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GW-XTIDE-CF1, a CompactFlash Adapter for XT-IDEs

glitch

glitch

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I just finished laying this guy out and sending off to OSH Park for prototypes:



It's a mezzanine board that should bolt to any XT-IDE that uses the Keystone 9202 ISA bracket, including rev 1 - 4, the one Lo-tech board that uses it, derivatives that use the bracket, and of course the knockoffs that have shown up on eBay :p The adapter is designed to mount on small standoffs that screw down in place of the Philips head screws that normally hold the bracket on, making the CF card accessible through the ISA slot. I'll probably provide a drill/cut template for folks who want to modify their own brackets, as well as modified Keystone brackets for those who just want a drop-in replacement.

Paired with a Slot 8 Support module, this should be pretty handy for XTs and 5155 PC Portables where rear CF access is desirable.

The mezzanine cables to the XT-IDE with a regular old IDE cable, so you can also hook on a second device. There's a master/slave jumper on the adapter, but a lot of CF cards don't want to be anything but master. 5V power is taken from IDE pin 20, which of course the XT-IDEs have supported for a while. Boards that don't support it can be modified easily.

The board is laid out for a 3M CompactFlash adapter, available from the usual sources. It's $4-5 each for the 3M part, depending on how many you buy, but it's a high quality CF slot. I'll be providing the boards, parts kits, or fully assembled, so even if you don't want to do surface mount soldering, you can have a CF mezzanine for your XT-IDE.
 
I always put some bypass caps at the cf power lines, though i’m not sure it’s really needed conversely I never had any problems with stability. Perhaps mainly for microdrive use if they are even still a thing.

Also the connected card should ideally be using HCT buffers with this. I totally agree on the 3M headers, Supply seems to come and go a bit but so much better than the crap on the eBay adapters.
 
A few bypass caps would be a good idea, especially since the IDE cable could be quite long. Buffers supplied with all recent (last two years?) XT-IDE rev 4 kits and assembled boards should be HCT. I'm not sure if I should bother adding a 3.3V regulator for 3.3V CF cards -- I checked my stash, none of mine are 3.3V

I hate cheap interconnects! Not to mention, with a CF socket you're far more likely to pull it off the board if it's a cheap one. Mouser is stocking the 3M sockets, though they do seem to run out and have a longish reorder time, now and then.
 
AFAIK the spec requires both 5v and 3v3 support so that should be ok as it is.
 
I'll be wanting at least two kits. How long do you think I'll have to wait 'till they are available for ordering? Will you be offering them through PM here or other web site(s)?

Greg
 
pearce_jj said:
AFAIK the spec requires both 5v and 3v3 support so that should be ok as it is.
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I'd thought I had read that -- I did the converter based off the CF/CF+ spec, figured that wasn't likely to be wrong!

ibmapc said:
I'll be wanting at least two kits. How long do you think I'll have to wait 'till they are available for ordering? Will you be offering them through PM here or other web site(s)?

Greg
Click to expand...

Prototypes will take a week or so. After that, as long as everything works out, it'll be another week or two for the production run of boards, and then they'll be available. I'll put them up on Tindie at least, probably eBay as well, and of course PM/email orders are always taken.
 
What is the pitch of the solder pads for the CF Adapter? I've done some SMD work, but not terribly fine pitch.
 
0.635mm. To solder by hand, a method that works for me is to use a paste flux like fl22, smear along the pcb, then mount the header and solder down the side lugs ensuring it’s fully flat on the board. Then wet all the pins and pads (with solder) being careful not to bend any. Then apply more flux over that and draw it off using braid. Finally inspect with a magnifier bearing in mind the solder can be wicked up the pins away from the pcb and so cause shorts there too.
 
0.025 inch for us non-metric types :p That's half the pitch of SOIC, and a quarter the pitch of regular through-hole DIPs. I tack down one pin, apply Superior #30 liquid flux, and drag solder. I don't typically have to clean up with wick. Superior #30 is a water-thin organic flux, *super* aggressive, it'll take the tarnish off old silver-plated TI IC pins, and it's water wash so there's zero residue left. When I drag solder, I put a bubble of solder on the chisel tip iron I use, and wipe out and away from the device. Probably need to make a video some day. It should be extra easy with the CF adapter since it has locating pins, and my footprint has matching non-plated holes for them.
 
Glitch's CF adapter is designed to fit the XT-IDE r4 - 3 - 2 - 1 controllers so fits in the same slot space as the controller.
 
Indeed, it does not take up another slot -- important on machines that are already packed, or don't have many ISA slots to start with. It's also going to be better quality than anything you get for a few dollars from China. I sometimes buy really cheap Chinese CF adapters for personal projects, I always buy 5-10 to make sure I get enough that actually work. I've had a handful of XT-IDEs come back to the shop where the only problem was defective cheap Chinese CF adapters.
 
glitch said:
0.025 inch for us non-metric types :p That's half the pitch of SOIC, and a quarter the pitch of regular through-hole DIPs. I tack down one pin, apply Superior #30 liquid flux, and drag solder. I don't typically have to clean up with wick. Superior #30 is a water-thin organic flux, *super* aggressive, it'll take the tarnish off old silver-plated TI IC pins, and it's water wash so there's zero residue left. When I drag solder, I put a bubble of solder on the chisel tip iron I use, and wipe out and away from the device. Probably need to make a video some day. It should be extra easy with the CF adapter since it has locating pins, and my footprint has matching non-plated holes for them.
Click to expand...

Ok. I've soldered SMD Parts with .8mm (.0315") spacing. So the CF connector is a little finer pitch. Maybe a little more light and a better magnifier and lay off the coffee for a day and I just might pull it off! Oops. I mean I just might successfully secure it in place! Without shorts!
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Yeah, it probably won't be a big jump, going from 0.315" to 0.025" -- same general technique, just you might need stronger magnification for inspection afterwards. I picked up a 40x lighted loupe for finer SMD work.
 
You can solder that--just be careful to not bend pins while you're soldering. I can do it and my hands are far from steady and my gaze isn't nearly as sharp as it used to be. A binocular loupe, such as an Opti-Visor can help a lot.
 
offensive_Jerk said:
My V1 xt-ide card has the 90 degree header. I assume this won’t work?
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Sure, it'll work -- the rev 4 cards have a 90 degree header too. The idea is to cable the mezzanine adapter to the XT-IDE with a standard IDE cable, which also allows using two drives. It'll probably make a lot more sense once the prototype comes in and I can get some pictures.
 
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