Author Topic: Any instructions how to connect an external floppy to a DDI-1 out there?  (Read 4193 times)

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Offline kawe

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Hi everybody,

thanks to ikonsgr I am now another proud user of a working 3.5'' drive connected to my CPC6128  :) .

However, I really intend to connect this (or another drive) to my CPC464+DDI+1 also.
When loooking for CPC464 specific instructions all I have found so far are explanations concerning the "backwards" powersuppy and the "drive A" issue.
But I *do* own two working FD-1 drives and it were absolutely ok for me to connect the 3.5-drive as B-drive only. So I want to go the "easy way".

Then, there shouldn't be any need for DDI-1 modifications. Am I right?
The only task would be to build a proper connection cable between the B-drive connector of the DDI-1 and the 3.5-drive.

But why the hell is there no single pinout or instruction anywhere to do so?
Everyone states either "impossible" or "I've got it" (but doesn't tell how)  :'( .

I think I understand the specs myself good enough. However, there are in fact differences between the CPC464 and CPC6128 pinouts. And some I might overlook.
And I'm also not sure what to do with the Ready- and the Side-select-signal using the DDI-1.

So, it might be a bad idea to check my thoughts against my hardware and blowing everything up.

Has anybody got a link, an instruction or at least a working pinout from his own work so I could check against this?

Regards




 
« Last Edit: 16:37, 28 March 13 by kawe »

Offline Cholo

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Well i cant really help with any cable modding, but i can offer a alternate solution (perhaps).

If you dont mind opening up one of your 3" drives (big DDI or FD1 drive) you could install a 3.5" drive "inside" of one of them. It cant fit inside of cause and it looks kinda messy .. but it works nicely and isnt more techy than you can do it if you have a set of screwdrivers.

Youll need a internal 3" to 3,5" like this one of cause:
Amstrad / Schneider CPC 664 6128 / Spectrum +3 internal ribbon cable adaptor |

Sadly that cable dosnt come with a power cable as well, so youll have to provide the power for the 3,5" yourself (not that hard tho, can be done with a hdd/Sata- or similar powering kit). Or if you are really techy you can make a powering cable yourself as the DDI/FD1 do supply the right output .. but do be extremely carefull as the amstrad DONT follow the normal pc colour cables.

Another semi-solution-ish (and expensive) is that you can use a HxC floppy emulator as a secondary drive straight on the cable. It does require that you have 1 real 3" drive at the end of the DDI-ribbon to supply the power etc. So the HxC can only be used as a secondary B drive on the middel of the ribbon. Still it works without any modding at all.

Slight warning: do remember that the 3" drives do that powering inside thingy so you should probably not start poking around inside one untill a good hour or more after it has been turned off.
Slight warning 2: these old drives can be fairly hard to dissassemble .. like stuck screws or plastic parts that break easy. Just dont forget you really only need one cable: the ribbon one, so you can keep the other cables attached to the 3" drive with a bit of luck and just extend on the ribbon cable to the 3.5" drive.
« Last Edit: 01:43, 12 March 13 by Cholo »

Offline kawe

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Well i cant really help with any cable modding, but i can offer a alternate solution (perhaps).

If you dont mind opening up one of your 3" drives (big DDI or FD1 drive) you could install a 3.5" drive "inside" of one of them.
[...]

Youll need a internal 3" to 3,5" like this one of cause:
Amstrad / Schneider CPC 664 6128 / Spectrum +3 internal ribbon cable adaptor |
[...]

Thanks a lot for answering. I've already seen this solution but haven't noticed the pre-built cable adaptors yet.
This may become and option in the future. Howerever, I don't want to sacrify an FD-1 at the moment ...

Another semi-solution-ish (and expensive) is that you can use a HxC floppy emulator as a secondary drive straight on the cable. It does require that you have 1 real 3" drive at the end of the DDI-ribbon to supply the power etc. So the HxC can only be used as a secondary B drive on the middel of the ribbon. Still it works without any modding at all.
[...]

I would have never thought I can connect an HxC straight!?
I thought its pinoput has been taken from standard 3.5'' drives.
Or is this completely configurable by jumpers?

Offline Cholo

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I would have never thought I can connect an HxC straight!?
I thought its pinoput has been taken from standard 3.5'' drives.
Or is this completely configurable by jumpers?
Well, i donno the exact inner workings of the HxC but the good thing is that it emulates the old style drives who needs that "ready signal" .. aka like the ancient old 5.25" and 3.5" pc drives. The great thing "back then" was that the amstrad actually uses the same pin-to-pin competely .. so you can actually hook up a old 5,25"/3,5" (note: pc only as Amiga Atati ST etc has different pins) to like a 6128 using a original 6128 cable without any modifications at all.
The big issue with Modern pc 3,5" drives is that these dont do the Ready signal anymore. That is actually the only one pin that is off, so all those "mod'ed" cables you see for sale on ebay is usually a bit of "overkill"-modded just for make it easier AND add a bunch features like side/primary switches that you really dont need for it to work.

Anyways, Ive been using the HxC as a second drive with my 464+DDI for quite a while now. So assuming you have the same cable as me (i do think the one i have is the offical one) and it hasnt been modded, you should be able to hook it up straight to the cable.

All i did was use these exact "secondary drive" settings on the HxC:
Guide for HxC SD Version - CPCWiki
(that dusty picture is actually of my current HxC but with my old SD card).

Here is a couple of pics of my current setup:
http://img827.imageshack.us/img827/573/img0033pw.jpg
http://img59.imageshack.us/img59/7791/img0034pc.jpg

Works great most days. Sometimes .. like 1 in 20 times it can fail to work tho. Donno why but the same also happens when i use the DDI+FD1 combo with the 464. Probably because the hardware is all 25 years old. Also all i need to do is power off everything again and turn it back on and it works again.

One small note id like to add is also that the HxC ribbon connector has a "hole" on top .. where as the amstrad 464 ribbon cable has a "tooth" pointing down. Aka you may need to use a tiny bit of GENTLE force to make the 2 connect. Never had troubles with this myself it as the pins still connect and that the "lego bricks" is a bit "misshapen" only help to get a tighten the connection pin grip. Should you accidentally hook em up wrong .. something ive done quite often as i forget its in reverse .. just power it all off again & hook it up right (never damaged my 464 this way).

Also having the HxC as drive B only you will probably need to copy whole floppies from B to A so you can avoid the "only on primary drive" issue that a lot of commercial software has. Not that big a deal tho as you can copy a whole disc in less than a minut with a good disc/track copy program.
« Last Edit: 00:14, 13 March 13 by Cholo »

Offline TFM

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Not that big a deal tho as you can copy a whole disc in less than a minut with a good disc/track copy program.
With a good one? 20 seconds only (40 Tracks, single-sided).
 
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Offline kawe

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[...] ... so you can actually hook up a old 5,25"/3,5" [to a CPC6128] without any modifications at all.
[...] ... Ive been using the HxC as a second drive with my 464+DDI for quite a while now.
[...] ... you should be able to hook it up straight to the cable.
Thanks a lot. Yes, finally, all seem to be just as simple.
But I'm still very confused by CPCWiki for stating nothing or almost contrary statements:

http://www.cpcwiki.eu/index.php/Guide_on_how_to_connect_a_3.5

Quote from: CPCWiki
Q: Can i hook up a 3.5" to a cpc 464 like this?
 A: No. Hooking up a 3.5" isnt possible without some serious soldering [...].
Also having the HxC as drive B only you will probably need to copy whole floppies from B to A so you can avoid the "only on primary drive" issue that a lot of commercial software has.
Again, I'm more confused now as a couple of days before. While I expected I could not use the external floppy as 'A'-drive when connected to the "B"-drive connector of a "CPC464/DDI-1/FD-1" bundle without an ABBA-switch I learned now the quick'n'dirty shortening DRIVE_SELECT solution will work just as fine as for the CPC6128: The external drive will become the A-drive while the former 'A'-drive (FD-1/internal drive) gets inaccessable ...

Offline Bryce

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"Q: Can i hook up a 3.5" to a cpc 464 like this?
 A: No. Hooking up a 3.5" isnt possible without some serious soldering [...]"

I think the "No" is referring to the fact that you would need a hacked DDI-1 to do this. whereas the 6128 has everything already built in.

"Also having the HxC as drive B only you will probably need to copy whole floppies from B to A so you can avoid the "only on primary drive" issue that a lot of commercial software has."

This is just stating that if you HxC is connected as B-Drive (with no quick an dirty solution), that you won't be able to load games from it, because most games will only load from the A-Drive.

Bryce.

Offline kawe

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I think the "No" is referring to the fact that you would need a hacked DDI-1 to do this. whereas the 6128 has everything already built in.
Yes, that is what I believed at first, too. And you are the one who intruduced this modification, aren't you?
However, this is only true if you completely replace the FD-1 with the external drive. Isn't it?
As long as I also connect my FD-1 to the DDI-1 to the outermost connector I will be able to use my external 3.5'-floppy' not only as as 'B'- but also as (quick'n'dirty) 'A'-drive without any mods to the CPC, the DDI-1 or the FD-1. And this is, what I've never expected at first reading the how-tos form here and elsewhere.

Offline Bryce

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Yes, that's true. The modification is for replacing the FD-1 with a 3.5in / HxC. If you still have the FD-1 connected you don't need to change anything, but you have to put the FD-1 on the last connector on the flat cable.

Bryce.

Offline Cholo

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I think the most importent thing is that you must remember that the 464 and 6128 are 2 quite different machines. And because they are so different .. what works with one machine dosnt with the other.

aka:
6128 (and 664) is a DISC machine and supports disc commands in its operating system. It also powers the internal disc and external disc connector. Hooking up a second drive to a 6128 is luckily quite easy as the cable that normally comes with a 3" FD1 drive is a normal pc single drive cable. As the 6128 powers it all it was quite easy back in the days to replace the FD1 with either a 5,25" drive or a 3,5" as most drives back then had proper jumpers on them to set the "RDY" ready signal. Alas modern floppy drives has no manual jumpers anymore (its all hardsoldered) so to use modern drives (or HxC) you need to solder/mod the "RDY" on a pc cable for it to work with the 6128.

464 is a TAPE machine and supports NO disc commands or drives or powering as such. Adding drive support to a 464 requires you to get a special DDI kit that consist of a box with a rom inside that contains the disc commands/support. As this box isnt powered by the 464 it gets mandatory to have at least 1 real amstrad drive (DDI/FD1) at the end of the special 2 drive cable that comes with the DDI kit. Cant just replace the amstrad drive with a 3,5" or 5,25" or HxC as they dont do the powering. Adding a HxC as a second drive is possible.

But I'm still very confused by CPCWiki for stating nothing or almost contrary statements:

http://www.cpcwiki.eu/index.php/Guide_on_how_to_connect_a_3.5
This is a guide for 6128/664 only .. explaining how to modify a normal pc dual drive cable for 3,5" modern drive hookup. One of the quite common questions is indeed:


Quote from: Wiki

Q: Can i hook up a 3.5" to a cpc 464 like this?
 A: No. Hooking up a 3.5" isnt possible without some serious soldering [...].
As explained above the 464 is completely different from a 6128 so you cant just replace the DDI-kit.

Quote from: EvilCholo
Also having the HxC as drive B only you will probably need to copy whole floppies from B to A so you can avoid the "only on primary drive" issue that a lot of commercial software has.

This is indeed as Bryce said "most games will only load from drive A". Its even a trouble today in the year 2013 .. i can still run into windows based games/software that can mess up royally if i install them somewhere else than their "default" location on drive C.
Anyways, amstrad games/software was quite small programs usually written in machine code to load & run directly from drive A. Secondary drives was also quite a expensive thing so few people had it. So there was really no need or reason to spend extra costly time programming the disc software to be more "userfriendly" towards dual drive users. So even tho the operating software actually does support commands like "|B" = i want my B drive to be my current active drive that i want to load/save/run from .. pretty much all commercial software "ignores" it.
Of cause Today the need to launch software from the B drive is as large as ever as most people has a failing internal A drive and a 3,5" external drive B. This is why the cable is usually modded with a A to B / B to A switch/jumper so that the 6128 gets cheated into thinking the 3,5" is the internal "primary" one.


Again, I'm more confused now as a couple of days before. While I expected I could not use the external floppy as 'A'-drive when connected to the "B"-drive connector of a "CPC464/DDI-1/FD-1" bundle without an ABBA-switch I learned now the quick'n'dirty shortening DRIVE_SELECT solution will work just as fine as for the CPC6128: The external drive will become the A-drive while the former 'A'-drive (FD-1/internal drive) gets inaccessable ...
Not entirely sure what you are asking here  :) but lets put the 464 away for a bit.
So your 6128 ABBA switch seem to be working and as explained above you can use it if you are "lazy" and want to quickly run programs from your 3,5" drive. Or if you want to keep things simple: keep everything "off" so you have both A & B drive working and you can then simply copy from B to A or A to B when you need it.

Anyways, (6128 again) the proper way of using the ABBA (primary/secondary) switch/jumper like with this kinda cable:
http://www.cpcwiki.eu/index.php/Guide_on_how_to_connect_a_3.5
is:
1. turn on drives & 6128
2. once the drives/amstrad has powered on
3. flick the ABBA switch/jumper "on"
4. and the external 3,5" drive will be drive A and 3" will be drive B untill poweroff.
5. after use
6. turn off drives & 6128
7. flick the ABBA switch/jumper "off" (this one is really importent or your drives may act oddly afterwards).

Again i donno if your cable (looked like a single drive pc cable from the picture) is the same as the one (dual drive pc cable) in the wiki link. But im guessing its the same.
« Last Edit: 18:31, 18 March 13 by Cholo »

Offline kawe

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Thanks a lot for all your efforts to dissipate my confusion. I got it now :) .
However, once again, my confusion have never originated in the differences of these both CPCs but in their similarities.
In fact you can even run one CPC model by using the OS and BASIC of the other.
And as long as you have a DDI-1 + FD-1 connected to your CPC464 you will hardly notice any differences (if any at all) from the (AMS)DOS point of view.
But there *are* some differences in the hardware design. Most important is the 'reversed ROM psu technique' used for the DDI-1.
This results in an essential deviation from the standard pinout - at least concerning the 'A'-drive (the drive connected to the very end of the DDI-1 connection cable).
I'm very anxious about frying my CPCs after having awaken them from their deep sleep.
And so I got totally puzzled about all the statements delaring "the CPC464 ist totally different so you can't do this here".
In the end it's very easy:
 - Consider the DDI-1 interface to be a part of the CPC464
 - Consider the connected FD-1 to be built-in
Now, the second ('B'-drive) connector is - besides the different plug shape - merely the 2nd disc drive connector of the CPC6128.

That's all I needed to get confirmed. Many thanks -  :)
« Last Edit: 11:00, 19 March 13 by kawe »

Offline Bryce

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Just to clarify why it's different and why the DDI-1 is powered from the FD-1 and not from the CPC:

There's a slight timing issue when the hardware is initialised, which can cause the 464 not to see the DDI-1 if it only powers up at exactly the same time as the CPC. For that reason Amstrad needed to make sure that the DDI-1 hardware was already fully running before the CPC powers up. Powering the DDI-1 from the CPC will work, but it's not a robust design, sometimes (although quite rare) the CPC would not have found ROM7. This isn't a problem on the 6128, because everything is connected to the same reset circuitry.
This is probably also why they didn't supply the DDI-1 with a through-connector, which in my opinion is one of the most annoying things about it.

Bryce.

Offline TFM

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Thanks' god I started with the CPC6128! ;D
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Offline IanS

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Just to clarify why it's different and why the DDI-1 is powered from the FD-1 and not from the CPC:

There's a slight timing issue when the hardware is initialised, which can cause the 464 not to see the DDI-1 if it only powers up at exactly the same time as the CPC. For that reason Amstrad needed to make sure that the DDI-1 hardware was already fully running before the CPC powers up. Powering the DDI-1 from the CPC will work, but it's not a robust design, sometimes (although quite rare) the CPC would not have found ROM7. This isn't a problem on the 6128, because everything is connected to the same reset circuitry.
So what is the issue, I had my DDI-1 powered from the 464 for a while and never noticed an issue. Which bit has the timing issue?

Offline Bryce

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I have my DDI-1 converted too and I've only once seen the problem occur. When you start the CPC ROM7 isn't initialised, but I never looked into it any further to find out exactly why it didn't get initialised.

Bryce.