3.5" external on a 464 with DDI-1?

[Velociraptor]

Am I right in thinking I cannot use a 3.5" external drive (the one I have is from Siren software I believe) with a DDI-1 on a 464?


It has the edge connector which I think connects to a 664 or 6128, although I can't check due to a house move.


Ideally I'd like them all connected but I'm fairly sure I've read somewhere, and can't find it now, that it's just simply not possible. What I'd like to do is connect it to the 2nd connector on the DDI-1 cable.

[LambdaMikel]

No, you are wrong - as long as you have a drive that emits the ready signal there is no problem at all with a 3.5" drive and the DDI-1.
If you like, I can show instructions on how to do that.

[Velociraptor]

Oh yes please, I'd love a pointer in the right direction!

[LambdaMikel]

Alright, I'll set up my DDI-1 and 3.5" drive tonight and post some instructions. Stay tuned.

[LambdaMikel]

So, this is the setup I am using.

1. modify the DDI-1 interface such that it is powered by the CPC, rather than the DD1. I put in a switch for that.
http://www.cpcwiki.eu/index.php/DDI_Modification

2. modify the DD1 such that the 5V for the 3.5" floppy can be taken from it. See cable. ALSO, remove the 5V molex inside the DD1 that feeds the 5V into the cable!!!


3. modify your 3.5" drive for DRIVE A/0. Modify it for READY.

http://www.pitsch.de/stuff/amiga/floppy.htm
4. Put it on top of the DD1 and use the "A" connector.
5. Use the B connector for the DD1.



Enjoy!

[LambdaMikel]

... the DDI-1 is really quite capable, once you applied the mod such that it gets it power from the CPC.
Here are 2 other nice configurations.  I just got myself a 5.25" floppy for the CPC, mostly as a technology demo for the kids. Before that kind of hardware becomes completely unavailable.

So, Gotek as A and 5.25" as B. Or DD1 as A, and 5.25" as B.
The enclosure is an external SCSI drive bay, which is handy because it has a real On/Off switch and built-in PSU for 5V and 12V Molex. So I can power both the Gotek and the 5.25" with it. Of course, the DD1 has its own PSU still.
And I can of course also use the 3.5" as A, and the Gotek or 5.25 as B. All kinds of combinations possible.

So, it takes some time to apply the mods, but it pays off because it really increases the versatility of the DDI-1 interface.

[Velociraptor]

I'll be giving this a shot once I've moved house. Thanks very much!

[LambdaMikel]

You are welcome. And last but not least, this little adapter cable is helpful:

[LambdaMikel]

I now made a little PCB to get rid of some of these cables.
The idea is the following:
- the PCB has 2 sockets for A / B connectors for both DDI-1 controller outputs. I am using both connectors in order to recover both Drive Sel A and Drive Sel B lines. For a DDI-3 or DDI-4, only one cable is needed to the controller, as both Drive Sel lines are present in the same connector.
- Then there are three IDC output sockets - two of them point inwards towards the SCSI enclosure for the internal drives, so I can put a 5.25" and 3.5" or Gotek in there. The third output socket is on the back, and it is meant for the DD1 or any other drive.
- Most importantly, there is a 12 Position DIP switch on the back that allows me to turn on and off the individual drive select lines, and for each drive, determine if it get connected to Sel A or Sel B. Or not at all.

Don't know if it works yet, will see :-) But hope it will give me a cleaner solution then all the cable jumpering and cable mods  and such.

If it works, I can share the Gerbers. One benefit is of course that you can then just connect controllers and floppies together just with standard 1-to-1 floppy cables, no mods or second connectors on the cable required. (Well, maybe for READY and Side Select still... I should have added another jumper there... hmm... next PCB revision).

[LambdaMikel]

... and one more version. I have ordered this from OshPark, let's see if it works.
Looking forware to no longer having to jumper the drives or mod the cables for A / B etc.

[LambdaMikel]

Works well for me. With this setup, I can switch freely between any A, B combination between 3 drives (Gotek, 3.5", 5.25").
No more cable mods     

I am attaching the Gerbers in case somebody wants to build one.

https://oshpark.com/shared_projects/rtc6nzZu

[remax]

Nice and tidy !

[LambdaMikel]

SCSI enclosure are quite inexpensive these days....

https://www.ebay.com/itm/SCSI-2-Chassis-Frame-Enclosure/223777657149?hash=item341a30113d:g:ENwAAOSwAk5dioi0

Considering that you are also getting the PSU built in.

So, make one for yourself!

It looks a bit odd sitting next to the tiny 6128 though - almost like a ZX81 next to an Elephant 

[gerald]

It looks a bit odd sitting next to the tiny 6128 though - almost like a ZX81 next to an Elephant 

Not a tiny as the Lilliputian monitor connected to it  How do you feed it ? s-video ?

[LambdaMikel]

Good point  It could also take S-Video, but I am just using the same Scart->HDMI converter that I also have for the large screen:

https://www.amazon.com/TNP-Converter-Adapter-Upscaler-Connector/dp/B0177DG71S/ref=sr_1_5?keywords=scart+to+hdmi&qid=1575825273&sr=8-5