The DDI-2

[plazma]

Dang.... I was going to name my project DDI-2
My version is more like a clone with additional features (ready & side switches, pause, reset, parados+original ROM). It uses the original chips. Logic chips changed to smd.
The 64k additional RAM sounds interesting. Any schematic for it?

[TotO]

I said "if not require extra IC".

It's not possible to indefinitely add features... On my WIP boards, I have to make choices too.
I would like to add, add, add features because each time it's only a simple IC more, but at end the board come no more routable without increasing too much it's size. (that is actually this board problem)

More features is always great, but like usually a choice need to be done to feet on a 10x5cm or 10x10cm maximum PCB size, else the price explode.

[Bryce]

I did some thinking and staring at the schematic last night and decided to change a few things. The board will now have a separate header for Drive A: and B: this makes "ABBA" possible without a switch and also solve the "FD-1 and 3.5in on the same cable" problem.
Still not sure about how I should implement the ready signal switch properly. Same with the side switch - Before someone says "It's easy, you just short pin x to ground", that's unfortunately not a good idea. The cables that offer this forget to mention one important fact: If you close the ready switch and the other drive can supply a ready signal, you are shorting the output of a logic IC to ground. This is a really bad idea. It will work, but it's only a matter of time before the drive with the ready signal fails. The side switch is exactly the same, but this time you are shorting the output of a DDI-1 or 664/6128 logic IC, which means that will eventually fail instead. I'd prefer my device not to endanger any hardware no matter how ham-fisted the user is.

Bryce.

[MaV]

A wonderful idea, and I'll buy at least one for sure, no matter what extra features will be included.

[gerald]

Still not sure about how I should implement the ready signal switch properly. Same with the side switch - Before someone says "It's easy, you just short pin x to ground", that's unfortunately not a good idea. The cables that offer this forget to mention one important fact: If you close the ready switch and the other drive can supply a ready signal, you are shorting the output of a logic IC to ground.

Isn't drive interface using open collector output ? Shorting a pin to ground should not do any damage.
however, I do not like the idea of shorting the ready signal. I prefer finding an alternative way of generating one.

[Devilmarkus]

But there is plenty of software supporting 4 drives

Really?
Where?
Want to do more testings...

[Bryce]

Isn't drive interface using open collector output ? Shorting a pin to ground should not do any damage.
however, I do not like the idea of shorting the ready signal. I prefer finding an alternative way of generating one.

For the side switch: The DDI-1 and 6128 use a NAND gate 7400 or 74LS38 which are open collector, so that shouldn't be an issue. My device uses a 74LS240 which would be an issue.

For the ready signal it's a different story, you can't be sure what the floppy drive is using, it could be either and there are so many different versions of drives. I'm not sure what the HxC uses, there are different versions. The original used a 74LS01 for the ready signal, but I think the latest version just uses a PIC output pin, so it's better to play it safe than have someone screaming "Your DDI-2 broke my HxC / floppy or whatever".

Bryce.

[TFM]

Really?
Where?
Want to do more testings...

See previous posts.[nb]Sorry, can't help more. That's not my PC and I don't have my links here.[/nb]

[TFM]

I did some thinking and staring at the schematic last night and decided to change a few things. The board will now have a separate header for Drive A: and B: this makes "ABBA" possible without a switch and also solve the "FD-1 and 3.5in on the same cable" problem.
Still not sure about how I should implement the ready signal switch properly. Same with the side switch - Before someone says "It's easy, you just short pin x to ground", that's unfortunately not a good idea. The cables that offer this forget to mention one important fact: If you close the ready switch and the other drive can supply a ready signal, you are shorting the output of a logic IC to ground. This is a really bad idea. It will work, but it's only a matter of time before the drive with the ready signal fails. The side switch is exactly the same, but this time you are shorting the output of a DDI-1 or 664/6128 logic IC, which means that will eventually fail instead. I'd prefer my device not to endanger any hardware no matter how ham-fisted the user is.

Bryce.

Agreed! And further supported from the software side: A lot of software depends on a working Ready signal, so a shortcut would be a really bad idea.

[beaker]

Dang.... I was going to name my project DDI-2
My version is more like a clone with additional features (ready & side switches, pause, reset, parados+original ROM). It uses the original chips. Logic chips changed to smd.
The 64k additional RAM sounds interesting. Any schematic for it?

I thought it sounded familiar 
Yeah, I still like the idea of just having an all-in-one solution where the DDI and RAM is included to allow you to run most commercial games straight out of the box as this is the version I'd prefer, but at the same time I can see Bryce's point that having a seperate module would allow it to be used by 6128 and 464 users as this also makes sense. Personal preference at the end of the day...

Then all we need is a Multiface II built in (as they're going for stupid money) so we can save the game state by dumping the memory to a disk image on the HxC, and allow you to poke around the memory and it'll be perfect  Maybe at that point you should call it the DDI-Ultimate in homage to that C64 all in one cartridge (http://www.1541ultimate.net/content/index.php?option=com_content&view=article&id=42&Itemid=20)

No idea about the schematics though, sorry.

[TFM]

I agree with Bryce a Floppy should stay a floppy and shouldn't become an Symbiface or whatever.


Focus should IMHO be kept on Floppy-related features 




Bryce will care about a 4 MB RAM expansion, ups 512 KB RAM expansion in Future anyway. 

[beaker]

Yeah, I am just musing that if there are 2 similar projects, why not have one aimed at people coming back to the CPC 464 (now we're all heading to middle age) or are curious about the machine, who are not necessarily enthusiasts like pretty much everyone here, and just want a single bit of kit they can plug into the back of the machine that will let them load any commercial game from a HxC or FD-1 without having to worry about things like memory.

Then Bryce's one can be the all singing, all dancing one that you can connect anything you want to.

We're quite a small scene and it may open it up to new people if there is a market?

If not, I am talking bollocks and ignore me 

[TFM]

Just get a Symbiface II, then you have all you want. 

[steve]

Is Symbiface still available?, where from?, how much?

[Bryce]

Is Symbiface still available?, where from?, how much?

From someone who's willing to sell you theirs, probably for about €100

Bryce.

[beaker]

From someone who's willing to sell you theirs, probably for about €100

Bryce.

What?!? Mine has devalued by €20 in under a year, it's as bad as a new car I tells ya 

[TotO]

No chance to expect it's value dropping, as 120€ was its price when available. (since 9 years)
But... "about 100€",  not exclude more.

[McKlain]

it seems more cheap to just buy a 6128 when you have a 464...

[Bryce]

It is cheaper, but if like me you grew up using a 464 and still prefer using that machine and you want to use nice stuff like the HxC, then you aren't looking for the cheapest solution.

Bryce.

[McKlain]

I like my 464, but I would prefer something that takes less space with the same features.

[steve]

Someone might consider a wiki article about fitting a 6128 pcb inside a 464 case, or fitting the coloured keytops from a 464 to the keyboard of a 6128.

[Bryce]

Now that's just butchery if you ask me! ( which you didn't )

Bryce.

[beaker]

What about a  KC compact? Does that have a tape port? Looks nice IT - PC - RFT Kleincomputer KC Compact - VEB Mikroelektronik - Orig. Prospekt |

I would like a CPC 464 again just for gaming as it was the one I grew up with as well, and leave all of the specialist stuff with lower ROM and ROM boards on the 6128.

[TFM]

Is Symbiface still available?, where from?, how much?

Some month ago, for some months(!) Prodatron kept the lines open for everyone to ask for a new SF2. Now the new batch was made in Spring and shipped recently.


Contact him for more details.


The price is like always 120 Euros.

[TFM]

From someone who's willing to sell you theirs, probably for about €100

Bryce.

At Ebay never under 200 Euros. Somebody even sold the CPC-IDE (the predescessor of the SF2) for 457 Euros.