Hi,

@Supamax

I had a quick look at the drive controller of the 1581 drive, if I read it correctly, it has a parallel data interface. The Amiga uses a serial data interface so I do not see how my adaptor board can help here. Are there schematics for the 1581 drive anywhere?

@Electroblaster,

Only 3 units left in stock, order before I run out. Next batch will be November.

Bye,

Ian

Commodore 1581 Disk Drive User's Guide

Commodore 1581 Disk Drive Schematics :)

Commodore 1581 Disk Drive Service Manual :D

@Prowler

You gave me more work to do by finding the documents!
They were useful thanks.

@Thread

It looks like the 1581 drive and the Amiga drive are compatible, on paper so my adapter should work. I have no way of testing this though.

Bye,

Ian

Hey, I will not say "I told you" :D

@Stedy,

I replaced the internal floppy drive of my Commodore A1200 with my Mitsumi PC floppy drive via one of your adapters this evening with the intention of having a disk imaging session, but the floppy drive would not read any disks inserted in it!

The drive was being polled, disks inserted were being detected and the drive was spinning up. DF0:, PC0: and MAC0 icons appeared on the desktop each time, but the disk was unreadable in each case.

Running TSGui resulted in the error message "Cylinder No 0 - No Sector Header", i.e. no formatting. :shocked

I have changed the floppy drive, the floppy data cable and swapped to another adapter, but still the problem remains. The adapter is jumpererd correctly. The adapter and floppy drive are being powered from an external AT PC PSU. Supply voltage is +5V.

As far as I can see, everything is set up exactly as it was when I tested one of these adapters for you with my Escom A1200.

Do you have any suggestions what might be causing this problem, please? I'm at my wits' end!

@Prowler

Have you got the nRDY jumper set correctly? The escom A1200 uses the jumper wire, the commodore A1200 does not need it.

The symptoms you describe can be caused by lack of nRDY signal.

@Thread

I have an updated PCB ready for release shortly. The new one is still DD only but now supports DF0: to DF3:, has a modified power connector and the FDD connector is now on the correct side of the board.

Updated pricing and availability will follow.

Yes, I had the nRDY source jumper set in the 2-3 'normal' configuration for Commodore A1200, and the Drive Select jumper set in the 1-2 'normal' configuration for DS1.

I was really looking for guidance on what to expect if, for example the 74LS38 chip was blown, etc.

I'll probably be on the lookout for a couple of those when they're available. :)

I would certainly join the queue for a couple of these also.

@Prowler,

Will post some details on fault-finding my adapter PCB shortly.

@Thread

The plan is to build a prototype PCB shortly for testing. Been on holiday for the past 2 weeks, got to ease myself back in ;)

Thanks, mate! :great :bowdown :)

@Prowler

Took some measurements of the logic outputs of my adaptor board today to aid in fault finding. I found that an old fashioned logic probe worked best, if you don't have an oscilloscope.

With no disc inserted you should read the following logic levels,
IC2A pins 1& 2 logic 1 with a pulse every 2 seconds.
IC2A pin 3/IC2D pin 12, logic 0 with a short pulse.
IC2D pin 13, logic 1
IC2D pin 11, logic 1 with a pulse every 2 seconds.

Inserting a disc creates a flurry of activity.
IC2D will have many pulses, logic 0 & 1 and it follows that pins 1&2 and 12&13 follow the same pattern.

A timing diagram is here:

http://www.ianstedman.co.uk/download...k_clicking.png

Hope this helps.

Ian

Thanks, Ian! :great

I'll check both my adapters in the next couple of days. I don't think I've blown them, but I couldn't find anything wrong with the way I had everything connected up either. :(

I'll let you know what happens. As you know, I am interested in trying one connected to the external drive port next.

Hi,

I built the prototype of my new PCB last weekend, it works fine as DF0: but when I use a PC floppy drive cable, with a twist in it, it fails to work.

The twist in the PC floppy drive cable to allow drives A: and B: swaps pins 10 to 16 which on the PC correspond to:

The twist connects pin 10 to 16, 12 to 14, 14 to 12 and 16 to 10 at the second drive. This works fine for the PC as by default the PC floppy uses Select A/Motor Enable A but the non-standard wiring of the Amiga connects the following pins with a twisted cable.
To make this work, I need /SEL1 on pin 10 and /MOTEA on pin 16.

The PC drive uses pins 10 and 12 to select and enable the drive.

My simple fix to this, is to add two 34 way connectors to the PCB, one for Df0: the other for DF1:, allowing for a PC floppy drive cable with a twist on pins 10 to 16. The other option is a number of jumpers. I don't like the idea of jumpers as there are too many things that can go wrong though it is cheaper than another connector and larger PCB.

Thoughts, comments?

Oh the new PCB has the proper power connectors now and for the production PCB, it will have a right angled power connector.

Ian

how many jumpers would it need?
2 would`t be to bad
any more than 4 and brain will start melting

You probably know this already but 1581 and i.e. Amiga 500 use the same Chinon FB354 drive. I actually took one such Chinon from an A500 to my 1581. Works like a charm. On a side note it should be mentioned that the A500 in question was already in a "use for spare parts" condition. :)

@Protek,

I have modified the design, there will be 3 jumpers in total
#1 selects DF0: or DF1: (via twisted cable)
#2 selects nRDY source, internal or jumper wire
#3 selects Df1: (non-twist), DF2: or Df3: via jumper wire.

Have added another logic device to do the fiddling I require, got to hunt through the junk box to find the TTL part I need.

As always, I will test the design out as thoroughly as possible before releasing the PCB. Had hoped to work on it this past weekend but ended up doing my Christmas shopping!

That's all for now,

Ian

Thanks for the update, Ian! :great

Hello,

It's been a while since my last update but there has been some progress.

I know have a prototype board that works as DF1:/DF2: or DF3: but it has got a little complicated. To get DF1-DF3: I need to latch the MTRx signal, unfortunately this is not available from the 34 way IDC connector, only from the 23 way external drive port connector. To latch the signal requires a 74LS74 d-type flip-flop, another device added to the board.

To cater for the twist in the PC floppy drive cable require an additional TTL device, that or I add many jumpers.

In an effort to reduce the number of TTL devices and jumper links, I am now working on a design for a simple CPLD to 'mop up' this logic. This will take a bit longer to develop and test but will make the end user experience easier.

My current prototype now has the proper PC style power connectors and the power connector is now laying flat to the PCB, making it easier to fit into slimline cases, like the A600/A1200.

I have had a few emails asking when new units will be available, I see little point in making a batch of the original design at this time. All efforts, time allowing are going into this improved design. The improved design will be more expensive, too early to advise on final costs.

When there is more news, I will post it here first.

Modelsim awaits me!

Ian

Remind me. Does this adapter enable HD mode? Or is it DD only?

@Alexh

Current design is DD only.

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 the HD support requires drive modifications, I will drop the idea as the inevitable support issues (why does drive X work and not drive Y, will drive Z work?) will be too much hassle.

Ian