" or similar error message!

orange · 04 August 2010, 20:50

i doubt you can read them in anything now. they say using HD floppies as 880K is not reliable in long term.
maybe you should try that caps dumping tool if they are so important or keep trying with x-copy.

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04 February 2010, 22:44	#262
Stedy Registered User Join Date: Jan 2008 Location: United Kingdom Age: 46 Posts: 733	Hi, I have re-designed the PCB to us a 16V8 GAl/PAL device for the interface logic, this mops up 4 TTL devices. This design should support DF0: - DF3: and to help supporting external drives, I will bring out the numerous shugart (floppy) bus signals to some test points. Did consider adding a 23 way d-type connector but as I could not find a 23 way, right angle PCB mount connector, I dropped this idea. As the design now resides in a GAL/PAL device, I have started to add support for a hack to support HD drives, which can be easily disabled. Due to the number of changes made to my baseline design, I now need to make another test PCB, to prove the design before ordering 100 PCBs. This will delay the next batch of boards. Ian

05 February 2010, 01:39	#264
cosmicfrog The 1 who ribbits Join Date: Apr 2006 Location: leek, Staffs, UK Age: 56 Posts: 3,557	great news steady looking forward to the interface, might even buy one this time if you get the HD sorted out

18 February 2010, 19:40	#265
_ThEcRoW Amiga NetRunner Join Date: Apr 2005 Location: Spain Age: 45 Posts: 942	Will this adaptor work with the dreaded Samsung sfd-31 drive?. It's the worst drive i can think of for amiga stuff.

19 February 2010, 00:52	#266
Stedy Registered User Join Date: Jan 2008 Location: United Kingdom Age: 46 Posts: 733	Hi, I've hit a small snag, need to buy/make a programmer for the Lattice 16V8 GAL devices I have. PCB has been etched will build this weekend and then see if it works, if not, a cheapo GAL programmer from Ebay. @ThEcRoW No idea about the Samsung drive. I have five different FDDs for testing, from Teac, Mitsumi, Alps, Epson and one I forget, if I can get the adaptor to work with them it will be the perfect start. DD support is easy, HD is the tricky one. @rkauer I won't be taking dead A500s apart for connectors! Everything I sell is RoHS compliant, items from an A500 might not be. The weekend is nearly here so some quality time in the workshop is required. Ian

27 February 2010, 02:52	#267
ami_junkie Posts: n/a	Just saw the thread about the floppy driver adapter today, looks like a great project, hope you can get the kinks sorted out, would definitely be up for purchasing one from you when finished.

11 March 2010, 02:59	#268
Kitty Registered User Join Date: Mar 2005 Location: London UK Posts: 1,532	are these complete and for sale now?

23 March 2010, 23:48	#270
Stedy Registered User Join Date: Jan 2008 Location: United Kingdom Age: 46 Posts: 733	Hi Quick project update. Having trouble making the interface logic fit into the original target device. Will try one more approach before I ditch the 16V8 GAL device. The alternative is to move to a Xilinx XC9536 CPLD in a 0.8mm package. Bought a couple of these parts together with a 3.3V LDO regulator in case I make this move. The downside to this approach is it reduces the option for kits as not everyone will solder such a fine pitched device. Should be able to prototype this pitch board at home which will help with the timescales. The day job is keeping me busy 6 days a week at the moment so my time is limited again. When will they be ready? Hard to say for certain until I have validated the design. I have a 3 week lead time on the PCBs, necessary to keep the costs down. All the other parts I can have in 1-2 days from Rapid/Farnell. Currently have 5 amiga related designs, including this one, in various states of progress. My target is to have them all completed by June 2010, then see what interest there is before going into production. More details to follow. The design part is easy, it's the building and testing that take the time! Thanks for your interest. Ian

07 June 2010, 18:41	#271
pandy71 Registered User Join Date: Jun 2010 Location: PL? Posts: 2,871	HD is tricky due lower rotation of the disk (half) AFAIR this method was used only in Amiga and some IBM computers (PS/2 PS/1 series and some notebooks made by IBM) - limitation by FDC (lack of support for 500kbps rate) - maybe with using additional memory (track buffer) this can be solved (like using one of the old DRAM 41256 or similar memory that will be a kind of the FIFO with switchable clock - reading/writing from/to HD FDD 3x - 4x times 500kbps, and half speed to send.receive data from Paula - oversampling to make easier live with RAW MFM data - no need to sync)

08 June 2010, 14:23	#272
orange Registered User Join Date: Apr 2007 Location: Belgrade Posts: 567	um, what advantage does this offer over just twisting few wires in cable? i had used a diode to get RDY signal, but apparently there is even simpler solution for that problem.

29 July 2010, 02:20	#273
prowler Global Moderator Join Date: Aug 2008 Location: Sidcup, England Posts: 10,300	@Stedy, The problem I had with my adapters was solved by switching the NRDY jumper to the 1-2 position (Use Clip), even though I am using them in my Commodore machine without the clip attached. With the jumper in the 2-3 position (Normal), the PC floppy drives will not read any disks! Now I have a question: Can 720K PC floppy drives be used with the existing PC floppy adapter for Amiga? I am hoping to use one of threse drive to read HD media which have been Amiga formatted to 880K, but I do have the option of trying them in a PC with Registered Disk2FDI if the drives are not compatible with the adapter. Thanks.

30 July 2010, 18:42	#274
Stedy Registered User Join Date: Jan 2008 Location: United Kingdom Age: 46 Posts: 733	@Prowler, Unsure why your adaptor works as it does. Can you change disks ok with the nRDY output removed? You can format DS/DD disks as 720K PC disks. If you have a DS/HD disk, cover up the HD hole before formatting the disk. The adaptor does work with PC disks. Ian

03 August 2010, 15:35	#276
Eclipse Turpentine Join Date: Oct 2007 Location: Kent, United Kingdom Posts: 744	If Ian hasn't got one I may have one spare. EDIT @ Prowler. It's worth having a try with a HD density drive. It should work.

04 August 2010, 10:15	#278
cosmicfrog The 1 who ribbits Join Date: Apr 2006 Location: leek, Staffs, UK Age: 56 Posts: 3,557	stupid question but did you change the type to 720k in the pc Bios ??

04 August 2010, 20:23	#279
prowler Global Moderator Join Date: Aug 2008 Location: Sidcup, England Posts: 10,300	Yes, and I all got for my trouble was a "Floppy fail at :40" or similar error message!

04 August 2010, 20:50	#280
orange Registered User Join Date: Apr 2007 Location: Belgrade Posts: 567	i doubt you can read them in anything now. they say using HD floppies as 880K is not reliable in long term. maybe you should try that caps dumping tool if they are so important or keep trying with x-copy.

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