DDI-1 DIY

Started by SilverGreen93, 13:05, 19 September 17

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Bryce

Yes, I didn't read you ASCII art properly. I though you were suggesting grounding pin 32 without cutting it.

Bryce.

SilverGreen93

Quote from: Bryce on 10:01, 15 November 17
Yes, I didn't read you ASCII art properly. I though you were suggesting grounding pin 32 without cutting it.


Well then, I'll try to respin the board in a couple of days, including the side switch/jumper and the lower profile, and come back.

khaz

Quote from: Bryce on 15:21, 14 November 17
Edit: It's not a simple "jumper to ground". Here's how it has to be connected: http://www.cpcwiki.eu/index.php/Side_Select_Switch

What's wrong with simply grounding the connection? This is how most cables are made, and it works. See for example http://www.cpcwiki.eu/index.php/Guide_on_how_to_connect_a_3.5%22_drive_to_a_CPC6128/664

Bryce

#28
Because you are essentially connecting the output of a 74LS38 in the floppy controller to ground. This output can supply a maximum current of 250µA. So after a while you will have destroyed at least this output channel of the 74LS38 if not the entire IC. Which is why I recommend people to avoid these types of cable (although they provide me with a steady supply of repair work :) ).

Bryce.

SilverGreen93

New design ready! (v2)
Added SIDE selection jumper as discussed above.
Reduced the overall dimensions to (LxH): 97x93mm
Positioned the ROM beneath the expansion connector.




Bryce

Are you sure that there is enough space under the edge connector for that ROM without the PCB hitting the table?

Bryce.

SilverGreen93

Quote from: Bryce on 10:19, 17 November 17
Are you sure that there is enough space under the edge connector for that ROM without the PCB hitting the table?


Yes, I double checked on my Schneider model. Please measure yourself if there is any Amstrad that needs an DDI-1 and is different.
I left exactly 1 inch from the center of the edge connector to the lowest point on the DDI-1 PCB. The table is at about 1.20 inch from the connector center. So it should not touch the table.
Also, I checked if the ROM+Socket would not hit the Amstrad itself, and as far as I can tell, it it just perfectly flush. I will triple check it again before sending to production.


Bryce

Only the Classic 464's really need a DDI, so if it fits on your Schneider it will fit everything it needs to.

Bryce.

SilverGreen93

That's great then!


One question about the Edge connector: I am planning to make them from ISA motherboard connectors. Is there any easy way I can get the "positioning slot" between two contacts to make it align perfectly with the card edge? Or should I just use some end-caps near the last pins to stop it inserting in the wrong position?

Bryce

The PCB mounted edge connectors are readily available. Use real ones instead of faffing about with a hacksaw on ISA connectors.

Bryce.

SilverGreen93

Hmm... I did a search some time ago on ebay, farnell and tme, but haven't found any exact 50 pin ISA-type connectors. If you know some, please share :)

Duke

Quote from: SilverGreen93 on 11:25, 17 November 17
Hmm... I did a search some time ago on ebay, farnell and tme, but haven't found any exact 50 pin ISA-type connectors. If you know some, please share :)
https://www.ebay.com/itm/5pc-Industrial-Card-Edge-Slot-Socket-Connector-25x2P-50P-2-54mm-0-1-3A-240-50/

Bryce



Bryce

Mouser shipping is cheap within Germany, not sure what they charge outside though. I rarely order single parts though, so the shipping then becomes irrelevant.

Bryce.

SilverGreen93

Looks like the shipping for both mouser and digikey is 20EUR.
That's why I order all my parts from tme or farnell, which for the majority of parts have free shipping in Romania.

Duke

Quote from: SilverGreen93 on 12:04, 17 November 17
Looks like the shipping for both mouser and digikey is 20EUR.
That's why I order all my parts from tme or farnell, which for the majority of parts have free shipping in Romania.
If you buy for 50 euro at mouser you get free shipping. Arrow is also pretty good, iirc. free shipping above 50 us once you have bought some items there before (perks customer or something).

Sykobee (Briggsy)


Nice work, getting hold of DDI-1s can be expensive these days.Next - design a custom Gotek board to plug directly into the floppy port on your expansion :-)
Follow the design with the OLED screen :-)

Bryce

My orders are usually around the €200+. I only order once a month at the most.

Bryce.

SilverGreen93

#44
Quote from: Duke on 12:13, 17 November 17
If you buy for 50 euro at mouser you get free shipping. Arrow is also pretty good, iirc. free shipping above 50 us once you have bought some items there before (perks customer or something).
Yeah, I know, but I won't buy that many parts. I will do a BOM at the end and see what is the cost for 1 pc. and then decide if and where from will I order the components.
I already have most of the components available in my parts jelly bin to make 1 fully populated board (including cutting the ISA connector), so the only part that I ordered was the FDC data separator.


Quote from: Sykobee (Briggsy) on 12:19, 17 November 17[/size]Nice work, getting hold of DDI-1s can be expensive these days.Next - design a custom Gotek board to plug directly into the floppy port on your expansion :-)Follow the design with the OLED screen :-)

That's why I'm doing it. I think you can hook up a Gotek to this interface, as it is 100% compatible with the original one. I don't know what custom board are you expecting, maybe some integration with a USB directly connected to the interface, but I see that others have done that already.


The next logical step to follow is to make a FPGA design to replace the D765 and the FDC data separator. If I manage to do that, the next batch/version of DDI-1 will be a lot easier to produce, more reliable and way smaller.


Bryce

I think I have a load of data seperators somewhere if you need more.

Bryce.

Duke

Also forgot Arrow has edge connector too, I bought some of those once, they are fine for CPC too:

https://www.arrow.com/en/products/5530843-5/te-connectivity

It's fairly cheap and you get 20% off.. Perks shipping is free on US 20.

SilverGreen93

Ordered the PCBs on Sunday, 19/11/2017, received them today via DHL. The manufacturer that I chose is ALLPCB.
I am very pleased with the quality of the boards and especially with the fast processing.
Here are some pictures.
I will start the first assembly hopefully this weekend, and then do some testing.

CraigsBar

You gonna be selling these? Having recently got a cpc 464 again and wanting to avoid another zaxon device.....

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SilverGreen93

Quote from: CraigsBar on 02:00, 24 November 17
You gonna be selling these? Having recently got a cpc 464 again and wanting to avoid another zaxon device.....


Just for curiosity, what's wrong with zaxon's devices?



I will be making a full list of Bill-of-Materials after the successful prototype testing and, after such demands, I plan to offer them in 3 variants: board only, board + parts for DIY, or already assembled & tested.
Please let me know which of them are you interested in and I will be calculating the final cost afterwards.


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