The DDI-2

[TotO]

[delete me]

[beaker]

So a Doppelgänger eh? I'd watch out for them 

[TFM]

There is à problem. It´s not me who has posted the previous post with my account !

Looks like, because you do know better about that 






But back to topic!


Now if the DDI-2 WOULD have DS0,1,2 and 3, with also the alternate I/O space, then when using two of the controllers this would be possible:

[Bryce]

Hmmm, smoke and water.... 2 things I like to keep away from my CPCs

Bryce.

[TFM]

Smoke is very important, it drives nearly all electrical components. If the smoke get's lost then it doesn't work any longer...



Maybe you like to create a DS0-3 controller with alternate I/O one day. Patience is a virtue.




BTW: What can the new FDC do what the old 765 can't?

[Bryce]

Do you mean the FDC IC (FDC9266) or the entire device? Here's the answer to both.

- The FDC9266 doesn't do anything new, it's 100% µPD765 compatible, but it has the advantage that the Data separator is integrated into the IC, saving quite a bit of space and components.

- The entire device offers 4 OSs in one ROM, selectable with DIP switches. A ready switch and a side switch are also on board, meaning that you don't need fancy cables or jumpers. The headers are also made so that you can directly connect either an FD-1, 3.5in or HxC without needing modified cables. In fact you can use exactly the same cable for all devices. It also offers a thru-connector for further devices, which the DDI-1 didn't.
The DDI-1 is also getting more difficult/expensive to find, so many 464 users still don't have a solution for connecting a HxC.

Bryce.

[TFM]

Thanks for your excellent answer. I meant the FDC. Actually I was curious about the data separator before. In the CPC, Amstrad didn't make a false compromise about that IC either. Actually they used a really good one. 

[beaker]

- The entire device offers 4 OSs in one ROM, selectable with DIP switches. A ready switch and a side switch are also on board, meaning that you don't need fancy cables or jumpers. The headers are also made so that you can directly connect either an FD-1, 3.5in or HxC without needing modified cables. In fact you can use exactly the same cable for all devices. It also offers a thru-connector for further devices, which the DDI-1 didn't.
The DDI-1 is also getting more difficult/expensive to find, so many 464 users still don't have a solution for connecting a HxC.

Bryce.

... and it will come with an LED light to tell you when it's on[nb]it's been a long week  [/nb] 

[TFM]

All my Floppies got such lights...

[beaker]

but one isn't enough! Soon you'll want another to show which drive letter/number the drive is assigned to... then another to show which ROM image has been selected.... then another to illuminate the ports... then another to illuminate the disk drive opening.... then you'll want to illiuminate the keyboard from behind...  then just putting LEDs on machines won't be enough!!! 

Spoiler: ShowHide

[attach=2]

[TFM]

My Amiga Floppy[nb]connected to my 6128 Plus of course[/nb] has numbers indicating the track the head is on even 

[Bryce]

Amstrad used several different data separators. The DDI-1 uses an FDC9229, but the 6128 uses the FDC9216 which lacks a data clock, so an additional IC (the 74HC161) was needed. Then they swapped again to the SED9420 for the plus computers. All most likely chosen for financial reasons.

Bryce.

[00WReX]

Any updates Bryce 

Cheers,
Shane

[Bryce]

I was out of the country for the last week, so not a lot (nothing) got done. I have the prototype half built, but I was waiting for some parts to arrive to finish it and I have a few repairs I need to get done too. As soon as I have the prototype working I'll report back with some pictures.

Bryce.

[00WReX]

[attachimg=1]

[Gryzor]

More than a month later...


I was saving this thread to read when I had some time to really read all the technical posts.


This sounds awesome. Not using a 464, but I'd definitely want one!

[Bryce]

Unfortunately due to a serious lack of time, I haven't had much time to do anything on this, but I might get some time today

Bryce.

[IanS]

In another thread you said that the DDI-1 had a "slight timing issue" and that's why the DDI-1 is powered from the FD-1.
Any instructions how to connect an external floppy to a DDI-1 out there?

Are you powering you DDI-2 from the CPC expansion bus, and if so, have you fixed the "timing issue"? Can you explain what the problem is?

You also seem to have copied the DDI-1 design for the romboard side of your design almost exatly (nothing wrong with that, it's a known good design) but you don't appear to have included the possibility of setting the rom to be rom zero, without that feature, I'm not sure why you bothered with the XOR gates (IC8 on your design), other than them being open-collector so you can link the output together. Doesn't seem like a lot of effort to add "LK-1" to your design.

If you are fixing the design to Rom 7 only, can you simplify the design?

[Bryce]

The design isn't finished, I may add the link for ROM 0 later. At the moment my main concern was the 9266 circuitry and whether it will work at all, so I just blindly copied the ROM section for now. That part could be completely redesigned later. I'm not 100% sure, but the timing issue seems to have something to do with the setup time / reset circuitry of the µPD765. I know that if you power the DDI-1 from the CPC, that it sometimes doesn't work properly which I can only put down to the 765. I thought at first (in the old post), that it wasn't finding ROM 7, but that doesn't seem to be the case. The rest of the circuitry is pretty simple and shouldn't care where it's getting its power from. If you have any other ideas what it could be, then let me know.

Bryce.

[IanS]

You were the only person that claimed there was a timing issue, I've never seen the issue.

My only suggestion with the design would be to try and keep the disc interface isolated from the rom side, so if/when you create a pcb it would be easy to not-populate the rom side to create a FDC only board for use with a seperate romboard (megaflash, rombo, honeysoft etc.)

[Bryce]

I don't know if it's a timing issue, the only thing I'm claiming is that there IS an issue. Power the DDI-1 from the CPC and you'll see it for yourself. Every third / fourth time you boot it will act as if the DDI-1 isn't connected. The CAT command will display "Press Play then any key". Or at least that's what happens on my 464 with DDI-1.

I did consider making the ROM section optional, but it doesn't make the device that much cheaper. It would be easier to include everything and just add a ROM disable jumper.

Bryce.

[arnoldemu]

I don't know if it's a timing issue, the only thing I'm claiming is that there IS an issue. Power the DDI-1 from the CPC and you'll see it for yourself. Every third / fourth time you boot it will act as if the DDI-1 isn't connected. The CAT command will display "Press Play then any key". Or at least that's what happens on my 464 with DDI-1.

I did consider making the ROM section optional, but it doesn't make the device that much cheaper. It would be easier to include everything and just add a ROM disable jumper.

Bryce.

I saw this happening on a friends 464.

[redbox]

I saw this happening on a friends 464.

I saw this on my 464 and just assumed it was a dodgy connection or edge connector needed cleaning.

Nice to know it's not a faulty device.

[Gryzor]

Return them to Amstrad for a replacement?

[TFM]

Yeah. Sure! Wanna use my Delorian?