XT-FDC project level of interest

[modem7]

PS, the only thing left on the "fix list" AFAIK is doing something with the external connector. It hasn't moved any so if someone would please send me some measurements I could make adjustments as needed.

I don't have the external connector (J1) on my card, and so I can't comment.

 

[modem7]

Thoughts? Ideas? Comments? Please let's discuss.

How about we wait until at least there is a Beta version of the BIOS ?

 

[Chuck(G)]

Okay, here's some measurements for the external connector. Imagine that you're looking at the card from the component side, with the ISA edge connector down and the connector on the right side of the car

Depth of ISA card-edge connector: 0.300"
Distace from rightmost edge of ISA card-edge to right edge of PCB: 0.800"
Centerline of external edge connector mounting holes from right edge of PCB: 0.255"
Center of external edge connector lower mounting hole from bottom of PCB 0.123" (note that the body of the DC-37 is flush with the bottom of the PCB).
Centerline of leftmost external connector pads (pins 1-13) from card edge: 0.300"
Centerline of rightmost external connector pads (pins 14-25) from card edge: 0.200"
Distance between external connector mounting holes (top-to-bottom): 2.500"

If you need metric, just multiply everything by 25.4. My calipers all read inches.

 

[NobodyIsHere]

Okay, here's some measurements for the external connector. Imagine that you're looking at the card from the component side, with the ISA edge connector down and the connector on the right side of the car

Depth of ISA card-edge connector: 0.300"
Distace from rightmost edge of ISA card-edge to right edge of PCB: 0.800"
Centerline of external edge connector mounting holes from right edge of PCB: 0.255"
Center of external edge connector lower mounting hole from bottom of PCB 0.123" (note that the body of the DC-37 is flush with the bottom of the PCB).
Centerline of leftmost external connector pads (pins 1-13) from card edge: 0.300"
Centerline of rightmost external connector pads (pins 14-25) from card edge: 0.200"
Distance between external connector mounting holes (top-to-bottom): 2.500"

If you need metric, just multiply everything by 25.4. My calipers all read inches.

Hi Chuck,

I think we have a problem with the external connector. First, were you able to mount an external connector? If so what was the part number? Would this part also work?

http://www.mouser.com/ProductDetail...=sGAEpiMZZMuKcrGJUvEKSapEJD2K/1VF2U4SWmSu9TI=

My plan was to retain the same PCB dimensions as the XT-IDE so builders could reuse the Keystone 9202 ISA bracket. Getting the XT-IDE PCB dimensions right to support a bracket was painful so I'd like not change it. Especially since most builders will only use the internal connectors AFAIK. So the holes P1 and P4 are separate from the D-sub 37P connector and are fixed to support the default bracket (keystone 9202) as is the right most edge of the PCB.

http://www.mouser.com/ProductDetail/Keystone-Electronics/9202/?qs=sGAEpiMZZMsQtlBhqKq43Qxz2Nh624KC

Would this Keystone 9200-5 37 pin D-cutout bracket work? I think it just connects to the D-sub connector only and not to the PCB itself.

http://www.mouser.com/ProductDetail/Keystone-Electronics/9200-5/?qs=mj8EgzjLv%2bCQAPe%2bZvPCYw==

The depth of the ISA card edge is 0.350"
Distance from rightmost edge of ISA card-edge to right-edge of PCB is 0.925"

Is there a way to reposition the existing external D-sub 37P female connector to be compatible with the Keystone 9200-5 bracket? I am looking instructions to move the whole D-sub 37P connector in relative terms like move it up 100 mils and to the right 200 mils.

Thanks and have a nice day!

Andrew Lynch

PS, one thing I don't like about the ISA form factor as there does not seem to be a consistent standard for the PCB edges and hole positions like the IEEE-696 has for S-100. This drove Hargle and I nuts on the XT-IDE trying to fit the bracket since there was no clear point of origin on the PCB or even agreement on the location of the right-most PCB edge! ARGH!

 

[NobodyIsHere]

How about we wait until at least there is a Beta version of the BIOS ?

Hi

That's fine with me. I thought we were using Sergey's BIOS? The PCB still needs to clean up in the trace route optimizer and there is also the adjustments for the external connectors to figure out.

My idea to get some early production PCBs was meant as a discussion starter since I am getting confused as to where we are going with the XT-FDC project.

There is no hurry. Thanks for your patience! Have a nice day!

Andrew Lynch

 

[modem7]

I thought we were using Sergey's BIOS?

Sergy's last word on the BIOS was, "I have plans to implement a built-in configuration utility that will store configuration directly to the BIOS extension EEPROM. Hopefully I'll get to it later this week." That means that the BIOS still requires patching (via DEBUG, etc.) by the user to set the drive types that the user has.

Also, I brought to Sergy's attention the fact that I found that CheckIt's floppy test was reporting errors when I had his BIOS loaded. I don't know if he has had the chance to look into that yet.

I think that if we wait until the built-in configuration utility is ready, then we have a better chance of getting 20 "firm" pre-orders.
But we could choose the option of having early buyers select a BIOS image from a set of preconfigured images.

BIOS extras such as 4-drive support, primary/secondary support, can come later.

 

[Chuck(G)]

Hi Andrew,

I did put an external drive connector on my board, but the placement on the board didn't allow it to be used with a bracket. The connector was pushed so far out that it couldn't sit in an ISA slot normally, so I tested it in an extender card.

Checking my measurements, the Keysttone 9200-5 would work just fine for the measurements that I gave. That seems to give the most leeway on card height, since the connector is more or less flush with the bottom edge of the card.

The connector I'm using is an old Cinch part, but is pretty standard. The connector you linked to has only 9, 15 and 25 pin connectors dimensioned on the mechanical drawing, so it's hard to say for that part. However, this one looks right. It could well be that the part you specified would work, I just don't have any measurements for it.

Let me know if you need some adjustments. The customary mounting is to use the D-sub jackscrews for these, which may create problems for those not wanting to use the external connector. Is there a bracket that works better?

 

[NobodyIsHere]

Hi Andrew,

I did put an external drive connector on my board, but the placement on the board didn't allow it to be used with a bracket. The connector was pushed so far out that it couldn't sit in an ISA slot normally, so I tested it in an extender card.

Hi Chuck,

If the external connector is sticking too far out then I need to move it to left. Is that correct? How far in inches (or mils)?

Would work better if we used the secondary controller dual row header with a ribbon cable to an IDC D-sub 37P connector and it to the Keystone 9200-5 bracket? That might make more sense and it would simplify PCB trace routing significantly.

The above approach worked well on the XT-IDE V2 since most builders are not using the external serial port remote boot mechanism. Those that use the serial port use a ribbon cable to IDC connector and bracket.

Thanks and have a nice day!

Andrew Lynch

 

[Chuck(G)]

Hi Andrew,

Well, that's certainly an option--and it might make most people happy--just use a second ISA slot and a short length of ribbon cable and two IDC connectors to provide something for those with external drive boxes taking DC37 connectors. It'd free up some real estate as well. A lot of PCIe and AGP display cards do the same sort of thing with the VGA connector to allow use in a low-profile chassis, so the idea isn't anything new.

 

[NobodyIsHere]

Hi
Well does anyone object to the idea of dropping the external connector and just using the internal connector via ribbon cable and IDC D-sub 37p for external floppy support?

Please speak up! Thanks and have a nice day!

Andrew Lynch

 

[Maverick1978]

Hi
Well does anyone object to the idea of dropping the external connector and just using the internal connector via ribbon cable and IDC D-sub 37p for external floppy support?

Please speak up! Thanks and have a nice day!

Andrew Lynch

Not I! - If I purchase this device (and I plan to), it will go into a full tower with more slots available than most motherboards can handle anyway. For me, this is a non-issue.

 

[ibmapc]

Hi
Well does anyone object to the idea of dropping the external connector and just using the internal connector via ribbon cable and IDC D-sub 37p for external floppy support?

Please speak up! Thanks and have a nice day!

Andrew Lynch

I would prefer to keep the external connector. I'd use this card in my 5155 to connect the stock internal 360K drives and an external 3.5" drive. Since I don't have extra ISA slots available, I would not have another spot to mount a connector. So, that's my two cents worth.

Greg

 

[dpatten]

Hi
Well does anyone object to the idea of dropping the external connector and just using the internal connector via ribbon cable and IDC D-sub 37p for external floppy support?

Please speak up! Thanks and have a nice day!

Andrew Lynch

I would be mounting all drives internally, so I would have no use for an external connector.

 

[SpidersWeb]

No external connector needed for me.
I don't even need a BIOS at this point, just want 3 drives on the same channel.

 

[NobodyIsHere]

Hi Andrew,

I did put an external drive connector on my board, but the placement on the board didn't allow it to be used with a bracket. The connector was pushed so far out that it couldn't sit in an ISA slot normally, so I tested it in an extender card.

Hi
The XT-FDC board continues to improve in the PCB trace route optimizer. It is at 182 vias and less than 600" overall trace length. That's pretty good for its parts density.

Chuck,
can you measure how far to the left the external connector would have to move to be useable with a bracket? Is it like 0.1"-0.2" or so or does it have to move more than 0.2"?

Thanks and have a happy holidays!

Andrew Lynch

 

[NobodyIsHere]

Hi!
A couple of questions on the XT-FDC project

1. Does anyone have a detailed parts list/BOM preferrably with vendor part numbers they would please post to the wiki? That would be helpful.

2. in light of Sergey's ISA Floppy and serial controller board is the XT-FDC project overcome by events? Do we really need two ISA floppy controllers?

Thanks and have a nice day!

Andrew Lynch

 

[pearce_jj]

Hi!
2. in light of Sergey's ISA Floppy and serial controller board is the XT-FDC project overcome by events? Do we really need two ISA floppy controllers?

There's also the option to use a 16-bit multi-IO card, and get IDE for CompactFlash too. But that shouldn't stop you making this board, IMO

 

[NobodyIsHere]

There's also the option to use a 16-bit multi-IO card, and get IDE for CompactFlash too. But that shouldn't stop you making this board, IMO

Hi

Well that's the point. If there are one or more alternatives already why are we making yet another? Too many similar projects just dilutes the already thin demand for the boards making all of the projects less economically viable.

I think we need to be "clear eyed" and discuss the future of the XT-FDC project.

Thanks and have a nice day!

Andrew Lynch

 

[ChrisCwmbran]

My understanding from reading this thread - although I'm probably wrong - is that Sergey's board only supported two floppy drives?

I know I'm just one minor voice, but the important thing for me is support for four floppy drives.

 

[dpatten]

My understanding from reading this thread - although I'm probably wrong - is that Sergey's board only supported two floppy drives?

I know I'm just one minor voice, but the important thing for me is support for four floppy drives.

This is my understanding as well. I've already got a High density controller than can run two drives. I'd like to have four.